Tag Archives: comets

Two Greenish Comets Illuminate the Night Sky This Month.

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This autumn, two greenish comets are traversing the inner solar system, presenting a unique opportunity to view them in the coming weeks.

The comets, designated C/2025 A6 (Lemon) and C/2025 R2 (SWAN), are currently observable from the Northern Hemisphere as they journey through our cosmic vicinity.

It is quite uncommon for a comet to be visible twice within the same month.

Both comets can be observed with binoculars or small telescopes until the end of October. Comet Lemon may become visible to the naked eye around its closest approach to Earth and peak brightness on or about October 21st.

Several astronomy enthusiasts have already spotted this icy traveler.

Astrophotographer Julian de Winter, a junior lecturer at the University of Mons in Belgium, captured Comet Lemon’s striking emerald glow and elongated tail from Texas in late September.

The faint green hue arises from carbon in the gas cloud enveloping the comet’s nucleus.

In the Northern Hemisphere, Comet Lemon will appear near the Big Dipper before dawn from now until mid-month. According to EarthSky, a site focused on astronomy and skywatching, the best viewing time is in the northeast sky, just beneath the distinctive bowl and handle of the Big Dipper.

In about a week, the comet will rise in the western sky and can be seen in the evening sky. From then until the month’s end, visibility of these celestial objects may be challenging, although they might be seen with the naked eye.

Comet Swan is visible in the evening sky until the end of the month. The prime time to locate it is about 90 minutes post-sunset, directed towards the southwest. This comet may not be bright enough for naked-eye observation, so binoculars or a small telescope will be necessary.

In the coming days, Comet Swan will ascend higher in the horizon post-sunset and could brighten as it nears its closest approach to Earth around October 20th.

Under optimal conditions of clear, dark skies with minimal light pollution, it may even be possible to see both comets on the same night towards the month’s end.

Discovered in January by the Lemmon Mission, Comet Lemmon tracks near-Earth objects using telescopes located in Arizona’s Santa Catalina Mountains.

Comet SWAN was identified more recently by amateur astronomers in early September while examining images from NASA’s Solar and Heliospheric Observatory’s SWAN instrument, which has been studying the Sun since its launch in 1995.

Additionally, this month, another type of comet—one originating from outside our solar system—is passing through. Comet 3I/ATLAS, the third identified interstellar visitor, was recently photographed by a spacecraft orbiting Mars and is set to make its closest approach to the Sun around October 30th.

Source: www.nbcnews.com

Interstellar Comets Become Only the Third Known Visitors Beyond Our Solar System

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Astronomers are laying out welcome mats for newly discovered visitors making their way through our solar system.

This particular object is categorized as a comet and marks only the third confirmed interstellar visitor in recorded history to traverse our cosmic neighborhood.

The comet, named 3i/Atlas, poses no threat to Earth, maintaining a distance of about 150 million miles while it accelerates. As reported by NASA.

This interstellar comet was initially discovered on Tuesday by The final alert system for the asteroid’s terrestrial impact (Atlas) located in Rio Hartado, Chile. The research telescope, funded by NASA, is actually two telescopes from Hawaii and one in Chile, in addition to a fourth in South Africa, all dedicated to scanning the sky multiple times nightly for asteroids that could threaten Earth.

Researchers examined archived data from three different Atlas telescopes and Zwick temporary facilities at the Palomar Observatory in California, uncovering observations that would corroborate the findings. Other telescopes worldwide have also joined the initiative, as stated by NASA.

“ESA’s planetary defenders are currently monitoring an object provisionally known as #A11PL3Z, utilizing telescopes from around the globe,” the European Space Agency announced in a post on X this Wednesday.

Interstellar Comet 3i/Atlas.
David Rankin/Saguaro Observatory

The comet is located around 420 million miles away and is rapidly traveling from the direction of the constellation Sagittarius. NASA commented in a blog post regarding the findings. Sagittarius is a prominent constellation in the Southern Hemisphere and indicates the center of the Milky Way galaxy.

The agency noted that 3i/Atlas will make its closest approach to the sun around October 30th, passing roughly 130 million miles away, close to Mars’ orbit.

NASA indicated that the comet will remain observable from ground-based observatories until September, providing scientists with the opportunity to gather additional details about these cosmic visitors, including their size. After September, 3i/Atlas will be too close to the sun for telescopes to observe, but it is expected to become visible again in early December, as it reemerges on the far side of the sun.

The upcoming months will present a rare chance to study these celestial tourists traveling through the solar system. The first confirmed interstellar object, observed in 2017 by the University of Hawaii’s Pan-Starrs1 telescope, was the rocky body named “Oumuamua” (Hawaiian for first visitor), notable for its reddish hue and elongated cigar-like shape. As noted by NASA.

The only other known interstellar visitor is 2i/Borisov, a comet discovered in 2019 by amateur astronomer Gennady Borisov.

Source: www.nbcnews.com

Twice as many dark comets discovered in new study

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dark comet First Interstellar Object 1I/2017 U1 ‘A small object with no detected coma, similar to ‘Oumuamua, with large accelerations that can be explained by volatile outgassing. These objects represent a potentially widespread class of small objects that lie further in the continuum between asteroids and comets and whose active nature is inferred from their orbital motions. Michigan State University astronomer Darryl Seligman and his colleagues have now detected seven new dark comets, proving that there are two distinct populations of these objects.

This artist’s impression shows ‘Oumuamua, the first interstellar object discovered in the solar system. Recent observations show that the object is moving faster than predicted as it leaves the solar system. Astronomers speculate that the ejection of material from the surface due to solar heating is responsible for this behavior. This release of gas can be seen, in this artist’s impression, as a subtle cloud emitted from the side of the object facing the sun. Image credits: NASA / ESA / Hubble / ESO / M. Kohnmesser.

In 2003, astronomers noticed that asteroid 2003 RM’s orbit deviated slightly from its expected orbit. This motion cannot be explained by the acceleration typical of asteroids.

Then, in 2017, the interstellar object ‘Oumuamua passed through our solar system, leaving astronomers perplexed.

Like a typical asteroid or comet, it was moved in part by the gravity of other bodies in the solar system, such as the sun.

But astronomers also discovered that ‘Oumuamua is accelerating beyond that, likely due to the release of previously trapped gas.

The strength of the thrust added by such outgassing defied that of a typical asteroid and rivaled the speed of a comet.

problem? ‘Oumuamua lacked the bright dust tail that is characteristic of comets, so it could not be easily classified as an asteroid or comet.

In 2023, astronomers identified seven objects in our solar system that reflect the same unusual features as ‘Oumuamua.

These objects were classified into an entirely new class of objects: the first seven dark comets.

“One of the most important reasons we study small objects like asteroids and comets is because they tell us about how matter is transported around the solar system,” Seligman said. the doctor said.

“Dark comets are a new type of near-Earth object that may contain water, and could provide a new source of materials needed for the development of life to Earth.”

“The more we learn about them, the more we will understand their role in the origin of the Earth.”

Dr. Seligman and his co-authors not only discovered seven new dark comets, but also compared the total number of known comets and identified two different types.

The first type is called an outer dark comet. These are large objects with eccentric orbits similar to Jovian comets and may have originated outside the solar system.

The second type is called an internal dark comet. These are small celestial bodies with roughly circular orbits that move through the inner solar system close to Earth and may have originated in the asteroid belt.

“What’s interesting about these objects is that although they look like asteroids, their motion is similar to that of comets,” said Dr. David Farnochia, a navigation engineer at NASA’s Jet Propulsion Laboratory.

“This is a puzzle that challenges the way we have always classified objects as either asteroids or comets.”

Dr. Seligman said, “Expanding our knowledge of dark comets will help us understand the context in which ‘Oumuamua was a fortuitous event that has left the solar system and is no longer observable.”

“What many people might not normally think about is that the solar system is a chaotic place.”

“We don’t know where things came from, but with 14 currently known dark comets orbiting within our solar system, we will collect more data in the coming years and hopefully uncover answers. Opportunities are opening up: the formation of our own planet.”

This finding is reported in the following article: paper in Proceedings of the National Academy of Sciences.

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Darryl Z. Seligman others. 2024. Two distinct populations of dark comets, distinguished by orbit and size. PNAS 121 (51): e2406424121;doi: 10.1073/pnas.2406424121

Source: www.sci.news

Comets are the most likely carriers of life’s essential building blocks to planets in clusters

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Nearby neighboring worlds can slow down the comet enough to allow the building blocks of life to survive

Shutterstock/Bradaki

It may be easiest to deliver materials for life to neighboring planets. Comets can carry many of the key building blocks of life, such as amino acids and other organic compounds, but their ability to deliver those building blocks to a particular planet depends on the configuration of their broader systems. It may depend.

There are several ideas about how the ingredients for life began on Earth, but the common idea is that a comet hit the Earth and organic molecules were deposited here. But comets tend to travel through space at extremely high speeds, and if they hit a planet at more than about 20 kilometers per second, the chances of their important compounds surviving the impact are almost zero.

Richard Anslow Researchers at the University of Cambridge ran a series of simulations to investigate how planetary systems can slow down comets and reduce their impact velocity enough to preserve these compounds. In ideal conditions, a slow impact would leave behind a type of prebiotic soup called a comet pond within the impact crater.

They discovered that there are two types of systems that can slow down a comet by 5 to 10 kilometers per second. One is a system with relatively massive stars, where everything tends to orbit slightly. For planets that are slow and have several planets spaced closely together like peas in a pod, the comet could weave between them and lose speed over time. there is.

“The best planetary systems are on relatively low-mass planets like Earth, around high-mass stars similar to the Sun but perhaps even more massive, and close enough for other rocky planets to pass through.” “It would be in a planetary system that has comets around it,” Anslow said.

He said that if astronomers eventually detect signs of life on other planets, simply examining the overall system configuration could help them understand how it got there. and that it could advance our limited understanding of how life formed. Earth.

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Source: www.newscientist.com