Earlier this month, NASA’s TESS space telescope successfully captured the faint glow and tail of an interstellar comet, further enriching its archive with observations that may provide critical insights into this unique celestial visitor from beyond our solar system.
This 3I/ATLAS image was captured by NASA’s TESS satellite on January 15, 2026. Image credit: NASA/Daniel Muthukrishna, MIT.
The interstellar comet 3I/ATLAS was discovered on July 1, 2025, by the NASA-funded ATLAS survey telescope in Rio Hurtado, Chile.
Known as C/2025 N1 (ATLAS) and A11pl3Z, this comet originated from the Sagittarius constellation.
3I/ATLAS holds the record for the most dynamically extreme orbit of any object tracked in our solar system.
It reached its closest approach to the Sun, or perihelion, on October 30, 2025.
The comet passed within 1.4 astronomical units (approximately 210 million km) of our Sun, just crossing Mars’ orbit.
After its brief obscuration behind the Sun, it reemerged near the triple star system Zania, located in the Virgo constellation.
According to MIT astronomer Daniel Muthukrishna and his team, “The TESS spacecraft systematically scans vast areas of the sky for about a month, looking for variations in light from distant stars to identify orbiting exoplanets and new worlds beyond our solar system.”
“Additionally, this technology enables TESS to detect and monitor remote comets and asteroids,” they added.
Notably, 3I/ATLAS had been observed prior to its official discovery in May 2025. For more details, you can read the findings.
From January 15 to 22, 2026, TESS re-observed the interstellar comet during a dedicated observation period.
The comet’s brightness measured approximately 11.5 times the apparent magnitude, making it about 100 times dimmer than what the human eye can perceive.
By revisiting the TESS data, astronomers successfully identified this faint comet by stacking multiple observations to track its motion, showcasing the extraordinary capabilities of the TESS mission.
NASA’s SPHEREx mission reveals that interstellar object 3I/ATLAS dramatically transformed into an active comet following its close approach to the Sun.
SPHEREx imaging of 3I/ATLAS taken from December 8th to 15th, 2025. Image credit: NASA / arXiv: 2601.06759.
SPHEREx monitored 3I/ATLAS from December 8 to 15, 2025, shortly after its perihelion, the closest approach to the Sun.
“In December 2025, SPHEREx reobserved 3I/ATLAS post-perihelion and found it to be far more active than previously observed. August 2025 SPHEREx pre-perihelion observations show significant evidence that it has completely sublimated its ice, transforming into a comet,” explained astronomer Carrie Risse from Johns Hopkins University Applied Physics Laboratory.
New SPHEREx data indicates a gas- and dust-rich coma, revealing emissions of cyanide (CN), water (H2O), organic compounds (CH), carbon dioxide (CO2), and carbon monoxide (CO).
“The emergence of cyanide and organic matter indicates their presence in the aqueous phase,” said Avi Loeb, a Harvard University professor not involved in this study.
Researchers noted a sharp increase in water activity, accompanied by a significant surge in carbon monoxide emissions.
“The H2O gas signature, previously nearly undetectable in August, is now 20 times stronger, indicating complete sublimation of water,” added the researchers.
“CO emission rates have increased by 20 times, as the CO/CO2 ratio has risen 15-fold as well.”
SPHEREx images further demonstrate that the object’s gaseous envelope has expanded significantly.
“The gas comas observed by SPHEREx are distinctly resolved, extending from 1 foot to 3 feet in radius; all but the CN and CH organic comas appear round relative to the Sun and orbital velocity,” scientists noted.
“In contrast, the dust and organic matter images in the SPHEREx continuum exhibit a pear-shaped morphology, with the ‘pear stalk’ directed toward the Sun.”
“These varying shapes suggest that CN and CH are sourced from dust, while H2O, CO2, and CO gases are distributed symmetrically around the atomic nucleus.”
“No visible jets or anti-solar tail structures were detected.”
SPHEREx’s observations indicate fundamental changes in the physical state of 3I/ATLAS.
“December 2025’s observations align with a comet that is fully active and sublimating water ice,” the authors concluded.
The composition now resembles that of typical Solar System comets, with ice content comparable to most comets.
Researchers attribute these changes to the object’s trajectory through the inner solar system.
“By December, 3I/ATLAS had spent 3.5 months within the solar system’s ice line, causing all comet components and volatile CO2 ice to become active,” they stated.
“Consequently, the bulk material of the cometary matrix evaporated, releasing its contents.”
“Further observations are anticipated before 3I/ATLAS passes through SPHEREx’s investigation pattern again in April 2026,” they concluded.
For more information, refer to their paper, submitted for publication in AAS Research Notes.
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CM Lisse et al. 2026. SPHEREx reobservations of interstellar object 3I/ATLAS in December 2025: increased post-perihelion activity, detection of coma dust, and new gaseous emissions. RNAAS submitted for publication. arXiv: 2601.06759
A global team of astronomers from Chile, Europe, the USA, Canada, and New Zealand has achieved an unprecedented level of detail in spectroscopic observations of an interstellar comet as it moves through our solar system. Utilizing spectroscopic data from two instruments on the ESO’s Very Large Telescope (VLT), researchers detected emissions of nickel atoms and cyan gas from the interstellar comet 3I/ATLAS, marking it as the third confirmed interstellar object recorded.
This image of interstellar comet 3I/ATLAS was taken with Hubble’s Wide Field Camera 3 (WFC3) on December 27, 2025. Image credit: NASA/ESA/CSA/Hubble.
The interstellar traveler, 3I/ATLAS, was first discovered on July 1, 2025, using the NASA-funded ATLAS (Asteroid Terrestrial Impact Last Alert System) telescope.
Also referred to as C/2025 N1 (ATLAS) and A11pl3Z, this celestial object approached from the constellation Sagittarius.
At its discovery, the comet was located 4.51 astronomical units (AU) from the Sun, with an eccentricity of 6.13.
“Understanding the volatile components of interstellar objects that pass through our solar system grants us unique insights into the chemical and physical processes occurring in distant stellar systems,” noted Dr. Rohan Rahatgaonkar of the Catholic University of Chile.
“Interstellar objects maintain remnants of the chemical and physical processes active in their protoplanetary disks during formation and may be altered by interstellar medium exposure.”
“When subjected to solar radiation, these cometary interstellar objects emit solids and gases due to their activity.”
During July and August, astronomers carried out high-resolution spectroscopic analyses as 3I/ATLAS approached between 4.4 to 2.85 AU from the Sun.
To acquire the comet’s spectrum, they employed the VLT’s X-Shooter and the Ultraviolet and Visible Echelle Spectrometer (UVES).
Observations revealed that the comet’s coma, the cloud of dust and gas enveloping its nucleus, is primarily made up of dust, with a consistent reddish optical continuum indicating organic-rich materials.
This reddish coloration resembles that of comets within our solar system and primitive Kuiper belt objects, suggesting shared physical processes across the planetary system.
3I/ATLAS spectrum showing Ni I emission over observations from VLT/X-Shooter and VLT/UVES. Image credit: Rahatgaonkar et al., doi: 10.3847/2041-8213/ae1cbc.
As 3I/ATLAS continued its journey towards the Sun, researchers identified emissions of various cyanide (CN) compounds and neutral nickel (Ni).
Interestingly, iron (Fe) was not detected, implying that nickel is efficiently released by comatose dust particles under solar radiation influence.
The rate of production for these emissions increases significantly as the comet nears the Sun, establishing a strong power-law relationship with its geocentric distance.
These observations indicate that the release of these atoms may stem from low-energy mechanisms, like photon-stimulated desorption or the breakdown of complex organics, rather than the direct sublimation of ice. This distinguishes this interstellar comet from many others within the solar system.
This spectral data not only acts as a snapshot of a transient visitor, but interstellar comets like 3I/ATLAS offer pristine samples from materials formed around other stars. Their limited processing from solar proximity preserves valuable clues about distant protoplanetary disks—the swirling clouds of gas and dust which eventually form planets.
Past interstellar discoveries, such as ‘Oumuamua in 2017 and 2I/Borisov in 2019, have exhibited surprising contrasts. ‘Oumuamua appeared inert, while 2I/Borisov showcased an abundance of carbon monoxide and complex ice.
The new insights from 3I/ATLAS contribute another intriguing layer to this expanding cosmic narrative. Its dusty constitution reveals molecular traits that challenge our understanding of typical comet behavior and introduce novel physics.
3I/ATLAS spectrum from the monitoring campaign spanning July 4 to August 21, 2025. Image credit: Rahatgaonkar et al., doi: 10.3847/2041-8213/ae1cbc.
“If 3I/ATLAS maintains the absence of iron while exhibiting nickel emissions during perihelion, it will set a precedent for observing interstellar comet metal emissions decoupled from traditional refractory trends,” the researchers stated.
“This observation suggests a distinct low-temperature organometallic pathway for nickel in exocomets and may provide fresh perspectives on how disk chemistry, metallicity, and irradiation history affect planetesimal microphysics.”
The parent star of 3I/ATLAS is presumed to be less metallic than other interstellar progenitor stars, yet more metallic than the Sun, indicating no inherent conflict between its estimated age and the presence of iron-peak elements like nickel.
“Regardless of which interpretation is accurate, 3I/ATLAS promises a critical experiment linking metal emissions with volatile activation and particle physics in interstellar bodies.”
“The findings discussed will elevate nickel from being a mere curiosity into a crucial marker for determining both parent chemistry and galactic origins, and set new standards for rapid-response spectroscopy of interstellar objects at the Rubin Observatory and ESO’s Very Large Telescope.”
For further details, see the published findings on December 10, 2025, in the Astrophysics Journal Letter.
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Rohan Rahat Gaonkar et al. 2025. Observations of interstellar comet 3I/ATLAS using a very large telescope: From quiescence to luminescence—Dramatic increases in Ni i emissions and initial CN outgassing at extensive heliocentric distances. APJL 995, L34; doi: 10.3847/2041-8213/ae1cbc
Scientists utilized the WISPR (Wide Field Imager for Solar Exploration) instrument on NASA’s Parker Solar Probe to capture stunning images of the interstellar comet 3I/ATLAS between October 18 and November 5, 2025.
WISPR captures the interstellar comet 3I/ATLAS. Image credit: NRL / NASA / JHUAPL / Guillermo Stenborg, JHUAPL.
Discovered on July 1, 2025, by the NASA-funded ATLAS survey telescope in Rio Hurtado, Chile, 3I/ATLAS, also known as C/2025 N1 (ATLAS) and A11pl3Z, originated from the constellation Sagittarius.
This remarkable interstellar comet approached Mars on October 3 at a distance of just 0.194 AU and reached its perihelion, the closest point to the Sun, on October 30.
On December 19, 3I/ATLAS made its nearest pass to Earth, coming within 270 million kilometers (168 million miles) of our planet.
The spectacular images of 3I/ATLAS were obtained by the WISPR instrument aboard NASA’s Parker Solar Probe during a critical observation window from October 18 to November 5.
“The Parker Solar Probe captured around 10 images of the comet daily,” stated WISPR team members.
“During this observation period, the spacecraft accelerated away from the Sun following its 25th solar flyby on September 15.”
“These initial images are currently undergoing calibration and processing, revealing the comet’s movement behind the Sun from Parker’s vantage point.”
“At that time, the comet was located about 209 million kilometers (130 million miles) from the Sun, just beyond Mars’ orbit.”
“These images offer a rare opportunity to study the comet when it was too close to the Sun for ground-based observations.”
The WISPR team is diligently working to finalize the data by eliminating stray light and adjusting for varying exposure times between images, enhancing the comet’s visibility.
“The final images will significantly advance our understanding of this intriguing interstellar visitor,” researchers concluded.
Astronomers utilizing ESA’s XMM-Newton Observatory have captured X-ray images of 3I/ATLAS, the third confirmed interstellar object to traverse our solar system, following 1I/Oumuamua and 2I/Borisov.
This XMM-Newton image displays an X-ray visualization of the interstellar comet 3I/ATLAS. The center features a bright red dot against a dark backdrop, resembling a burning lighthouse. Surrounding this core is a soft gradient of purple and blue, forming a slightly rotated rectangular frame divided by a thin horizontal line, indicating the detector gap. Red represents low-energy X-rays, while blue signifies regions with minimal X-rays. Image credit: ESA / XMM-Newton / C. Lisse / S. Cabot / XMM ISO Team.
On December 3, 2025, XMM-Newton tracked the interstellar comet 3I/ATLAS for approximately 20 hours.
During this observation, the interstellar object was about 282-285 million kilometers away from the spacecraft.
XMM-Newton utilized the European Photon Imaging Camera (EPIC)-PN, its most sensitive X-ray camera, to observe the comet.
“This XMM-Newton image highlights the comet radiating in low-energy X-rays. The blue regions indicate voids with nearly no X-rays, while the red areas showcase the comet’s X-ray emissions,” stated members of the XMM-Newton team.
Astronomers anticipated this glow, as gas molecules emitted from comets generate X-rays upon colliding with the solar wind.
“These X-rays can originate from the interaction of the solar wind with gases such as water vapor, carbon dioxide, and carbon monoxide, and have previously been detected by telescopes like NASA/ESA/CSA’s James Webb Space Telescope and NASA’s SPHEREx,” added the researchers.
“However, these telescopes possess distinct sensitivities to gases like hydrogen and nitrogen.”
“They are almost undetectable by optical and ultraviolet instruments, such as the NASA/ESA Hubble Space Telescope and ESA’s JUICE camera.”
“This makes X-ray observation an exceptional resource,” they emphasized.
“Researchers will be able to identify and examine gases that are difficult to detect with alternative instruments.”
“Multiple scientific groups suggest that the first observed interstellar object, 1I/’Oumuamua, may have been composed of unusual ices like nitrogen and hydrogen.”
“Although 1I/Oumuamua is currently too distant to study, 3I/ATLAS provides fresh opportunities to investigate interstellar bodies. X-ray observations will supplement other data and assist scientists in understanding the composition of these objects.”
Comet Lemon photographed from northern Italy on October 26, 2025
Marcel Clemens/Alamy
Although no one has officially stated it, 2025 has certainly been an exceptional year for comets. There’s Comet Lemon, discovered in January and making headlines for nine months. Each time I encountered that striking long tail formed by the comet’s solar heat, I was captivated.
In September, C/2025 R2 (SWAN) was discovered, radiantly bright even when near the moon on Halloween, making it easily visible. Then came Comet 3I/Atlas, which gained notoriety after a Harvard astronomer—primarily a cosmologist—identified it as an alien probe.
As a cosmologist who recognizes my limited expertise in comet studies, I fully trust the specialists asserting that Comet 3I/Atlas is not some extraterrestrial object. This isn’t a regret; this comet is still scientifically intriguing. Unlike lemons and SWANs, it hails from beyond our solar system, categorizing Comet 3I/Atlas as an interstellar comet.
Its entry into our solar system offers a thrilling opportunity. While pinpointing its exact trajectory may be unattainable, its composition can reveal a wealth of information about its parent star. Essentially, we can learn about the makeup of an enigmatic star even when its identity remains unknown.
Our expedition with this year’s comet reflects a long historical pattern of human fascination with enigmatic celestial phenomena. Most notably, Halley’s Comet’s passage in 1066 was illustrated in the Bayeux Tapestry, symbolizing the onset of the Norman invasion of England. Nowadays, we understand that humanity is not the universe’s focal point, and the universe lacks a center—but it’s easy to entertain the notion that the comet of 2025 could be conveying a message.
Reflecting on this year, filled with distressing and unfortunate occurrences, it’s tempting to ponder whether these comets hint at an impending apocalypse. The state of science in the United States faces turmoil, as the current administration cuts funding and initiatives (see page 20). Moreover, anti-immigrant sentiments have gained a mainstream foothold in both the United States and the United Kingdom.
As a Black and Jewish queer scientist, and an immigrant’s child, maintaining an open heart daily is a struggle. I recognize that there are those who wish to silence me. Contrary to my previous scientific education, I could interpret the comet as a sign to surrender. Yet, alternative paths exist. As a scientist, I perceive comets as sources of hope. They are breathtaking visual havens. The quest to observe them has fostered community. My astrophotography group eagerly anticipates sharing our experiences. While it’s frustrating to encounter rampant misinformation in various media concerning questions like “Are they aliens?”, I feel grateful that attention is being drawn to these phenomena.
For 2026, my aspirations are immense. Scientifically, I yearn for groundbreaking observations of dark matter. Socially, I aim to ensure that all children have access to essential resources—food, shelter, education, and healthcare—in environments that affirm their identities. While these are monumental dreams, they likely won’t manifest by year’s end. Nevertheless, comets remind us of the vast universe, brimming with marvelous surprises. Just as we strive to discover comets, we must also endeavor to create the better world we desire.
The Hubble team has unveiled breathtaking new images of interstellar comet 3I/ATLAS captured by the NASA/ESA Hubble Space Telescope. This marks only the third instance of such a comet being observed.
This image of interstellar comet 3I/ATLAS was captured by Hubble on November 30, 2025. At that time, the comet was around 286 million kilometers (178 million miles) from Earth. Image credits: NASA / ESA / STScI / D. Jewitt, UCLA / M.-T. Hui, Shanghai Observatory / J. DePasquale, STScI.
Discovered on July 1, 2025, by the NASA-funded ATLAS (Asteroid Terrestrial Impact Last Alert System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is a remarkable interstellar comet.
At the time of its discovery, the comet had a heliocentric distance of 4.51 astronomical units (AU) and an eccentricity of 6.13.
This object, also referred to as C/2025 N1 (ATLAS) and A11pl3Z, approaches from the direction of the constellation Sagittarius, traveling at an impressive radial velocity of about 58 km (36 miles) per second.
3I/ATLAS passed near Mars at a distance of 0.194 AU on October 3 and reached its closest encounter with the Sun, known as perihelion, on October 30.
On March 16, 2026, this interstellar visitor will approach Jupiter at a distance of 0.357 astronomical units.
“Hubble tracked a comet across the sky,” they stated.
“As a result, the background stars appear as streaks of light.”
“Hubble had previously observed 3I/ATLAS in July, shortly after its discovery, and several NASA missions have also studied the comet since then.”
“Observations are expected to persist for several more months as 3I/ATLAS journeys out of the solar system.”
“This image displays a teardrop-shaped glowing halo extending toward the sun,” stated Harvard University Professor Avi Loeb about the new Hubble images.
“This extension of the tail toward the sun was also noticeable in the pre-perihelion Hubble images taken on July 21, where 3I/ATLAS was approaching the Sun from a distance 56% greater than that of Earth.”
“The new radius of the glow is estimated to be around 40,000 km (24,855 miles), with its retro tail extension reaching approximately 60,000 km (37,282 miles).”
“In recent papers, I suggested that the coma teardrops in the 3I/ATLAS post-perihelion images are linked to numerous macroscopic non-volatile objects that have separated from the Sun due to measurements of non-gravitational accelerations moving away from the Sun,” he elaborated.
“I predicted that if the object overlapped with 3I/ATLAS at perihelion, by November 30th, the swarm would be about 60,000 km closer to the Sun than 3I/ATLAS.”
“This separation aligns perfectly with the teardrop-shaped anti-caudal extension visible in the new Hubble image.”
Comet 3I/ATLAS is the third known visitor from beyond our solar system
International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist; J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab)
The interstellar comet 3I/ATLAS releases carbon-rich compounds at a higher rate than most comets in the solar system, including methanol. This compound plays a crucial role in prebiotic chemistry and is not commonly found in other interstellar objects.
Having made only three known visits to our solar system, 3I/ATLAS stands apart from comets found in our galactic neighborhood. While approaching the Sun, it developed a crust of water vapor and gas, containing significantly more carbon dioxide than typically found in Solar System comets. Additionally, the comet’s light appeared unusually red, hinting at atypical surface chemistry, and it began emitting gas well before reaching the Sun. This could indicate that it has not approached another star in hundreds of millions of years, or possibly since leaving its home system.
Recently, Martin Cordiner and a team using the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile discovered that 3I/ATLAS generates significant amounts of hydrogen cyanide gas, as well as even larger quantities of gaseous methanol. “Hydrogen cyanide and methanol are usually found in trace amounts and aren’t dominant components in our comets,” explained Cordiner. “However, they appear to be notably abundant in this alien comet.”
Cordiner’s research team observed that the hydrogen cyanide comes from near the comet’s core, producing around a quarter to half a kilogram per second. Methanol was also found in the core, indicating large quantities are produced even within the comet’s coma, which is the extensive trail of dust and gas extending miles away from the comet itself.
Methanol is emitted at approximately 40 kilograms per second, significantly more than hydrogen cyanide, which represents about 8 percent of the total vapor released (compared to roughly 2 percent from typical solar system comets). The different locations of these two molecules suggest that the comet’s core may not be uniform, which could provide insights into how comets are formed, according to Cordiner.
Cordiner noted that, while methanol is a relatively straightforward carbon-based compound, it plays an essential role in forming more complex molecules critical for life. Its production appears to be high when chemical reactions producing these larger molecules occur. “Chemically, it seems unlikely that we can progress toward highly complex substances without generating methanol,” Cordiner said.
Josep Trigo-Rodriguez and colleagues from Spain’s Institute of Space Sciences suggested that comets with substantial iron and metals are likely to produce considerable methanol as well. The presence of liquid water heated by the Sun could permeate the comet’s core and engage in chemical reactions with its iron, resulting in methanol production. Thus, discovering methanol in the coma might indicate a metal-rich composition of the comet, he adds.
NASA’s Psyche spacecraft has obtained fresh images of 3I/ATLAS, marking it as the third astronomical object and the second comet observed from outside our solar system.
Psyche secured four observations of 3I/ATLAS over an 8-hour period on September 8 and 9, 2025. Image credit: NASA/JPL-Caltech/ASU.
3I/ATLAS was found on July 1, 2025, by the ATLAS survey telescope located in Rio Hurtado, Chile.
The orbits of interstellar comets represent the most dynamically extreme pathways of any astronomical object recorded within our solar system.
Known also as C/2025 N1 (ATLAS) and A11pl3Z, 3I/ATLAS reached its closest point to the Sun on October 30, 2025.
The latest images of the comet were captured during an eight-hour window on September 8 and 9, 2025, when 3I/ATLAS was roughly 53 million kilometers (33 million miles) away from NASA’s Psyche spacecraft.
“The observations collected by the mission’s multispectral imager will assist in refining the trajectory of 3I/ATLAS,” stated members of the Psyche team.
“Psyche’s multispectral imager consists of a pair of identical cameras fitted with filters and telephoto lenses to photograph the surface of the metal-rich asteroid Psyche across various wavelengths of light.”
“During these observations, Comet 3I/ATLAS was moving away from the spacecraft, but the imager’s sensitivity to the comet’s reflected sunlight allowed for accurate tracking of the object.”
The recent observations further illuminate the faint coma—a cloud of gas and dust—surrounding 3I/ATLAS’ core, which is a frozen mixture of ice and rock.
“Psyche will collaborate with numerous other NASA missions to track the positions of comets over time, aiding astronomers in comprehending the movement of such objects within our solar system,” researchers stated.
“Though comets do not pose a direct threat to Earth, NASA’s space missions contribute to ongoing efforts to discover, monitor, and better understand objects in our Solar System.”
NASA’s STEREO (Solar-Earth Relations Observatory), the NASA/ESA SOHO (Solar-Heliospheric Observatory), and NASA’s PUNCH (Corona-Heliosphere Integrating Polarimeter) missions had the extraordinary capability to observe sky regions near the Sun, enabling them to monitor 3I/ATLAS as it traversed behind the Sun from Earth’s perspective.
3I/ATLAS moves at an incredible speed of 209,000 km (130,000 miles) per hour, visualized through a series of colorized stacked images captured from September 11 to 25, 2025, using the Heliocentric Imager-1 instrument aboard NASA’s STEREO-A spacecraft. Image credit: NASA / Lowell Observatory / Qicheng Zhang.
STEREO monitored the interstellar comet 3I/ATLAS between September 11 and October 2, 2025.
The mission aims to examine solar activity and its effects on the entire solar system and is part of a collection of NASA spacecraft studying comets, offering insights on their size, physical characteristics, and chemical makeup.
Initially, it was believed that comet 3I/ATLAS would be too dim for STEREO’s instruments, but advanced image processing using the visible-light telescope Heliospheric Imager-1 and the stacking of images revealed 3I/ATLAS effectively.
By overlaying multiple exposures, distinct images were produced, showing the comet slightly brighter at the center.
This image of 3I/ATLAS combines observations from the NASA/ESA SOHO mission between October 15 and 26, 2025. Image credit: NASA / ESA / Lowell Observatory / Qicheng Zhang.
The SOHO spacecraft managed to catch a glimpse of 3I/ATLAS from October 15 to 26, 2025.
During this time frame, the LASCO instrument suite onboard SOHO identified comets crossing its observation area from around 358 million km (222 million miles) away, which is more than twice Earth’s distance from the Sun.
SOHO orbits at Sun-Earth Lagrange Point 1, a gravitational equilibrium point approximately 1.6 million km (1 million miles) closer to the Sun along the Sun-Earth axis.
Members of the SOHO team also utilized stacking techniques to create images of 3I/ATLAS.
In this image, 3I/ATLAS is clearly visible as a bright object in the center, created by consolidating observations from NASA’s PUNCH mission conducted from September 20 to October 3, 2025. Image credit: NASA/Southwest Research Institute.
The PUNCH mission observed 3I/ATLAS from September 20 to October 3, 2025.
These observations indicated that the comet’s tail extended slightly to the lower right.
During this period, the comet was so dim that the PUNCH team was uncertain if the spacecraft would be able to detect it well, given its primary focus on studying the Sun’s atmosphere and solar wind rather than comets.
However, by collecting multiple observations, 3I/ATLAS and its tail became distinctly visible.
“We’re truly pushing the limits of this system,” stated Dr. Kevin Walsh, a planetary scientist at the Southwest Research Institute who led the PUNCH observations of comets.
This image of 3I/ATLAS was captured by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter on October 2, 2025. Credit: NASA / JPL-Caltech / University of Arizona.
On October 2, 2025, the Mars Reconnaissance Orbiter (MRO) observed 3I/ATLAS from approximately 30 million km (19 million miles) away.
The MRO team utilized the High-Resolution Imaging Science Experiment (HiRISE), which typically focuses on the Martian surface.
By maneuvering, the spacecraft can direct its camera toward other celestial objects. This method was previously employed in 2014 when HiRISE collaborated with MAVEN to examine the comet Siding Spring.
“Observations of interstellar objects are still infrequent, so each time we learn something new,” noted Dr. Shane Byrne, HiRISE principal investigator and researcher at the University of Arizona.
“We were fortunate that 3I/ATLAS came close to Mars.”
Captured at a resolution of about 30 km (19 miles) per pixel, 3I/ATLAS appears as a pixelated white sphere in the HiRISE images.
“This sphere is a cloud of dust and ice, referred to as a coma, that the comet emits as it travels past Mars,” the researchers added.
Further analysis of HiRISE images could assist scientists in establishing an upper limit on the size of a comet’s core, composed of ice and dust.
The images might also uncover properties of particles known as comas within the comet’s atmosphere.
Ongoing scrutiny of the images may reveal nuclear fragments and gas jets expelled as comets disintegrate over time.
“One of MRO’s greatest contributions to NASA’s Mars research is its ability to observe surface phenomena that only HiRISE can detect,” explained Dr. Leslie Tampali, MRO’s project scientist and a research scientist at NASA’s Jet Propulsion Laboratory.
“This opportunity allows us to study passing space objects.”
“Thanks to NASA’s versatile fleet of spacecraft throughout our solar system, we can continue to observe this dynamic entity from unique perspectives,” stated Georgia Tech researcher Professor James Ray, a HiRISE co-investigator.
“All three prior interstellar objects exhibit significant differences from one another and from typical Solar System comets, making every new observation incredibly valuable.”
“Being able to observe a visitor from another star system is extraordinary in itself,” remarked Dr. Tomás Díaz de la Rubia, senior vice president for research and partnerships at the University of Arizona.
“Doing so from a University of Arizona-led instrument orbiting Mars adds to its remarkable nature.”
“This moment highlights the ingenuity of our scientists and the lasting impact of this university’s leadership in space exploration.”
“HiRISE exemplifies how discovery tools can benefit both science and the public interest.”
NASA unveiled new images of an interstellar comet on Wednesday, marking it as the third confirmed visitor from elsewhere in the galaxy. The visuals depict the comet as a luminous point encircled by a halo of gas and dust.
In the eagerly awaited photograph, the comet, designated 3I/ATLAS, mainly appears as an illuminated spot, though its tail can be seen as a faint elongated streak in some frames.
Interstellar comet 3I/ATLAS (highlighted in the center) as captured by NASA’s Lucy spacecraft. This image was formed by combining multiple photos taken on September 16, as the comet approached Mars. NASA / Goddard / SwRI / JHU-APL
First identified in July, comet 3I/ATLAS has generated significant excitement among scientists and astronomy enthusiasts. The fascination arises from the unique chance to observe interstellar objects at such proximity.
The latest images were captured by an array of NASA spacecraft while the enigmatic comet circled through the inner solar system from late September to mid-October. The release was delayed due to a government shutdown that interrupted operations at NASA and other federal institutions.
The NASA missions responsible for these new images include the PUNCH satellite, which observes the Sun, the Solar Heliosphere Observatory, the MAVEN mission studying Mars’ atmosphere, and the Perseverance rover, currently on Mars’ surface.
Traveling at 130,000 miles per hour, the comet 3I/ATLAS was depicted in a series of colorized stacked visuals from September 11 to 25 using the STEREO-A (Solar Terrestrial Relations Observatory) visible-light camera. NASA / Lowell Observatory / Zhang Qicheng
Prior to 3I/ATLAS, the only confirmed interstellar objects to have entered our solar system were the cigar-shaped ‘Oumuamua in 2017 and comet 2I/Borisov in 2019.
The arrival of 3I/ATLAS in our cosmic vicinity has sparked wild speculations about the possibility of it being extraterrestrial technology or an alien spacecraft, although no scientific backing supports these ideas. NASA officials stated in a press conference on Wednesday that all current observations align with known comet characteristics.
“We certainly haven’t detected any technosignatures or anything that would suggest it is anything but a comet,” remarked Nicki Fox, associate administrator for NASA’s Science Mission Directorate.
Nonetheless, the comet’s interstellar roots indicate it possesses intriguing attributes that could yield new insights regarding star systems beyond our own, according to Fox.
“That difference is particularly fascinating to us,” she stated. “It may have existed before our solar system was formed. That’s pretty exciting.”
In the forthcoming weeks, scientists will have enhanced opportunities to study 3I/ATLAS and further analyze its appearance, speed, chemical makeup, and potential origins.
“This is a new scientific chance and an opportunity to delve into the composition and history of other solar systems,” expressed Tom Statler, NASA’s lead scientist for small solar system bodies. “We’re just beginning to understand these types of objects and determining the right questions to pose about them.”
Comet 3I/ATLAS was documented by the PUNCH satellite in low Earth orbit from September 28 to October 10, when it was between 231 to 235 million miles away. NASA/Southwest Research Institute
However, tracing the comet’s origin remains challenging, Statler noted.
3I/ATLAS came closest to the Sun at the end of October and is currently continuing its path through the inner solar system. It has been so near to the Sun that it has not been visible to terrestrial telescopes recently, but NASA anticipates it will become visible again post-December.
On December 19, 3I/ATLAS is expected to make a close pass by Earth. Although it poses no threat, NASA states that the comet will remain about 170 million miles away during this encounter.
Statler indicated that the James Webb Space Telescope will observe the comet in December, while ground-based telescopes like the W.M. Keck Observatory in Hawaii are also scheduled to capture images of the comet in the future.
An image depicting interstellar comet 3I/ATLAS as it approached Mars, captured by the European Space Agency’s ExoMars Trace Gas Orbiter. European Space Agency
The photos released by NASA on Wednesday join a growing collection acquired by various spacecraft across the solar system. In early October, the European Space Agency shared 3I/ATLAS images taken by the ExoMars Trace Gas Orbiter, which showed a bright point moving through the vastness of space.
This spacecraft, co-managed by the ESA and the Russian Federal Space Agency, detected a comet approaching near Mars at that time, about 18.6 million miles away according to ESA.
NASA continues to analyze additional data gathered by the fleet of spacecraft since early October.
“There’s much more to come,” Statler remarked. “Not all data has been transmitted through NASA’s Deep Space Network yet, and there are numerous observations still planned.”
Recent observations of 3I/ATLAS, the third interstellar object confirmed to traverse the solar system following 1I/Oumuamua and 2I/Borisov, reveal a sophisticated multi-jet configuration.
The image of 3I/ATLAS was captured by Lowell Observatory astronomer Qicheng Zhang on October 31, 2025. Image credit: Qicheng Zhang / Lowell Observatory.
Discovered on July 1, 2025, by the NASA-funded ATLAS (Asteroid Terrestrial Impact Last Alert System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is also referred to as C/2025 N1 (ATLAS) and A11pl3Z.
Originating from the direction of the Sagittarius constellation, this comet holds the designation of being the most dynamically extreme object recorded, characterized by its hyperbolic orbit with high eccentricity and extreme hyperbolic velocity.
3I/ATLAS came closest to the Sun, reaching perihelion, on October 30, 2025.
This interstellar visitor approached within 1.4 AU (astronomical units), or approximately 210 million km, of the Sun, which is just inside Mars’ orbit.
At perihelion, the comet traveled at a remarkable speed of about 68 km/s, and its proximity to the Sun temporarily rendered it invisible to Earth’s telescopes.
Following perihelion, it will once again be observable through telescopes until December as it gradually distances itself from both the Sun and Earth, returning to interstellar space.
The initial post-perihelion optical image of 3I/ATLAS (as shown above) was captured. This was announced on October 31 by astronomer Zhang Qicheng of Lowell Observatory using the Discovery Telescope.
This image of 3I/ATLAS was taken on November 8, 2025 by astronomers from the ICQ Comet Observation Group. Image credit: M. Jaeger / G. Lehmann / E. Prosperi.
On November 8th, three astronomers from the ICQ Comet Observation Group observed the comet situated 29 degrees from the Sun in the sky.
The images they captured depict a complex jet structure with at least seven jets, including several anti-tail planes.
“Given the multitude of jets emerging in various directions, the noted non-gravitational acceleration of 3I/ATLAS implies that more than 10 to 20 percent of its initial mass would need to be ejected near perihelion,” remarked Professor Avi Loeb of Harvard University discussing the ICQ images. He stated,
“Only a small fraction of this mass carries the necessary momentum in the favored direction.”
“Consequently, the debris cloud enveloping 3I/ATLAS likely constitutes a considerable portion of the comet’s original mass.”
This 3I/ATLAS image was taken on November 9, 2025, by astronomers from the British Astronomical Society. Image credit: Michael Buechner / Frank Niebling.
On November 9th, two astronomers from the British Astronomical Association (BAA) studied the comet using two telescopes.
Their combined image displayed a long “smoking” tail along with two anti-tail jets.
“3I/ATLAS is expected to make its closest approach to Earth on December 19, 2025, making the multijet structure an intriguing target for future observations with the Hubble and Webb telescopes,” Professor Loeb mentioned discussing the BAA images. He noted.
The minimum distance to Earth will be 269 million km, roughly 100 times the extent of the jet structure illustrated in the image.
This striking image of 3I/ATLAS was taken by the International Gemini Observatory in Chile, revealing the comet’s coma formed of gas and dust.
Image Credit: International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist
3I/ATLAS, an interstellar comet traversing our solar system, presents a challenge in determining its origin due to potential alterations from cosmic rays over billions of years that could have completely transformed its characteristics.
Initially detected in July, astronomers have begun to analyze its intriguing traits, including its coma, which features carbon dioxide levels at least 16 times greater than standard comets in our solar system, marking it as one of the most CO2-rich comets ever seen.
While some researchers theorized that this might indicate an unusual star system as the comet’s birthplace (or, less plausibly, a link to extraterrestrial life), a more straightforward explanation has emerged.
Roman Maggiolo and colleagues from the Belgian Royal Institute for Astronautics and Aeronautics assert that the elevated CO2 concentrations are likely a result of significant alterations to the outer layers of 3I/ATLAS over billions of years due to cosmic rays.
“This slow process has often been neglected or underestimated, yet it profoundly impacts objects like comets and interstellar bodies,” Maggiolo states.
The team compared their findings from 3I/ATLAS to lab experiments that simulate cosmic ray bombardment of ice composed of water and carbon monoxide, akin to that found on comets. These experiments revealed that this process generates substantial CO2 and leaves behind a carbon-rich residue that aligns with observations from the comet.
“Gradually, cosmic rays create reactive radicals—molecular fragments that break down and reform, thereby altering the ice’s chemical makeup,” Maggiolo explains.
This revelation poses a setback for comprehending the origins of comets, as cosmic rays can obliterate critical evidence. Previously, astronomers thought interstellar comets like 3I/ATLAS were remarkably preserved, acting as cold fossils with vital data about other star systems; however, a more cautious approach may now be necessary concerning the insights they can provide.
Although its swift passage through the solar system limits the chances for satellites to explore and directly sample these comets, there remains a sliver of hope for clarifying the true nature of 3I/ATLAS.
Currently, the comet is nearing the Sun and isn’t visible from Earth but is anticipated to resurface in December. This close encounter might result in sufficient melting of the outer ice layer to unveil materials shielded from cosmic rays, as noted by Maggiolo. However, this is contingent upon how much ice has already vanished since its entry into the solar system and the thickness of the icy crust, details that are still unclear.
Cyriel Opitum, a professor at the University of Edinburgh in the UK, emphasizes that forthcoming observations utilizing both the James Webb Space Telescope and ground-based telescopes will be essential in uncovering primitive material beneath the comet’s surface. “We are looking forward to an exciting few months ahead,” she states.
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Interstellar comet 3I/ATLAS captured by the Gemini South Telescope in Chile
International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist; J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), TA President (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab)
The interstellar object 3I/ATLAS is acting oddly once more. This foreign visitor from another star is now obscured by the sun’s shadow, leading some to speculate about its secretive nature. The only likely explanation, they whisper, is that it’s an alien spacecraft.
This notion, however, is utterly baseless. It simply doesn’t hold up that a spacecraft would choose to stay hidden for just a few days while previously visible and likely to be so again. If this were actually a stealthy spacecraft, then the aliens piloting it would either be incredibly foolish or believe us to be.
How can we assert this? As an astronomer recently explained to me, if 3I/ATLAS is indeed a spacecraft, it’s doing a remarkable job of masquerading as a comet. This is what fuels the sensational discussions surrounding 3I/ATLAS (named after the eagle’s eye). planetary defense equipment (I first noticed it in July), which was both amusingly frustrating and clearly ridiculous. The evidence overwhelmingly indicates that it is a comet.
Let’s explore why. It possesses a coma, a shell of vaporized ice. It exhibits a luminous tail. Its trajectory can best be described as that of an icy projectile entering our solar system from beyond. So, why is it “hiding” behind the sun? It just reached perihelion, the closest point to our solar star in its voyage through our cosmic neighborhood. Every celestial voyager, from comets to asteroids, experiences perihelion. 3I/ATLAS happens to be behind the Sun, yet closest to it from Earth’s viewpoint.
There are certainly some intriguing aspects of 3I/ATLAS that excite astronomers. For instance, it contains a higher concentration of carbon dioxide ice compared to water ice. Nevertheless, it remains a comet, not a space probe. Some materials are composed of – hold on, aren’t those metals? Spaceships are built from metal! So, could 3I/ATLAS actually be a spacecraft? Absolutely not; we routinely observe metals in the rocky, icy cores of comets. In truth, numerous comet types exist in our solar system, many of which are indeed peculiar.
It was also somewhat unusual that at one point 3I/ATLAS had its dusty tail oriented toward the Sun instead of the opposite direction. Some speculated it was not the tail but rather a spacecraft’s exhaust plume attempting to decelerate. However, the issue is that 3I/ATLAS’s orbit is consistent with that of an interstellar comet; it’s not as if someone applied brakes to an interstellar probe. The unique orientation of its tail resulted from the specific icy, powdery particles released from its surface. This transient object would typically be pushed away from the sun by solar radiation pressure, but some of this comet’s material was so dense that it couldn’t be redirected and consequently rolled toward the sun.
3I/ATLAS is only the third interstellar object ever documented, so investigating its small population is likely to uncover some remarkable characteristics. ‘Oumuamua, the first identified interstellar visitor, was significantly stranger. Its shape was likely cigar-like, rapidly accelerating as it left the solar system. Yet even this oddity can be perfectly rationalized: it was a flashy comet-like entity. The next two interstellar objects, 2I/Borisov and 3I/ATLAS, also showcase interesting features. But to propose they are spacecraft rather than comets is equivalent to calling ice in the freezer a pineapple. You can certainly say that, but if you aim to convince me, you must present more substantial proof.
Many among us, myself included, eagerly anticipate the day we learn we’re not alone in the universe. Thus, it’s no wonder that people jump to the unfounded conclusion that 3I/ATLAS might signal that this long-awaited day has finally come. However, in an age rife with misinformation, to suggest, against overwhelming evidence, that this comet could be alien is not just misguided; it’s profoundly irresponsible.
The Orionid meteor shower will soon light up the night sky once again.
This year’s event is anticipated to be particularly stunning, as the peak of the Orionid meteor shower in 2025 aligns with the new moon night, making the sky notably darker.
You don’t require any special gear to observe meteor showers, making it an excellent introduction to stargazing. All you need are your eyes and a clear, dark sky.
Here’s all the essential information to enhance your viewing experience.
When is the Orionid meteor shower tonight?
The 2025 Orionid meteor shower will reach its peak during the night of October 21-22 in the US and UK, but you can catch glimpses of it from October to November.
This meteor shower is relatively prominent. Under optimal conditions, you might see 10 to 20 meteors each hour, though realistically you may spot one roughly every 10 minutes.
What makes the 2025 Orionids especially remarkable is the coincidence with the new moon, allowing for darker skies and visibility of fainter meteors.
Meteors can be seen throughout the night, but many fade below the horizon in the evening. For a better view, wait until after midnight when they will be higher in the sky.
However, the key factor in your viewing experience will be the weather. Keep an eye on the forecast for any breaks in the cloud cover. Even if conditions aren’t ideal, you might catch some meteors if the sky is partly clear.
Don’t fret if the weather doesn’t seem promising on the peak night. You should still see plenty of meteors around October 21st.
How can you see the Orionid meteor shower in 2025?
Meteor showers provide a wonderful shared experience—invite your friends and family! – Credit: Getty
The ideal way to observe a meteor shower is to venture to the darkest location available. Escaping the light pollution of urban areas is your best bet (ensure you have permission and stay in a safe area after dark).
If you can’t get out of the city, try to avoid any direct light sources, whether that’s at your local park or a corner of your garden shielded from streetlights by a fence.
Instead of focusing on one specific direction, aim to take in as much of the sky as possible. Sun loungers make it comfortable to lie back and gaze upwards without straining your neck. Remember to dress warmly and bring along some snacks.
Leave your telescope at home; for meteor watching, your eyes are the best tool you have.
Give your eyes about 20 minutes to adjust to the darkness. Be cautious—any brief exposure to bright light, including your phone, can reset this adjustment.
Now, keep looking up and be patient. Eventually, you should start to see meteors streaking across the sky.
What is a meteor shower?
The Orionid meteor shower is a result of Halley’s Comet, which orbits the inner Solar System approximately every 75 years (its next visit is slated for 2061). As the comet passes, it leaves behind a trail of dust and debris.
Every year, Earth passes through this debris stream, causing tiny particles to collide with our atmosphere at incredible speeds of 70 km (41 miles) per second. This collision heats up the air, creating bright flashes of light known as meteors or shooting stars.
Why are they called the Orionid meteor shower?
Orion is one of the brightest constellations visible in the northern sky – Credit: Getty
The shower derives its name from the fact that all meteors appear to radiate from the constellation Orion.
If you track an Orionid meteor’s path, you’ll find it leads back to this particular constellation.
Orion can be easily recognized by the three bright stars that form its well-known belt in the southern sky. If you’re unsure of what to look for, consider downloading a stargazing or astronomy app to assist you.
Additionally, you might spot meteors that do not originate from the Orion constellation. If so, congratulations! You’ve encountered a stray meteor that coincidentally entered Earth’s atmosphere during the shower.
For the first time, astronomers have witnessed the real-time formation of a ring system. This particular ring encircles Chiron, a comet-like entity that orbits the sun between Saturn and Uranus. Each time you observe Chiron, its rings will appear slightly varied.
While Chiron is not the first small celestial body to display rings, it joins the ranks of the asteroid Chariklo and the dwarf planets Haumea and Quaor, which also possess small ring systems. These rings were identified using a technique called stellar occultation, where observations are made as an object passes in front of a distant star, allowing scientists to create a map of how that star’s light is obstructed by the surrounding material.
“Only about 20 objects have been observed through stellar occultations, so having four of them identified with rings represents a robust statistic,” says Bruno Sicardi from the Paris Observatory in France. “Given the countless bodies in existence, it stands to reason that hundreds of ring systems should be out there.” He anticipates that more will be discovered in the years ahead.
Sicardi and his team analyzed the 2023 occultation of a star to decode the structure of the ring surrounding Chiron. While earlier findings hinted at the existence of three rings, the new observations reveal an extra disk of material encircling those rings, extending farther from Chiron’s surface, along with an entirely new ring previously unseen.
“Nature presents us with rings in their developmental stages, which is a fortunate scenario for us. Unlike the rings of Saturn, Uranus, or even Chariklo, which generally stay consistent, we are witnessing something dynamic,” Sicardi remarks.
Rings can form through various processes, and observing their formation can deepen our understanding significantly. As Christian Pereira from the National Astronomical Observatory of Brazil notes, “[This could] unveil the specific conditions that facilitate the formation, persistence, and eventual disappearance of rings, which may ultimately elucidate why such systems are typically found only in the frigid, icy areas of the solar system.”
The bright area represents the comet’s core, which consists of a dense mixture of ice, rock, and dust. Typically, the nucleus is enveloped in a cloud of gas and dust known as a coma.
Since being discovered in July, Comet 3i/Atlas has captivated both astronomers and space enthusiasts. There have been intriguing theories suggesting it could be alien technology or a spacecraft, though no scientific backing exists for these ideas.
The comet is not stationary.
Researchers tracking its trajectory project that the comet will make its closest approach to the sun around October 30, as its orbit navigates through the inner solar system in the following weeks.
NASA has stated that 3i/Atlas poses no risk to Earth, maintaining a distance of about 170 million miles during its pass.
However, its near pass of Mars provided a unique observational opportunity.
The ExoMars Trace Gas Orbiter, jointly run by the ESA and Russia’s Federal Space Agency, directed its cameras at the comet for approximately a week starting October 1, officials from ESA noted. At that point, 3i/Atlas was roughly 18.6 million miles from the spacecraft.
Despite this, the orbiter’s instruments are primarily designed for imaging the Martian surface rather than distant objects, as explained by Nick Thomas, principal investigator for the imaging system.
“This posed a significant challenge for our instruments,” he stated in a statement. “Comets are approximately 10,000 to 100,000 times less dense than typical targets.”
Other interstellar visitors to our solar system include Oumuamua in 2017 and 2i/Borisov in 2019.
ESA emphasized, “All celestial bodies in our solar system share a common origin, but interstellar comets are unique outsiders, providing insights into the formation of distant worlds.”
As 3i/Atlas travels through our solar system, astronomers are eager to analyze its size and physical characteristics. Earlier this year, it was visible through ground-based telescopes, but it’s currently too close to the sun for observation. It is expected to reappear on the opposite side of the sun by early December, according to NASA.
NASA is tracking 3i/Atlas with the Hubble Space Telescope and plans additional observations in the upcoming months. The James Webb Space Telescope, Spherex Space Observatory, Parker Solar Probe, and the Exoplanet Survey Satellite are among the instruments hoping to catch a glimpse of the comet.
A photo taken recently by the Saturday camera captured streaks of light, leading to speculation online that it could be Comet 3i/Atlas. However, NASA has not confirmed this, and their public information office is currently closed due to the government shutdown.
ESA’s Mars Express spacecraft did focus its camera on the comet as it passed, although further analysis will be required to distinguish interstellar objects from the gathered data.
Following 1i/oumuamua and 2i/borisov, 3i/atlas is the third object and has been confirmed as the second comet originating from outside the solar system.
This image from the Gemini North Telescope Multi-Object Spectrometer (GMOS-N) depicts the interstellar comet 3i/Atlas. Image credits: International Gemini Observatory/Noirlab/NSF/Aura/K. Meech, Ifa&U. Hawaii / Jen Miller & Mahdi Zamani, Noirlab.
The comet 3i/Atlas was identified on July 1, 2025, by the Asteroid Land Impact Trastor Alt System (ATLAS), a project supported by NASA.
Also referred to as C/2025 N1 (ATLAS) and A11PL3Z, the comet is approaching from the direction of Sagittarius.
Its orbit is the most dynamically extreme among the objects documented within the solar system.
“While aliens may not be the first to engage with us, 3i/Atlas has much to teach us, as it is merely the third recorded interstellar entity to traverse our solar system,” stated Jacqueline McClary, an astronomer at Northeastern University.
“All comet-like interstellar bodies are unique in that they are the only ones that have provided us with physical observations coming from outside our solar system. They serve as messengers from afar.”
“Given how rare it is to detect interstellar objects within our solar system, each discovery is distinct,” remarked Adina Feinstein, an astronomer at Michigan State University.
“3i/Atlas presents an opportunity to examine other solar systems closely, without the necessity of traveling to them.”
From the moment 3i/Atlas was observed, it was evident that it deviated from typical comet behavior. Initially, it appeared to emit an unusual light.
Comets are generally very dark, which makes them challenging for astronomers to detect initially.
As they near the sun, solar radiation prompts volatile compounds and ice to sublimate from their surfaces.
This process leads to the formation of a coma, which ultimately evolves into the iconic tail associated with comets across the night sky.
“Jupiter is positioned 5 AU from the Sun, and most comets need to approach closer for solar radiation to generate enough intensity to form this melted tail,” Dr. McClary said.
“Comet 3I/Atlas developed its coma at a considerably greater distance than typical, remaining beyond Jupiter’s orbit.”
3i/Atlas began to emit light far from the sun, prompting initial speculation that it could be an extraterrestrial spacecraft. What else could emit light so rapidly?
However, later observations suggested that it not only possesses a comet-like tail but is also rich in carbon dioxide.
The NASA/ESA/CSA James Webb Space Telescope has ultimately unveiled that comets are remarkable for attributes beyond their interstellar heritage.
Not only was it composed primarily of carbon dioxide, but it also exhibited an extraordinary ratio of carbon dioxide ice to water ice, the best ever documented.
This discovery allows for insight into the conditions that prevail in other solar systems and how such systems were initially formed.
“Clearly, the parent system of 3i/Atlas may have had a wealth of carbon dioxide, or perhaps a unique radiative process occurred that led to the depletion of other materials, leaving abundant carbon dioxide,” Dr. McClary remarked.
“By understanding the composition of this comet and comparing it with other interstellar comets, we gain insight into solar system formation across different environments.”
The precise origin of 3i/atlas remains elusive.
“It likely hails from the Milky Way’s bulge, but pinpointing its exact source will be challenging,” Dr. McCleary commented.
“For it to have escaped its parent solar system, the comet must have undergone a gravitational disturbance that altered its trajectory, setting it on its current path into the solar system.”
Nevertheless, scientists have gained a more intricate understanding of the comet, having observed it crossing Jupiter’s orbit since October, elucidating more about its characteristics.
The Juno satellite orbiting Jupiter is ideally suited to observe these interstellar visitors.
“We may be able to observe this comet with remarkable clarity. It could prove particularly intriguing as it nears the sun, causing significant carbon dioxide vaporization, so we can assess what remains,” Dr. McClary stated.
Gaining more knowledge about 3i/Atlas assists not only in comprehending the nature of other solar systems, but also in exploring the conditions under which sentient life might arise, given the uniqueness of our solar system.
“This serves as a window into the primitive materials of other solar systems, which is invaluable for refining models of solar system formation,” Dr. McCullilia said.
“Is our solar system common or rare? It appears to be relatively uncommon, offering us a way to quantify its uniqueness.”
“Investigating other solar systems places humanity in a broader context,” Dr. Feinstein remarked.
“One of the most profound questions we face is, are we alone in the universe? Each NASA mission brings us a step closer to answering this monumental question.”
“Capturing numerous observations of these interstellar objects, especially as they approach the sun, is crucial for understanding their behaviors,” noted John Noonan, an astronomer at Auburn University.
“These interstellar objects may not have been significantly warmed in millions, if not billions, of years, making it fascinating to study how they react to early thermal exposure.”
Researchers at the Southwest Research Institute have completed a study outlining how the proposed spacecraft could fly by interstellar comets, offering valuable insights into properties of these bodies throughout the solar system. Leveraging recent findings from interstellar comet 3i/Atlas, they explored mission concepts and concluded that the proposed spacecraft could potentially intercept and observe 3i/Atlas.
Hubble captured this image of 3i/Atlas when it was 446 million km (277 million miles) from Earth on July 21, 2025. Image credits: NASA/ESA/David Jewitt, UCLA/Joseph Depasquale, Stsci.
In 2017, interstellar object 1i/’oumuamua became the first interstellar comet identified within the solar system.
Following that, the second interstellar comet, 2i/Borisov, was discovered in 2019, and recently, 3i/Atlas was identified this year.
“These novel types of objects present the first true opportunity for humanity to closely examine bodies formed in other star systems,” said Dr. Alan Stern, a planetary scientist at the Southwest Research Institute.
“Flybys of interstellar comets could yield unparalleled insight into their composition, structure, and characteristics, significantly enhancing our understanding of the solid body formation process in diverse star systems.”
Scientists estimate that numerous interstellar objects from distant origins cross Earth’s orbit each year, with up to 10,000 potentially entering Neptune’s orbit in certain seasons.
Dr. Stern and colleagues tackled unique design challenges while defining the costs and payload requirements for interstellar comet missions.
The hyperbolic trajectories and high velocities of these bodies present challenges for current avoidance methods, but this study indicated that Flybee reconnaissance is both feasible and cost-effective.
“The trajectory of 3i/Atlas falls within the intermittent range of missions we designed, and the scientific observations taken during such flybys would be groundbreaking,” stated Dr. Matthew Freeman from the Southwest Institute.
“The proposed mission would involve a rapid, frontal flyby, allowing us to gather substantial valuable data while also serving as a blueprint for future missions to other interstellar comets.”
The research establishes a significant scientific objective for its mission targeting interstellar comets.
Understanding the physical characteristics of a body sheds light on its formation and evolution.
Investigating the composition of interstellar comets may aid in explaining their origins and how evolutionary forces have shaped them since their inception.
Another objective is to thoroughly examine the coma of an object, the escaping atmosphere emanating from its center.
To devise mission orbital options, researchers created software to generate representative synthetic populations of interstellar comets, calculating the minimum energy trajectories from Earth to each comet’s pathway.
Software analyses have indicated that low-energy rendezvous trajectories are achievable, often requiring fewer resources during launch and flight compared to other solar system missions.
Scientists utilized the software to determine the trajectory the proposed spacecraft may have taken from Earth to intercept 3i/Atlas.
They found that the mission could potentially have reached 3i/Atlas.
“It’s incredibly promising regarding the emergence of 3i/Atlas,” noted Dr. Mark Tapley, an orbital mechanics expert at the Southwest Research Institute.
“We have demonstrated that there’s no need to launch any existing technology or mission frameworks that NASA has already employed to engage these interstellar comets.”
Astronomers utilized a Gemini Multi-Object Spectrometer (GMO) at the Gemini South Telescope, part of the NSF’s International Gemini Observatory in the Chilean Andes, to capture new multi-color images of the interstellar comet 3i/Atlas.
This image of 3i/Atlas was captured by the Gemini Multi-Object Spectrograph (GMO) on August 27, 2025 at the Gemini South Telescope. Image credit: International Gemini Observatory / NSF / AURA / Shadow The Scientist / J. Miller Array / M. M. Rodriguez, nsf/crask of rects Anchorage & Noirlab/M. Zamani, NSF’s Noirlab.
3i/Atlas was identified on July 1, 2025, by a NASA-supported Atlas (Asteroid Ground Shock Last Alert System) Survey Telescope in Riojartad, Chile.
The comet is anticipated to approach the Sun at a distance of 1.4 AU (210 million km, or 130 million miles) around October 30, 2025.
The latest images from Gemini/GMOS reveal a broad coma and tail extending roughly 1/120th of a degree across the sky, away from the Sun.
These features appear significantly more pronounced compared to earlier images of the comet, indicating that 3i/Atlas is becoming increasingly active as it traverses the inner solar system.
Recent observations also imply that the dust and ice from the comet closely resemble those of solar comets, suggesting a commonality in the processes that govern the formation of planetary systems around other stars.
“As 3i/Atlas journeys back into the depths of interstellar space, these images serve as both scientific milestones and enigmatic clues,” states Dr. Karen Meech, an astronomer from the Institute of Astronomy at the University of Hawaii.
“They remind us that our solar system is merely a fragment of a vast, dynamic galaxy, where even transient visitors can leave a lasting impact.”
Alongside capturing a stunning image, the primary scientific aim of the observation session was to obtain the comet’s spectrum, which corresponds to the wavelengths of the emitted light.
The resulting spectra provide critical insights into the composition and chemistry of the comet, enabling scientists to understand its changes as it navigates through the solar system.
“The main goal was to observe the color of the comet to glean information about the composition and size of the coma dust particles, as well as to obtain the spectrum for direct chemical analysis,” noted Dr. Mace.
“We were thrilled to witness the growth of the comet’s tail and to see our first hints of chemistry from the spectrum, indicating particle changes since earlier Gemini observations.”
“These observations yield both awe-inspiring visuals and invaluable scientific data,” asserts Dr. Bryce Bolin, a researcher at Eureka Scientific.
“Each interstellar comet acts as a messenger from another stellar system, and by examining its light and color, we can begin to appreciate the diversity of worlds beyond our own.”
Infrared images of 3I/Atlas taken by the James Webb Space Telescope
NASA/James Webb Space Telescope
3I/Atlas, an interstellar visitor, is noted for being one of the most carbon-rich comets observed, suggesting a formation in an environment vastly different from our solar system.
Since July, astronomers have been monitoring 3I/Atlas. While many findings indicate it resembles typical comets, several peculiar features hint at a more exotic origin, including the emission of water gas at distances from the sun typically unobserved in solar system comets.
Martin Codinner from NASA’s Goddard Space Flight Center in Maryland, along with his team, has utilized the James Webb Space Telescope to capture some of the most intricate observations of the comet.
Codinner’s team studied 3I/Atlas in early August, when they were approximately three times the distance from the sun compared to typical comets. At this distance, temperatures rise enough for water to transition from ice to gas, resulting in comets usually generating water vapor and dust, known as a coma.
However, their findings revealed that the coma of 3I/Atlas contains a significantly higher amount of carbon dioxide relative to water, with an 8:1 ratio. This is 16 times more than what is generally seen in other comets from our solar system at this distance from the Sun.
High carbon dioxide levels could imply that comets formed in planetary systems where carbon dioxide ice is more prevalent than water ice, suggests Matthew Genge from Imperial College London. “This may indicate a fundamental difference in planetary system formation compared to ours,” Genge adds.
When planetary systems initially form, there are differing quantities of dust, gas, and water vapor found at varying distances from stars. Over time, stars expel gas, leaving behind solid materials. If the progenitor star of 3I/Atlas expelled water vapor from locations where comets developed earlier than in our solar system, it could account for its unique composition, Genge articulates.
The scarcity of water vapor may also be attributed to previous close encounters with other stars, Genge notes. Codinner offers that water could be concealed deep within the comet’s crust, thus insulated from higher temperatures, which is indeed unusual.
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Hubble Space Telescope Image of Interstellar Comet 3i/Atlas. The telescope tracked the comet, causing background stars to appear as streaks.
NASA, ESA, David Jewitt (UCLA)/Joseph DePasquale (STScI)
The telescope’s observations of the Interstellar Comet 3i/Atlas have shown it resembles a comet found beyond our solar system. Intriguing aspects, like the substantial amounts of water detected even far from the sun, may shed light on the ancient stellar system from which it originated.
Objects from other solar systems that pass through ours are extremely rare. Discovered in July, 3i/Atlas is the third such interstellar visitor, following Oumuamua in 2017 and Borisov in 2019. Remarkably, its visit has only been a few months long.
Scientists speculate that its high speed may indicate that it originates from a star system billions of years older than our own. Initial estimates suggested it has a diameter of approximately 20 kilometers, but details about the extensive plume of water and gas remain limited.
Toni Santana Ross from the University of Barcelona and colleagues have utilized ground-based telescopes to observe the comet and its tail, finding it contains moderate amounts of dust. Notably, the dust appears to increase as the comet approaches the sun, mirroring patterns seen in comets from our outer solar system. “It’s a typical object; there’s nothing particularly strange about it,” states Santana Ross.
Astronomers have also monitored comets via space. Researcher collaborating found that the Hubble Space Telescope might estimate the comet’s size between 320 meters and 5.6 kilometers, and it likely started off much smaller.
Comets usually contain ice, which vaporizes as they near the sun, creating water vapor in their tails. Utilizing the Neil Gehrels Swift Observatory Satellite, Zexi Xing from Auburn University has detected water in the comet’s tail located significantly farther from the sun than is typical for comets. The amount of water detected suggests that about 20% of the comet’s surface is responsible for this production, exceeding typical solar system comet proportions.
Such prolific water generation may indicate that 3i/Atlas originates from a star system much older than ours, hypothesizes Cyrielle Opitom at the University of Edinburgh. This is due to older stellar systems generally having higher water content compared to other molecules. “It might be that because it formed earlier, it retains more water than other molecules, but it’s premature to reach a conclusion,” she remarks.
Astronomers are also scouring historical data to determine if the telescope mistakenly detected a comet. Adina Feinstein and her team at Michigan State University have found that the transit exoplanet survey satellite (TESS) was operationally searching for planets around other stars and incidentally captured a comet between May 7 and June 3. “It just happened that we were observing the exact region where 3i/Atlas was at that moment,” says Feinstein.
The comet was found to be surprisingly bright at that time, suggesting it was releasing significant amounts of water or gas even at considerable distances from the sun. “We didn’t detect transits in regions of our solar system where water would typically start to react,” highlights Feinstein.
In this distant region, the likelihood of finding water is low, with gases such as carbon monoxide and carbon dioxide being more common, according to Opitom. “This is a pattern seen in comets from our solar system; they can exhibit activity at much greater distances due to these volatile materials.”
Yet, the fact that it was active so far from the sun could indicate that this comet has not been significantly exposed to starlight throughout its life, notes Matthew Jenge from Imperial College London.
“What this implies is that this comet was ejected from the fringes of another solar system,” Genge describes. While the exact cause of its ejection is uncertain, it’s possible that gravitational forces from a nearby star could have set it on a trajectory towards us, he explains.
Opitom mentions that the James Webb Space Telescope has recently conducted its observations and that astronomers will analyze the data in the upcoming weeks, promising more insights into 3i/Atlas soon.
As comets approach their closest point to the sun in October, astronomers will have the opportunity to measure the gases they emit. This will provide important insights not only into the characteristics of the comet itself but also into the composition of the molecules in its active tail, which may reveal details about the formation of 3i/Atlas, according to Opitom.
Similar to previous interstellar objects, speculations about potential alien technology exist, but Santana Ross has found no supporting evidence. “If you take a holiday photo and see something tall with a long neck and four legs, you might think of it as an alien, but it’s most likely a giraffe,” he quips. “There’s no reason to believe this is anything unusual or evidence of something extraordinary.”
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Recent analysis of new images from the NASA/ESA Hubble Space Telescope reveals that the nucleus of 3i/Atlas measures between 320 m (1,000 ft) and 5.6 km (3.5 miles).
Hubble captured this image of 3i/Atlas, which was located 446 million km (277 million miles) from Earth on July 21, 2025. Image credits: NASA/ESA/David Jewitt, UCLA/Joseph Depasquale, Stsci.
3i/Atlas was discovered on July 1, 2025, by the Asteroid Land Impact Trastor Alt System (ATLAS) funded by NASA.
Its orbit is the most dynamically extreme among recorded solar system objects.
New observations from Hubble have provided astronomers with a more precise estimation of the comet’s solid icy nucleus size.
“The maximum diameter of the nucleus is 5.6 km, but it averages around 320 m,” stated David Jewitt, an astronomer from UCLA, along with his colleagues.
“Hubble’s images offer tighter constraints on the nucleus’s size compared to earlier ground-based measurements, although the solid core of the comet is not currently visible directly even with Hubble.”
“Data from other NASA missions, like Webb, TESS, Neil Gehrels Swift Observatory, and WM Keck Observatory, will further enhance our understanding of comets, including their chemical composition.”
Hubble also detected indications of dust plumes ejected from the sun-warmed side of the comet, along with dust tails drifting away from the nucleus.
The new findings indicate a dust loss velocity that aligns with the first comet observed at roughly 480 million km (300 million miles) from the Sun.
This behavior closely resembles the characteristics of a previously seen sun-bound comet observed within our solar system.
A notable difference is that this interstellar visitor originates from planetary systems beyond our Milky Way galaxy.
3i/Atlas speeds through the solar system at an astonishing rate of 209,000 km (130,000 miles) per hour, marking the highest speed ever recorded for visitors to our solar system.
This remarkable velocity indicates that comets have been traversing interstellar space for billions of years.
The gravitational pull from countless stars and nebulae has contributed to its increased speed.
The longer 3i/Atlas journeys through space, the faster it moves.
“No one knows the origin of this comet; it’s like catching a glimpse of a bullet for a thousandth of a second,” Dr. Jewitt observed.
“You can’t accurately trace that back to determine where you commenced your path.”
“This latest interstellar traveler represents a previously undetected group of objects, enriching the narrative that has gradually unfolded.”
“This achievement is now possible due to the powerful Sky Survey capability we previously lacked. We’ve reached a new milestone.”
Astronomers utilizing the Gemini North telescope at NSF’s International Gemini Observatory have observed the interstellar comet 3i/Atlas as it passes through our cosmic neighborhood.
This image from the Gemini North Telescope Multi-Object Spectrometer (GMOS-N) showcases the interstellar comet 3i/Atlas. Image credits: International Gemini Observatory/Noirlab/NSF/Aura/K. Meech, Ifa&U. Hawaii / Jen Miller & Mahdi Zamani, Noirlab.
Interstellar objects are those that emerge from and traverse beyond our solar system.
Ranging from several meters to a few kilometers in size, these cosmic fragments are remnants from the formation of the host star’s planetary system.
As they orbit their stars, interactions with the gravitational pull of nearby planets and stars can eject them into interstellar space, allowing them to traverse other solar systems.
Studying interstellar visitors provides critical insights into distant star systems.
They carry valuable information about chemical elements, including their formation timelines and locations, offering scientists glimpses into the formation of planetary systems throughout the history of the Milky Way galaxy.
3i/Atlas marks the third interstellar object discovered, following 1i/Oumuamua in 2017 and 2i/Borisov in 2019.
Astronomers suspect that numerous interstellar objects might regularly pass through our solar system, but capturing them is challenging as they are only visible when telescopes are oriented correctly at the right time.
Multiple teams worldwide utilize various telescopes to monitor 3i/Atlas during its brief visitation, enabling them to collectively assess its key properties.
While many aspects remain unknown, 3i/Atlas is already recognized as distinct in comparison to 1i/Oumuamua and 2i/Borisov.
Previous observations suggest that 3i/Atlas could have a diameter of up to 20 km (12 miles).
New comets typically exhibit highly eccentric orbits, which define how much the object’s path deviates from a perfect circle.
An eccentricity of 0 indicates a circular orbit, while 0.999 signifies a highly elongated ellipse.
Objects with an eccentricity greater than 1 follow paths that do not loop around the Sun and come from, then return to, interstellar space.
The eccentricity of 3i/Atlas is recorded at 6.2, classifying it as a highly hyperbolic interstellar object.
In contrast, “Oumuamua’s” eccentricity was around 1.2, and Borisov’s was about 3.6.
As of now, 3i/Atlas resides in Jupiter’s orbit, approximately 465 million km (290 million miles) from Earth and 600 million km (370 million miles) from the Sun.
On December 19, 2025, it will come within roughly 270 million km (170 million miles) of Earth, posing no threat to our planet.
The closest approach to the Sun will occur around October 30, 2025, at a distance of 210 million km (130 million miles).
During this close approach, it is expected to travel at about 25,000 km (15,500 miles) per hour.
The latest image of 3i/Atlas was obtained using the Gemini North Telescope Multi-Object Spectrometer (GMOS-N).
“The sensitivity and scheduling precision of the International Gemini Observatory played a critical role in observing this interstellar wanderer,” remarked Martin Still, NSF Program Director at the International Gemini Observatory.
“We eagerly anticipate the wealth of new data and insights as this object warms in sunlight before continuing its cold, dark journey through interstellar space.”
Research conducted by astronomer Matthew Hopkins and his team at Oxford University suggests that 3i/Atlas, the second interstellar comet discovered near our solar system, may have been on its trajectory over 3 billion years ago.
Top view of the Milky Way displaying the predicted orbits of our Sun and 3i/Atlas. Comets are represented by dashed red lines, while the sun is indicated by a dashed yellow line. The comet’s route to the outer thick disc is mostly clear, whereas the sun remains close to the nucleus of the galaxy. Image credit: M. Hopkins / Otautahi Oxford Team / ESA / Gaia / DPAC / Stefan Payne-Wardenaar / CC-SA 4.0.
“All comets formed alongside our solar system, like Halley’s comets, are up to 4.5 billion years old,” Dr. Hopkins explained.
“In contrast, interstellar visitors can be significantly older. Our statistical analyses indicate that 3i/Atlas is very likely to be the oldest comet we’ve observed thus far.”
Unlike 1i/Oumuamua and 2i/Borisov, the two previous interstellar objects that passed through our solar system, 3i/Atlas appears to be on a more inclined path through the Milky Way.
A recent study forecasts that 3i/Atlas is likely to be rich in water ice, as it probably formed around the star of the ancient, thick disc.
“This is an aspect of the galaxy that we’ve never encountered before,” said Chris Lintot, a professor at Oxford University and host of The Sky at Night.
“I believe there is a two-thirds chance that this comet predates the solar system and has been drifting through interstellar space ever since.”
As it nears the Sun, the heat from sunlight activates 3i/Atlas, generating a coma and tail composed of steam and dust.
Initial observations indicate that the comet is already active and may even be larger than any of its interstellar predecessors.
If this is validated, it could influence the detection of similar objects by future telescopes, such as the upcoming Vera C. Rubin Observatory.
Furthermore, it could offer insights into the role that ancient interstellar comets play in the formation of stars and planets throughout the galaxy.
“We’re in an exciting phase. 3i/Atlas is already displaying signs of activity,” remarked Dr. Michele Bannister, an astronomer at the University of Canterbury.
“The gases we might observe in the future, as 3i/Atlas is heated by the Sun, will help us evaluate our models.”
“Some of the world’s largest telescopes are currently monitoring this new interstellar entity. One of them may make a significant discovery!”
The astronomer utilizing ESO’s Extremely Large Telescope (VLT) has unveiled a new image of 3i/Atlas, marking it as the third interstellar object documented.
This VLT/FORS2 image, captured on July 3, 2025, depicts interstellar comet 3i/Atlas. Image credit: ESO/O. Hainaut.
3i/Atlas was identified a week ago by the NASA-supported Atlas Survey Telescope in Riojartad, Chile.
Commonly referred to as C/2025 N1 (ATLAS) and A11PL3Z, this comet is approaching from the direction of Sagittarius.
“In contrast to objects within the solar system, its highly eccentric hyperbolic orbit indicates its interstellar origin,” ESO astronomers stated.
Currently, 3i/Atlas is approximately 4.5 AU (670 million km, or 416 million miles) away from the Sun.
Interstellar objects pose no danger to Earth, maintaining a distance of at least 1.6 AU (240 million km, or 150 million miles).
Around October 30, 2025, it will make its closest approach to the Sun at a distance of 1.4 AU (210 million km, or 130 million miles).
“In the VLT time-lapse, you can observe 3i/Atlas moving to the right over approximately 13 minutes,” the astronomer remarked.
“These observations were gathered using FORS2 equipment at the VLT on the night of July 3, 2025, just two days post-discovery of the comet.”
“At the conclusion of the video, all frames are compiled into a single image.
“However, this record will not endure as the comet approaches Earth and becomes less visible.”
“As it currently traverses more than 600 million km from the Sun, 3i/Atlas is heading towards the inner solar system, expected to reach its closest approach to Earth in October 2025,” they noted.
“During that time, 3i/Atlas will be obscured by the Sun, but observations should resume in December 2025.
“Telescopes globally, including the VLT, will persist in monitoring this extraordinary celestial visitor to gather more insights into its structure, composition, and origin.”
3i/Atlas is only the third celestial object ever detected, following the interstellar asteroid 1i/Oumuamua in 2017 and the interstellar comet 2i/Borisov in 2019.
Images of 3i/Atlas captured by the Atlas telescope. Image credit: University of Hawaii.
The 3i/Atlas is currently about 670 million km (420 million miles) from the Sun and is expected to make its closest approach in October 2025, moving just within Mars’ orbit.
It is estimated to be up to 20 km (12 miles) in diameter, traveling at around 60 km (37 miles) per second relative to the Sun.
This comet poses no threat to Earth, remaining within a distance of 240 million km (150 million miles), which is more than 1.5 times the distance between the Earth and the Sun.
3i/Atlas is an active comet. As it approaches the Sun, the heat causes frozen gases to turn into vapor, releasing dust and ice particles into space and initiating the formation of a glowing coma and tail.
However, by the time it reaches its closest point to Earth, it will be obscured by the Sun. It is expected to be visible again by early December 2025, providing astronomers with an opportunity for further research.
“Finding possible interstellar objects is extremely rare, and it’s thrilling to see the Atlas telescope catch this asteroid,” said a representative.
“These interstellar visitors allow us to glimpse something intriguing from solar systems beyond our own.”
“3i/Atlas is the largest ever observed, yet numerous such objects traverse our inner solar system each year.”
“The likelihood of an impact with Earth is minimal, occurring less than once in 10 million years, but Atlas is consistently scanning the sky for potentially hazardous objects.”
Astronomers across Hawaii, Chile, and other nations are tracking the comet’s progression.
They seek to learn more about the composition and behavior of this interstellar visitor.
“It is precisely their foreign nature that makes interstellar objects like 3i/Atlas so remarkable,” an ESA astronomer stated.
“While all planets, moons, asteroids, comets, and life forms in our solar system share a common origin, our interstellar visitors are genuine outsiders.”
“They are remnants from other planetary systems, providing clues about the formation of worlds beyond our own.”
“It may take thousands of years before humans visit planets in another solar system, and interstellar comets give us the chance to stimulate our curiosity as we interact with something from another world.”
“These icy nomads offer a rare, tangible link to the broader galaxy. This material is fundamentally different from our own and is formed in unique environments.”
“Visiting such objects connects humanity with the universe on a grander scale.”
Comet 3i/Atlas is the third interstellar object detected in the solar system
E. Guido, M. Rocchetto, J. Ferguson
Interstellar objects have been observed speeding through the solar system, prompting both amateur and professional astronomers globally to direct their telescopes toward them, refining their orbital models to confirm their status as visitors from other stars.
The comet was initially designated A11PL3Z and marks the third documented interstellar object. The first, ‘Oumuamua, was identified in October 2017, shortly after its closest approach to Earth. Its bizarre acceleration sparked numerous theories, including the possibility that it might be an alien spacecraft. The second interstellar object, Comet Borisov, was discovered in 2019, allowing for more extensive observations early in its journey through the solar system.
The A11PL3Z was first detected by NASA’s Asteroid Terrestrial Impact Last Alert System (ATLAS). Earlier images of the object, once overlooked, were identified in data collected on June 14. New observations are underway in Chile and beyond through the Deep Random Survey. The Minor Planet Center—charged with the observation and reporting of such entities—has now officially named it 3I/ATLAS, acknowledging both its classification as the third interstellar object and the discoverers.
The object measures approximately 20 km wide and is estimated to move at around 60 km per second, gradually accelerating due to the sun’s gravitational pull. By October, it will reach its closest point to the Sun, passing within two astronomical units (twice the distance from Earth to the Sun) before swinging away and exiting our solar system.
The anticipated trajectory of 3i/Atlas marks its position as only the third interstellar object to be recorded in the solar system
CSS, D. Rankin
This creates a limited window for studying 3i/Atlas, although its visibility offers more time for observation compared to other interstellar entities. “They move through the solar system at astonishing speeds,” states Mark Norris from the University of Central Lancashire, UK. “It’s a race against time to learn as much as we can about them.”
Unfortunately, the technology needed to launch missions to intercept and investigate these celestial visitors remains out of reach, according to Norris. “Even if we started today, it would be too late,” he concludes. However, this may evolve soon, as the European Space Agency (ESA) aims to deploy a comet interceptor mission into space in 2029, where it will await encounters with newly discovered comets and interstellar bodies.
For now, astronomers must depend on existing telescopes to observe 3i/Atlas from a distance. “As we can track it until the end of the year, we have sufficient time to refine its trajectory, and there’s still time to focus the spectrometer on it,” mentions Richard Moisle. Our team is already eager to pinpoint the earliest possible observations. Everyone is highly enthusiastic and ready for what’s ahead.”
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Astronomers from the Atacama Large Millimeter/Submillimeter Array (Alma) have made observations of comet C/2014 UN271 (Bernardinelli-Bernstein).
Artist depiction of Comet C/2014 UN271. Image credits: NSF/AUI/NSF/NRAO/M.WEISS.
C/2014 UN271 was identified by astronomers Pedro Berner Dinnelli and Gary Bernstein through images captured in 2014 as part of dark energy research.
The comet spans approximately 140 km (85 miles) in diameter, making it over ten times larger than any known comet.
To date, little has been understood about the behavior of such cold, remote celestial bodies.
Recent findings from Alma revealed the intricate and dynamic jets of carbon monoxide gas erupting from the comet’s nucleus, offering the first direct evidence of what drives its activity in relation to the sun.
“With these measurements, we can understand how this massive, icy world functions,” stated Dr. Nathan Ross, an astronomer affiliated with a U.S. university and NASA’s Goddard Space Flight Center.
“We are observing explosive outgassing patterns that raise new inquiries about the comet’s evolution as it journeys deeper into the inner solar system.”
Alma observed C/2014 UN271 by detecting light from carbon monoxide gas in its atmosphere and thermal radiation when the comet was still distant from the sun.
Thanks to Alma’s exceptional sensitivity and resolution, scientists were able to focus on the very faint signals emitted from such cold and far-off objects.
Building on previous Alma observations that characterized the comet’s substantial nucleus size, the new findings measured the thermal signal to accurately assess the size of the comet and the dust surrounding its nucleus.
Their measurements for the nucleus size and dust mass are in line with earlier Alma observations, affirming it as the largest cloud comet ever identified.
Alma’s precision in measuring these signals enabled this research, providing a clearer understanding of this distant, icy giant.
“This discovery not only represents the first detection of molecular outgassing in a record-setting comet but also offers a rare glimpse into the chemical and dynamic processes of objects from the farthest reaches of the solar system,” the astronomer added.
“As C/2014 UN271 approaches the sun, we anticipate more frozen gases will start to evaporate, revealing further insights into the comet’s primitive composition and the early solar system.”
“Such discoveries help address fundamental questions about the origins of Earth and its waters, as well as the formation of life-supporting environments elsewhere.”
The team’s research paper was published in Astrophysics Journal Letters.
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Nathan X. Ross et al. 2025. Initial detection of molecular activity in the largest known OORT cloud comet: Alma Imaging of The Sun at C/2014 UN271 (Bernardinelli-Bernstein). apjl 986, L22; doi: 10.3847/2041-8213/add526
Halley’s Comet makes its appearance near Earth every 75 years. Nevertheless, the remnants of this comet give rise to two significant meteor showers annually: the Eta Aquarids.
During this meteor shower, the night sky lights up as Earth travels through the paths left by various famous comets, according to Shauna Edson of the Smithsonian National Air and Space Museum.
NASA’s Bill Cook describes the Eta Aquarids as “very fast meteors.”
On the peak night, which falls on Tuesday morning, we anticipate witnessing 10-15 meteors per hour under optimal viewing conditions, Cook noted.
However, with the moon approximately two-thirds full, visibility may be diminished.
The viewing period will extend until May 28th. For more information about the Eta Aquarids and other meteor showers, check out this meteor shower guide.
What is a Meteor Shower?
As Earth orbits the Sun, it encounters bits left behind by comets and sometimes asteroids several times a year. The Eta Aquarids originate from fragments of Halley’s Comet.
When these fast-moving space rocks enter Earth’s atmosphere, they experience friction with the air, causing them to heat up and eventually incinerate.
This process can create a brief glow in the surrounding air, leaving a luminous tail that marks the path of a “shooting star.”
You don’t need any special gear to view the meteor showers that light up the sky each year, just find a dark spot away from city lights.
How to View the Meteor Shower
The optimal time for observing meteor showers is early when the moon is positioned low in the sky.
The primary challenges to clear visibility are bright moonlight and artificial lights. A cloudless night with a faint moon provides the best conditions.
Remember to keep looking up. If you haven’t been distracted by your phone, your eyes will be well-adapted to spot a shooting star.
When Will the Next Meteor Shower Be?
The next major meteor shower, the South Delta Aquarids, will peak in late July.
Newly discovered Green Comet is being tracked by a telescope, which suggests it may break apart as it approaches the sun. Naked Eye Spectacle.
Comet Swan from the Oort Cloud Beyond Pluton has been visible through telescopes and binoculars in recent weeks, but experts suggest it may not have survived its most recent journey. Travel past the sun and is fading rapidly.
“We’ll soon be left with a dusty cleavage pile,” stated astrophysicist Carl Battamus in an email.
A newly discovered comet swan on April 6th.Mike Orathon via the AP
Comets are frozen balls of gas and dust from billions of years ago that frequently pass through the inner solar system.
“These are artifacts from when the solar system first formed,” explained Jason Ibarra, director of the West Virginia University Planetarium and Observatory.
The latest comet was spotted by amateur astronomers who used photos from cameras on a spacecraft operated by NASA and the European Space Agency to study the sun.
Unlike Tsuchinshan-Atlas, comets do not come close to Earth. Other notable flybys include Neowise in 2020, and from the 1990s, Halebop and Hi-Aku Take.
A newly discovered comet swan with a streaming tail on April 6th. Mike Orathon via the AP
The comet, also known as C/2025 F2, would have been visible just after sunset, slightly north of the sun. Its green color may be challenging to see with the naked eye.
This was the first journey past the sun for this object, making it particularly susceptible to disintegration, according to Batam. After the flyby, the remainder of the comet vanishes into the outer reaches of the solar system, believed to be its birthplace by scientists.
“I don’t know if it’s ever coming back,” noted Batam.
Despite conflicting with the results of some recent studies, this new discovery reinforces the claim that Jupiter-based comets like 67P/Churyumov-Gerasimenko may have contributed to providing water to Earth. This finding has been confirmed.
This pseudocolor four-image mosaic consists of images taken on February 3, 2015, from a distance of 28.7 km from the center of comet Churyumov-Gerasimenko. The size of the mosaic is 4.2 x 4.6 km. Image credit: ESA / Rosetta / NAVCAM / CC BY-SA IGO 3.0.
Water is crucial for the formation and sustenance of life on Earth, and continues to be central to life on Earth today.
It is believed that some water was present in the gas and dust that formed our planet around 4.6 billion years ago, but due to Earth forming close to the sun’s intense heat, a considerable amount of water is thought to have evaporated.
The process by which Earth became abundant in liquid water is still a subject of debate among scientists.
Studies have indicated that a portion of Earth’s water originates from steam released by volcanoes, which then condensed and fell into the oceans.
Furthermore, evidence suggests that a significant percentage of our oceans resulted from the impact of ice and minerals from asteroids and potentially comets hitting Earth.
A series of comets and asteroids colliding with inner solar system planets 4 billion years ago could have facilitated this occurrence.
While there is a strong theory linking asteroid water to Earth’s water, the role of comets has perplexed scientists.
Multiple measurements of Jupiter-based comets have indicated a strong correlation between their water and that of Earth.
This connection is based on a fundamental molecular signature utilized by scientists to track the origins of water across the solar system.
The deuterium (D) to ordinary hydrogen (H) ratio in an object’s water serves as this signature, providing insights into the object’s formation location.
By comparing this hydrogen ratio in comets and asteroids to that of Earth’s water, scientists can discern a potential connection.
Deuterium-rich water is more likely to form in cold environments, resulting in objects formed farther from the Sun, such as comets, exhibiting higher concentrations of this isotope compared to objects formed nearer to the Sun, like asteroids.
Measurements conducted over the past few decades on the deuterium in the water vapor of various other Jupiter-based comets have revealed levels akin to Earth’s water.
“It seems increasingly likely that these comets play a significant role in delivering water to Earth,” commented Dr. Kathleen Mandt, a planetary scientist at NASA Goddard Space Flight Center.
However, ESA’s Rosetta mission to 67P/Churyumov-Gerasimenko in 2014 challenged the notion that Jupiter-based comets aid in replenishing Earth’s water reservoirs.
Upon analyzing Rosetta’s water measurements, scientists discovered that it has the highest deuterium concentration among all comets, with approximately 100% more deuterium than Earth’s oceans (about 1 deuterium atom for every 6,420 hydrogen atoms), surpassing it by threefold.
“This was a significant revelation that compelled us to reassess everything,” remarked Dr. Mandt.
An advanced statistical computing approach was employed by the researchers to automate the laborious task of segregating deuterium-rich water from over 16,000 Rosetta measurements.
These measurements were taken within the gas and dust coma encircling 67P/Churyumov-Gerasimenko by Rosetta.
For the first time, Dr. Mandt and collaborators analyzed all water measurements from the European mission.
The researchers aimed to comprehend the physical processes influencing the fluctuations in hydrogen isotope ratios detected in comets.
Studies on comet dust in laboratory settings and observations indicated that comet dust could impact the hydrogen proportion detected in comet vapors, potentially altering how the comet’s water compares to Earth’s water.
“So, I was curious to see if I could find evidence of this phenomenon occurring in 67P/Churyumov-Gerasimenko,” added Dr. Mandt.
“This is one of those rare instances where a hypothesis is proposed and genuinely validated.”
In fact, scientists identified a distinct correlation between the deuterium measurements of 67P/Churyumov-Gerasimenko within its coma and the amount of surrounding dust near the Rosetta spacecraft, indicating that measurements taken in certain regions of the coma near 67P/Churyumov-Gerasimenko may not accurately represent the comet’s celestial composition.
As the comet traverses an orbit closer to the Sun, its surface warms, releasing gases from the surface, including dust particles with attached water ice fragments.
Research suggests that water containing deuterium has a higher tendency to adhere to dust particles compared to regular water.
When this ice on dust particles is expelled into a coma, it can create an illusion of the comet containing more deuterium than it actually does.
The researchers noted that by the time the dust reaches the outer regions of the coma, at least 120 miles away from the comet’s core, the coma depletes of water.
Once the deuterium-rich water dissipates, the spacecraft can precisely measure the amount of deuterium emanating from the comet’s core.
“This discovery holds profound implications not only for elucidating the role of comets in supplying water to Earth but also for comprehending comet observations that offer insights into the early solar system’s formation,” the researchers noted.
“This discovery provides a unique opportunity to revisit previous observations and prepare for future observations to better factor in the effects of dust.”
of study Published in a magazine scientific progress.
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Kathleen E. Mandt others. 2024. D/H of comet 67P/Churyumov-Gerasimenko almost on Earth. scientific progress 10(46);doi: 10.1126/sciadv.adp2191
456P/Panstars, an active main-belt asteroid first discovered in 2021, is repeatedly active, and its activity is linked to volatile ice formations, according to new observations from the Magellan-Baade and Lowell Discovery telescopes. It is likely that this is caused by sublimation.
456P/PanSTARS image taken on October 3, 2024 with the Magellan Baade Telescope in Chile and with the Lowell Discovery Telescope in Arizona on October 26, 2024. At the center of each image is the comet’s head or nucleus, the tail extends to the right. Image credits: Scott S. Sheppard / Carnegie Institution for Science / Audrey Thirouin, Lowell Observatory / Henry H. Hsieh, Planetary Science Institute.
“Main-belt comets are icy objects found in the asteroid belt between Mars and Jupiter, rather than outside the cold solar system, where icy objects would normally be expected,” said Henry Hsieh, senior scientist at the Planetary Science Institute.
“They have comet-like features, such as tails that extend away from the sun and fuzzy clouds as the sun’s heat evaporates the ice.”
These objects were first discovered in 2006 at the University of Hawaii by Dr. Hsieh and his then-doctoral supervisor, Professor David Jewitt.
“Main-belt comets belong to a larger group of Solar System objects known as active asteroids, which look like comets but have asteroid-like orbits in the warm inner Solar System,” the astronomers said.
“This large group includes not only objects that emit dust from evaporated ice, but also objects that have clouds or tails of ejected dust from collisions or rapid rotation.”
“Both main-belt comets and active asteroids in general are still relatively rare, but scientists are discovering them.”
456P/PANSTARRS was discovered as P/2021 L4 (PANSTARRS) through observations by Pan-STARRS1 on June 9 and 14, 2021, and observations by Canada, France, and Hawaii telescopes on June 14, 2021.
Dr. Hsieh and his co-authors observed the object twice in October 2024 using the Magellan-Baade Telescope and the Lowell Discovery Telescope, establishing its status as a main-belt comet.
“This object is not just an asteroid that experienced a one-off event, but is essentially an active icy object, like other comets in the outer solar system,” Hsieh said.
If 456P/PANSTARRS’s activity is due to something other than ice evaporation, its tail would be expected to appear only once, randomly, and not repeatedly as it approaches the Sun.
On the other hand, icy objects heat up every time they approach the sun, and the evaporated ice is carried away with the dust.
As the object moves away from the sun and cools, it ceases to be active.
Observations of repeated dust ejection activity during their approach to the Sun are currently considered the best and most reliable method of identifying main-belt comets.
“Confirmed main-belt comets are still largely unknown,” Dr. Xie said.
“We want to grow the population so we can understand more clearly what its broader characteristics are, such as its size, active period, and distribution within the asteroid belt. We will be able to better utilize them to track ice within the asteroid belt and across the solar system.”
of findings Published in American Astronomical Society Research Notes.
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Henry H. Shea others. 2024. Recurrence activity of main belt comet 456P/Panstars (P/2021 L4) confirmed. Resolution memo AAS 8,283;doi: 10.3847/2515-5172/ad90a6
This article is a reprint of a press release provided by the Planetary Science Institute.
A bright comet from the Oort cloud named C/2023 A3 (Tsuchinshan-ATLAS) is passing close to Earth and will be visible until late October 2024.
This image, taken by the ESA/NASA Solar-Heliospheric Observatory (SOHO) on October 10, 2024, shows Comet Atlas Gassan and its bright tail streaming from upper left to right. Mercury will be visible as a bright dot on the left. Image credit: ESA/NASA.
Comet Tsuchiyama-ATLAS It was discovered on January 9, 2023 by astronomers from China's Zishan Observatory.
The comet, also known as C/2023 A3, was independently discovered by South Africa's ATLAS on February 22, 2023.
It orbits the Sun in a retrograde orbit and lies at an inclination of 139°.
It reached perihelion on September 27, 2024, at a distance of 0.391 astronomical units. Its closest approach to Earth was on October 12th. It is expected to be 200 AU from the Sun in 2239.
Each day throughout October, the comet rises higher and higher in the western sky as it moves away from the sun. But as it progresses, it gets darker and darker.
October 14th to 24th is the best time to observe it using binoculars or a small telescope.
Eagle-eyed skywatchers may be able to spot the star with their naked eyes for a few days, but then binoculars or a telescope will be needed as it gets darker.
“Comet Tuchinshan-Atlas may have come from the Oort Cloud, a region of space between 2,000 times the distance between Earth and the Sun and one light year.” said Jason Ybarra, director of the WVU Planetarium and Observatory.
“This region is so far away that the gravitational pull from the Sun competes with the gravitational pull from passing stars and the entire Milky Way galaxy.”
NASA astronaut Matthew Dominick took this photo of comet Atlas Tsuchiyama on September 28, 2024. At the time, the comet was about 70.8 million kilometers (44 million miles) from Earth. Image credit: NASA/Matthew Dominick.
“The larger the orbit, the longer it takes for the comet to orbit that orbit,” he added.
“In the case of comets originating from the Oort cloud, their orbits take a very long time, so their orbits may change due to gravitational interactions with other bodies in the solar system, and it is possible to predict the future behavior of comets. It becomes difficult to do so.”
“If it gains enough energy from these interactions, Comet Gassan-ATLAS may never come back. It will have to wait at least another 80,000 years. In any case, it will be a once-in-a-lifetime event. It’s an event.”
Just before sunrise on September 28, NASA astronaut Matthew Dominick took a time-lapse photo of the comet Tuchingshan Atlas orbiting over the South Pacific Ocean southeast of New Zealand from the International Space Station.
From October 7th to October 11th, the comet brightly illuminated the field of view of the onboard LASCO (Large Angle Spectroscopic Coronagraph Experiment) instrument. ESA/NASA Solar Heliosphere Observatory (Soho).
This device uses a disc to block the sun's bright light, making it easier to see details and objects near the sun.
On March 25, 2024, Dr. Hanjie Tan, a PhD student in astronomy in Prague, Czech Republic, discovered a comet in a photo. ESA/NASA Solar Heliosphere Observatory (SOHO) spacecraft confirmed to be the 5,000th comet discovered using SOHO data. Even though this observatory was not designed as a comet hunter, it took him 28 years in space to accomplish this milestone.
SOHO-5000, the 5,000th comet discovered by the SOHO spacecraft, is indicated by a small white box in the upper left part of this image. The enlarged inset shows the comet as a faint dot between vertical white lines. This image was taken by SOHO’s Large Angle Spectroscopic Coronagraph (LASCO) on March 25, 2024. Image credit: NASA/ESA/SOHO.
SOHO, a joint ESA and NASA mission, was launched in December 1995 to study the dynamics of the Sun and its outer atmosphere, called the corona.
spaceship Large angle spectroscopic coronagraph‘s instrument uses an artificial disk to block the sun’s bright light, allowing scientists to study the sun’s immediate corona and environment.
This will allow SOHO to do something that many other spacecraft cannot: see comets flying close to the Sun, known as sun-grazing comets or sungrazers.
Many of these comets only become bright when they are too close to the Sun to be seen by other observatories, otherwise they would go undetected and get lost in the bright glare of our star.
Astronomers had hoped that SOHO would discover a comet by chance during its mission, but the spacecraft’s comet-finding capabilities made it the most prolific comet detector in history, making it the most prolific comet detector known today. We have discovered more than half of the comets.
In fact, soon after the spacecraft launched, people around the world started spotting so many comets in images that mission scientists needed a way to track them all.
In the early 2000s, we launched the NASA-funded Sungrazer project to allow anyone to report comets they saw in SOHO images.
“When LASCO was launched, no one imagined that it would become the most prolific discoverer in history,” said Dr. Carl Battams, a research scientist at the U.S. Naval Research Laboratory who is the principal investigator for LASCO and the Sungraser program. Ta.
“The amount of data and science that has been returned is simply beyond our imagination.”
The 5,000th discovery was made by Hanjie Tang, an amateur astronomer from Guangzhou, China. He is currently completing his PhD in astronomy. Student in Prague, Czech Republic.
Tan has been part of the Sungrazer project since he was 13 years old and is one of the project’s youngest comet discoverers.
He discovered comet SOHO-5000 in images from LASCO’s C2 camera.
Unlike most SOHO comets, this one very likely survived the Sun’s passage.
It will pass approximately 8.2 million km (5.1 million miles) from the Sun. This is slightly farther from the Sun than the current orbit of NASA’s Parker Solar Probe.
“Since 2009, we have discovered more than 200 comets,” Tan said.
“I joined the Sungrazer Project because I love looking for comets.”
“It’s really exciting to be the first to see a comet that has been traveling through space for thousands of years brighten so close to the sun.”
SOHO-5000 is a small, short-period comet that belongs to the Marsden family of comets, named after Dr. Brian Marsden, who first recognized the group.
The Marsden Group was unknown until SOHO/LASCO discovered it.
Of SOHO’s 5,000 comets, only about 75 belong to this group.
“Looking at the statistics of 5,000 comets and their orbits and trajectories through space is a very unique data set and really valuable science,” Dr. Battams said.
“This is a testament to the countless hours project participants have put into this.”
“We simply could not have reached this milestone without the work of our project volunteers.”
The Devil’s Comet, known for its occasional explosions, is currently visible in the night sky, and fortunate observers may catch a glimpse of it during the eagerly awaited solar eclipse next month.
Comet 12P/Ponsbrooks earned the nickname “Devil’s Comet” after an eruption last year left behind two distinctive trails of gas and ice resembling devil’s horns.
From the Northern Hemisphere, the comet is currently visible with binoculars or telescopes. As it moves through the inner solar system and approaches its closest point to the sun in mid-April, it may become visible to the naked eye by the end of the month.
Comets typically consist of a core of dust, gas, and ice surrounded by a bright gas cloud called a coma. These objects are remnants from the formation of the solar system and can be several miles wide, according to NASA.
The core of a comet can heat up due to sunlight and solar radiation, sometimes leading to explosive events, as seen with Comet 12P/Ponsbrooks. Observers in the Northern Hemisphere can currently see the comet in the western-northwestern sky in the evening.
The comet is expected to brighten towards the end of the month and, under clear and dark conditions, may remain visible until early May. If the comet experiences significant flares in the coming weeks, it could be visible during the total solar eclipse on April 8 along the path stretching from northeast Texas to Maine.
Despite uncertainties surrounding rare synchronistic events, there is a good chance of spotting the comet on its own in the evening sky. Comet 12P/Pons-Brookes was first discovered in 1812 by French astronomer Jean-Louis Pons and later observed in 1883 by British-American astronomer William Brooks. Due to its 71-year orbit around the sun, sightings of this comet are infrequent.
Currently in orbit within the inner regions of the solar system is comet 12P/Pons-Brooks, also known as Pons-Brooks, which is making its first appearance in over 70 years and is expected to be visible without the aid of telescopes soon. This massive ice chunk, roughly 30 kilometers (19 miles) in diameter, is comparable in size to Mount Everest and is considered one of the brightest known periodic comets by astrophysicists. Pons-Brooks, classified as a Halley-type comet, has an orbit around the Sun of 71.3 years and was last observed in the sky in 1954. Discovered in 1812 by Jean-Louis Pons and later confirmed in 1883 by William Robert Brooks, this is the first recorded sighting of the comet dating back to 1385.
When is Comet 12P/Pons-Brooks Visible?
Comet 12P/Pons-Brooks is currently visible and will remain so until April 21, 2024, with optimal viewing conditions expected towards the end of March. With binoculars or a small telescope, the comet is already observable in the sky, particularly when the Moon is located in the west below the Andromeda Galaxy moving through Pisces. By the end of the month, the comet will pass near the brighter stars in Aries, moving in the direction of Jupiter. As its brightness increases towards the end of the month, it may become visible to the naked eye under clear, dark skies. On March 31st, Pons-Brooks will be just 0.5 degrees away from a bright star named Hamal, which is equivalent to the diameter of the full moon, according to Strom. Those having trouble locating these constellations can benefit from downloading a stargazing app. For residents of the United States, the comet may also be visible in the sky during the total solar eclipse on April 8, 2024. Following its closest approach to the Sun on April 21, Pons-Brooks will fade and become visible only to observers in the southern hemisphere.
Why the Name “Devil’s” Comet?
The recent sighting of Pons-Brooks is not its first appearance in recent times. Referred to as the “Devil’s Comet,” due to a peculiar outburst in July 2023 that led to a temporary brightening resembling devil horns, Pons-Brooks is classified as a cryovolcanic comet that sporadically erupts, expelling dust, gas, and ice into space. These eruptions are triggered by the comet warming up as it nears the Sun, resulting in increased pressure causing the release of icy material from beneath the surface of the comet. The gas forms a bright coma, a halo of evaporated material surrounding the solid core of the comet. Comets appear brightest when closest to the Sun due to sunlight reflecting off the evaporated material, with the tails formed by interaction with charged particles from the solar wind. Pons-Brooks experienced similar but less intense outbursts on various dates in recent months, contributing to its brightness when close to the Sun.
What Does “12P” Mean?
The designation “12P” in the comet’s name indicates that it is the 12th comet discovered within a set period. Baskill explains that long-period comets, originating from the edge of the solar system, may have orbits lasting thousands or even tens of thousands of years, while short-period comets like Pons-Brooks return to the inner solar system in less than 200 years. Notable short-period comets include Comet Halley, with a period close to that of Pons-Brooks, expected to return in 2061. Current estimations suggest there are around 3,910 known comets in total, but astronomers believe there could be up to 1 trillion comets within our solar system.
Upcoming Comets
Expect to observe Comet 13P/Olbers in June and July, with observers in the Northern Hemisphere likely to spot it using binoculars. This comet, also known as a Halley’s Comet, orbits the Sun every 69 years. In late 2024, Comet C/2023 A3 is predicted to enter the inner solar system, potentially showcasing exceptional brightness in September and October, comparable to the brightest stars and potentially earning the title of “Great Comet.”
About Our Experts:
Dr. Paul Strom serves as an Assistant Professor within the Astronomy and Astrophysics Group at the University of Warwick, focusing on the PLATO space mission and various astrophysical topics, particularly far-ultraviolet observations to understand the environments where young planets form. His research paper titled “Exo-solar Comets from a Solar System Perspective” was published in the journal Publications of the Astronomical Society of the Pacific.
Dr. Darren Baskill is an outreach officer and lecturer at the University of Sussex’s School of Physics and Astronomy. Previously involved with the Royal Observatory Greenwich, he organized the annual Astronomical Photographer of the Year competition.
Comet 12P/Ponsbrooks observed near Tromsø, Norway on March 5th
Bernt Olsen
One of the brightest known comets is headed toward Earth and could be visible to the naked eye within the next few weeks. Follow our guide and find Comet 12P/Pons-Brooks for yourself.
When will the comet be visible?
Comet 12P/Pons-Brooks orbits the sun for 71 years, during which it travels to the outer reaches of the solar system and back again. At this time, on April 21st, it will reach its perihelion, which means it will be closest to the sun. The comet will continue to approach Earth, reaching its closest approach on June 2nd at a distance of 232 million kilometers.
When is the best time to look for comets?
Although it will be close to Earth in June, the best time to see the comet in the Northern Hemisphere will be over the next few weeks, as the evenings will become brighter and less visible after the end of April. By June, it will be visible only in the Southern Hemisphere.
Where in the sky will comets appear?
12P/Pons Brooks has moved from the constellation Andromeda through the night sky to the constellation Pisces, where it is now located directly below the bright star Miraak. It will move into Aries at the end of March. It is expected to reach magnitude 5 and should be visible with the naked eye or with binoculars from areas with dark skies.
How can I see comets?
It’s best to plan ahead. Use astronomical observation software Stellarium etc. Pinpoint exactly where the comet will be visible on the days and times you want to see it. In the Northern Hemisphere, the comet will be near the horizon just after sunset and will set earlier as March progresses. At the end of the month, the sun sets a few hours after sunset, so we recommend viewing it as soon as it gets dark.
What do comets look like?
The core of 12P/Ponsbrooks is about 30 kilometers in diameter and, like other comets, appears to have a bright center and a tail behind it. Sightings of this particular comet date back to at least 1385, when Chinese and European astronomers recorded sightings of this comet.
Can I see Comet 12P/Ponsbrooks during a solar eclipse?
If you’re lucky enough to be in the path of the total solar eclipse on April 8, you might be able to spot the comet between the Sun and Jupiter. Jupiter appears to the upper left of the Sun during that period. The moon blocks all sunlight for four minutes.
In March 2024, early risers should be able to view comet C/2021 S3 (PanSTARRS) through binoculars as it approaches Earth.
Comets, often referred to as “dirty snowballs,” are icy objects that travel through space, leaving behind a trail of dust and gas as they approach the Sun.
C/2021 S3 was discovered in September 2021 by one of the PanSTARS telescopes on Mount Haleakala (Hawaii) and is predicted to reach a magnitude between 7 and 9 (the lower the magnitude, the more powerful the comet is). (looks bright).
You can’t see it with the naked eye, but you should be able to spot it with a decent pair of binoculars. However, predicting a comet’s final brightness is somewhat difficult. Comets are difficult to handle and prefer to act independently.
But don’t worry, Comet C/2021 S3 poses no danger to Earth and will pass us safely.
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When can we see Comet Panstars tonight?
A comet is approaching Earth on March 14, 2024. It reached perihelion, the closest point to the Sun in its orbit, on Wednesday, February 14, 2024, when it became visible from the United States and the United Kingdom.
During the second half of the month, around March 18th to March 29th, the Moon begins to interfere as it approaches the full moon on March 25th. Starting on the opposite side of the sky, the moon gradually approaches the comet towards the end of the month.
In late March, especially if you want to spot the comet passing through the Coat Hanger star map (more on how to find the Coat Hanger below), look up around 3 a.m. GMT. Basically, as soon as the comet is above the horizon. As dawn approaches, an interfering moon will spoil the progress.
How to see a comet
Comet C/2021 S3 is heading northeast, passing roughly between the large constellation of Ophiuchus above and the small constellations Scutum and Aquila below. Ophiuchus and Aquila both straddle the celestial equator, while Scutum lies just south of it.
Until about March 18, look to the southeast early in the morning as the sky begins to lighten. By this point, the comet is visible above the horizon and the Moon appears relatively out of the way.
The best time to see the views is around 3am in late March. Also, at this time, Comet C/2021 S3 will pass over the Coathanger Cluster, a small star group. And yes, it’s exactly like the name! Here’s how to find it:
Find the Summer Triangle. Let’s start by identifying the Summer Triangle. This is an easily recognizable asterism, formed by the bright stars Deneb in Cygnus, Vega in Lyra, and Altair in Aquila.
Find the constellation Little Vulgar. Once you find the Summer Triangle, look for the constellation Little Bitis. It is located between Cygnus and Sagittarius and is shaped like an extended M. It can be found by drawing an imaginary line north from the star Altair in the Summer Triangle.
Move to coat hanger. Once you find Vulpecula, look for the Coathanger Asterism. This is very distinctive and looks like a coat hanger or an upside down question mark. The Coathanger is an asterism within Vulpecula and is easy to find once you enter the right area.
If you’re star hopping and having trouble finding the star on your coat hanger, downloading a stargazing app can help. Here are all the best astronomy apps.
Here’s what you can do to help astronomers discover moreComet
Photos from amateur astronomers help researchers improve space weather predictions and influence solar wind technology.
Comet tails, also known as “cosmic windsocks,” can tell us a lot about the strength and direction of the solar wind. For example, if the tail peels off or wobbles, you can infer that there is increased activity.
Please send images, including date, time and location, to researcher Sarah Watson at srwatson@pgr.reading.ac.uk. The research team is particularly interested in observing the broken tail.
The comet is not expected to be bright enough to be seen with the naked eye, so if you want to photograph it you’ll need a small telescope or a camera with a large lens.
Why do comets get brighter when they get closer to the sun?
Comets become more active as they get closer to the sun. Intense heat from the sun and solar radiation can evaporate ice cores and suddenly release dust and gas. This process forms a glowing coma (a cloud of gas and dust) around the nucleus and a bright tail that reflects sunlight.
This tail can span millions of kilometers and is influenced by a combination of different processes. For example, the solar wind, which is made up of charged particles, can interact with these gases to produce ion tails that point away from the sun.
In addition, the sun’s radiation pressure develops and displaces the dust particles. This can lead to the formation of a separate dust tail, which often lags behind the ion tail. A combination of sublimation (the transformation of solid ice directly into gas), ionization, and radiation pressure all affect the appearance of comet tails as they orbit the Sun.
And the closer the comet is to the Sun, the more intense this activity becomes, and the brighter it appears in the night sky.
the current, 3,922 known comets (and its fragments) of our solar system.
But it can also get dark…
However, this is not always the case. When a comet runs out of volatile matter, it may lose its ability to produce a bright coma and tail. Therefore, comets appear darker as they get closer to the Sun. In addition, comets can develop a crust that makes it completely impossible for material to escape.
Scientists hypothesize that comet C/2021 S3 may already have a mineral crust forming on its surface. If this were the case, the comet’s albedo (reflectance) would be much lower because the crust would protect its volatile-rich interior from the sun. In other words, it won’t be as bright as other comets this year. But if the underlying material continues to evaporate and creates enough pressure to break through the Earth’s crust, a flare can occur. That would be fun.
When is the next comet?
Comet C/2021 S3 is one of the few bright comets we’re watching this year. Next up is Comet 12P/Pons-Brooks, also known as the “Devil’s Comet” thanks to its distinctive “horns” that began to widen towards the end of 2023.
It can be easily seen with a telescope or binoculars, and will begin to brighten towards the end of March 2024, so it could be the first comet of 2024 to be visible to the naked eye.
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