Spectroscopy enables astronomers to detect traces of matter in stars, galaxies, and other cosmic entities. Black holes consume dust and encounter various phenomena around them; as material spirals into a black hole, it compresses and heats up. Stephen Finkelstein, a co-author and professor of astronomy at the University of Texas at Austin, noted that all of this can be observed through spectroscopy.
“We’re searching for these signatures of extremely fast gas,” Finkelstein explained. “We’re discussing speeds of 1,000, 2,000, and at times even 3,000 kilometers per second. There’s nothing else in the universe that moves this quickly, so we can confirm it must be the gas surrounding a black hole.”
Scientists have pinpointed a potential distant black hole candidate, which stands as the oldest candidate confirmed via spectroscopy, he added.
Researchers also find galaxies containing new black holes to be intriguing discoveries. According to Taylor, these galaxies belong to a class known as “Little Red Dots.”
While not much information is available about Little Red Dots, they were first detected by the James Webb Space Telescope. Some have been found relatively close by, but Finkelstein indicated that they are likely more prevalent in the early universe.
Investigating the Capers-Lrd-Z9 Galaxy may offer insights into the rarity of red dots and what defines their unique coloration, researchers noted. It could also shed light on the growth of these ancient black holes during the universe’s formative stages.
In subsequent studies, researchers aim to locate more black holes in the distant cosmos.
“We’re just going to examine a very limited section of the sky using the James Webb Space Telescope,” Finkelstein stated. “If we discover one thing, there ought to be more.”
The sun serves as a fundamental source of heat and light in the solar system, with its energy generated in the core through the collision of hydrogen ions and helium.Nuclear Fusion. Consequently, while the surface temperature of the sun is extremely hot by Earth’s standards—approximately 10,000°F or 5,600°C—it is relatively cooler compared to the center, which reaches around 27,000,000°F or 15,000,000°C.
Heat and light travel from the sun’s center to its surface via two main processes: one is similar to how the sun heats the Earth, known as radiation. Here, energy moves outward through light particles, or photons. Conversely, heat transfer occurs on Earth through the process of convection, with cold gas descending while warm gas rises. This creates a swirling motion within the sun, where hot gases near the core move upward and cooler gases sink back down.
A diagram of the sun illustrating how convection and radiation influence heat movement at different depths. “Sun poster” by Kelvinsong is licensed under CC by-sa 3.0.
The interplay of radiation, convection, and the sun’s varying rotational speeds based on distance from the equator results in uneven heating of the solar surface, leading to both hot and cold areas. While scientists have a grasp of this general pattern, discrepancies exist between models predicting solar surface temperatures and observed data. The model estimates a temperature of around 2,000 Kelvin (k), translating to approximately 3,100°F or 1,700°C for the coldest sections, yet actual findings indicate these regions are around 4,000k, or about 6,700°F or 3,700°C.
This paradox highlights the challenges in understanding heat transfer within the sun. Several unknown factors may lead to the observed discrepancy of over 1,000k in the coldest spots. A team of researchers investigated one possible explanation for the missing heat by conducting both two-dimensional and three-dimensional simulations. They hypothesized that when convection separates neutral charged gases from the sun’s center, negatively charged electrons are driven by a magnetic field near the sun’s surface, generating additional heat. This phenomenon is referred to as Thermal Farley-Bnemann’s instability, or TFBI Turbulence.
The team employed two computer programs, ebysus and Epic, to simulate these cold bubbles in the outer layer of the sun, known as the Chrome area, over a span of 8-10 milliseconds. They incorporated variables such as material density, magnetic field strength, and collision frequency into their simulations. The TFBI turbulence was then integrated into the 2D ebysus model, which was compared with heating observed in the EPPIC simulations in both 2D and 3D.
The primary distinction between the programs lies in how they treat gas: ebysus models it as a swirling liquid, facilitating easier movement calculations, while Epic views it as a collection of bouncing particles that generate electromagnetic fields, complicating calculations. They conducted five simulations: one in 2D with EBYSUS, which was the fastest yet potentially the least accurate, one in 2D with Epic, which was slower but arguably more realistic, and two in 3D with EPPIC, which, while the slowest, yielded the most accurate outcomes.
The results from their 2D simulations indicated that turbulent heating could increase temperatures in cold regions by over 700,000. Similar findings were observed in the 3D simulations as well. The team contended that their simulations demonstrated how turbulence from the TFBI could augment heat in the sun’s cooler areas beyond what convection and radiation contribute. Nonetheless, they recommended that future research extend over longer time frames to fully grasp the implications of these processes. Additionally, comparisons between 2D and 3D simulations suggest that scientists can effectively investigate this phenomenon using quicker 2D fluid models, achieving results comparable to more complex and resource-intensive 3D particle models.
All previously observed images were captured from the Sun’s equatorial region. This is due to the fact that Earth, along with other planets and operational spacecraft, orbits the Sun in a flat disk known as the zodiac plane. By adjusting its orbit away from this plane, the ESA Solar Orbiter spacecraft unveils the Sun from an entirely new perspective.
A lower-half image of the Sun, highlighting a square area around its Antarctic. Captured in ultraviolet rays, it reveals hot gases in the Sun’s corona, glowing yellow as they extend outwards with threads and loops. Image credits: ESA/NASA/SOLAR ORBITER/EUI Team/D. Berghmans, Rob.
Professor Carol Mandel, ESA’s Director of Science, remarked:
“The Sun, being our closest star, is essential for life but can also disrupt modern power systems in space and on Earth. Therefore, understanding its mechanisms and predicting its behavior is crucial.”
“The new and unique perspectives provided by the Solar Orbiter mission signal the beginning of a new era in solar science.”
The images were captured by three different scientific instruments on the Solar Orbiter: Polarimetry and Helioseismology Imager (PHI), Extreme Ultraviolet Imager (EUI), and Spectral Imaging of the Coronal Environment (SPICE).
“Initially, I was uncertain of what to anticipate from these observations. The solar pole is truly a Terra Incognita,” said Professor Sami Solanki, leader of the PHI team at the Max Planck Institute for Solar System Research.
This collage shows the Antarctic of the Sun captured on March 16-17, 2025, as the solar orbiter observed from a 15° angle relative to the solar equator. This marked the first high-angle observation campaign just days before achieving its current maximum viewing angle of 17°. Image credits: ESA/NASA/Solar Orbiter/PHI/EUI/SPICE Team.
Each instrument on the Solar Orbiter observes the Sun differently.
PHI captures images of the Sun in visible light (top left) and maps its surface magnetic field (top center).
EUI images the Sun in ultraviolet light (top right), unveiling the corona, a multi-million-degree gas layer in the Sun’s outer atmosphere.
SPICE captures light from various temperatures of charged gases at the Sun’s surface, thereby revealing different layers of its atmosphere.
By analyzing and comparing observations from these three imaging instruments, we can understand how materials in the Sun’s outer layer move.
This could uncover unexpected patterns like polar vortices (swirling gases), reminiscent of those found around the poles of Venus and Saturn.
These innovative observations are crucial for understanding the solar magnetic field, particularly why it inverts every 11 years, aligning with peaks in solar activity.
Current predictive models for the 11-year solar cycle struggle to accurately forecast when and how the Sun will reach its peak activity.
One of the primary scientific discoveries from Solar Orbiter’s polar observations is that the solar magnetic field is currently disordered in the Antarctic region.
While traditional magnets exhibit defined Arctic and Antarctic poles, magnetic measurements from the PHI instrument demonstrate that both polarities exist in the Antarctic region of the Sun.
This phenomenon occurs only briefly during each solar cycle when the magnetic field is reversed at the solar maximum.
Following this reversal, a single polarity gradually takes over the solar pole.
After 5-6 years, the Sun reaches the minimum phase of its cycle, during which its magnetic field is most organized, resulting in the lowest activity levels.
“How this accumulation occurs is not fully understood, so the timing of the solar orbiter’s high latitude observations is remarkably advantageous for tracking the entire process,” noted Professor Solanki.
PHI’s perspective on the solar magnetic field contextualizes these measurements.
The intensity of color (red or blue) signifies the strength of the magnetic field along the line of sight from the solar orbiter to the Sun.
The strongest magnetic fields manifest as two bands flanking the solar equator.
Dark red and blue regions highlight areas of concentrated magnetic fields associated with solar spots on the Sun’s surface (photosphere).
Additionally, both the Antarctic and Arctic regions exhibit red and blue spots, indicating a complex, constantly evolving solar magnetic structure on a smaller scale.
Another noteworthy discovery from the Solar Orbiter comes from the SPICE instrument.
This imaging spectrograph analyzes light (spectral lines) emitted by specific chemical elements such as hydrogen, carbon, oxygen, neon, and magnesium, at known temperatures.
Over the last five years, SPICE has employed this method to uncover processes occurring in various layers of the Sun’s surface.
For the first time, the SPICE team was able to utilize precise spectral line tracing to measure the velocity of moving solar material.
This technique, known as “Doppler measurement,” is named after the effect observed with an ambulance siren as it approaches and recedes, causing a change in pitch.
The resulting velocity map illustrates the movement of solar material within specific solar layers.
“Measurements from high latitudes, made possible with the Solar Orbiter, will revolutionize solar physics,” stated Dr. Frederic Aucele, leader of the SPICE team at Paris Sacree University.
Astronomers have uncovered new phenomena occurring in the solar atmosphere, aided by remarkable new images of stars.
In a study conducted by Dark Schmidt and his team at the US National Solar Observatory, they utilized the California Good Solar Telescope to capture these images. By employing a technique known as adaptive optics, they minimized distortions caused by Earth’s atmosphere during solar observations, enabling them to examine the features of the corona, which is the outer atmosphere of stars.
“The level of detail is unprecedented; these are things that no one has ever observed before,” Schmidt states.
Plasma flows through the sun’s corona
Schmidt et al./njit/nso/aura/nsf
Newly revealed details include plasma flows within the corona and the plasma loops referred to as solar prominences.
The images also provide the clearest view of coronal rain observed to date, displaying plasma droplets about the size of cities falling toward the sun’s surface as they cool and become denser. “Gravity pulls them down toward the sun,” Schmidt explains.
The observations were conducted during the summers of 2023 and 2024. Researchers anticipate that some images will shed light on why the solar corona is significantly hotter than the solar surface—a difference of millions versus thousands of degrees, a perplexing enigma.
One theory involves the magnetic fields that interact and reconnect within the solar corona. “In numerous images and videos we present, you can observe intricately intertwined structures and chaotic movements at a minute scale,” notes Schmidt.
Some features captured in the images remain unexplained, such as a plasma filament splitting into multiple fragments. “Currently, we are missing a conclusive explanation,” Schmidt conveys. “This could indicate a novel phenomenon, and it’s thrilling to see how other scientists will further investigate this.”
A new “coronal adaptive optics” system has been developed by astronomers at the NSF’s National Solar Observatory and New Jersey Institute of Technology to generate high-resolution images and films by eliminating atmospheric blurring.
This image captures a 16-minute time-lapse film that illustrates the formation and collapse of a complex plasma stream measuring approximately 100 km per 100 km in front of a coronal loop system. This marks the first observation of such flows, referred to as plasmoids, raising questions about the dynamics involved. The image, taken by a Good Solar Telescope at Big Bear Solar Observatory with the new coronal adaptive optics system CONA, showcases hydrogen α light emitted by the solar plasma. While the image is artificially colored, it reflects the real color of hydrogen alpha light, with darker colors indicating bright light. Image credit: Schmidt et al. /njit /nso /aura /nsf.
The solar corona represents the outermost layer of the solar atmosphere, visible only during a total solar eclipse.
Astronomers have long been fascinated by its extreme temperatures, violent eruptions, and notable prominence.
However, Earth’s atmospheric turbulence has historically caused blurred images, obstructing the observation of the corona.
“Atmospheric turbulence, similar to the sun’s own dynamics, significantly degrades the clarity of celestial observations through telescopes. Fortunately, we have solutions,” stated Dr. Dark Schmidt, an adaptive optics scientist at the National Solar Observatory.
CONA, the adaptive optics system responsible for these advancements, corrects the atmospheric blurring affecting image quality.
This cutting-edge technology was funded by the NSF and implemented at the 1.6-meter Good Solar Telescope (GST) located at Big Bear Solar Observatory in California.
“Adaptive optics function similarly to autofocus and optical image stabilization technologies found in smartphone cameras, fixing atmospheric distortions rather than issues related to user instability,” explained Dr. Nicholas Golsix, optical engineer and lead observer at Big Bear Solar Observatory.
The second film depicts the rapid creation and collapse of a finely detailed plasma stream.
“These observations are the most detailed of their kind, highlighting features that were previously unobserved, and their nature remains unclear,” remarked Vasyl Yurchyshyn, a professor at the New Jersey Institute of Technology.
“Creating an instrument that allows us to view the sun like never before is incredibly exciting,” Dr. Schmidt commented.
Another film captures the dynamic movements across the solar surface, influenced by solar magnetism.
“The new Collar Adaptive Optical System closes the gap from decades past, delivering images of coronal features with resolution down to 63 km. This is the theoretical limit achievable with the 1.6 m Good Solar Telescope,” Dr. Schmidt stated.
“This technological leap is transformative. Discoveries await as we improve resolution tenfold,” he emphasized.
The team’s findings are detailed in a published paper in today’s issue of Nature Astronomy.
____
D. Schmidt et al. Observation of fine coronal structures with higher order solar adaptive optics. Nature Astronomy Published online on May 27, 2025. doi:10.1038/s41550-025-02564-0
Upon entering my department’s weekly Astro Coffee Journal Club some years ago, I was immediately struck by an existential crisis regarding the future of our planet.
Let me clarify; our discussion was not centered on the planet itself. Rather, we were delving into a newly published research paper detailing intriguing features in the light spectrum of very distant stars known as white dwarfs—or dead stars.
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While this white dwarf wouldn’t directly impact Earth, nor did its spectrum pose any particular threat, the paper did offer a peek into our Sun and, in turn, our own future in a somewhat terrifying manner.
First and foremost, rest assured that our sun won’t explode, contrary to popular belief. One prevalent astronomical misconception is the notion that our sun will eventually go supernova, ending in a dramatic explosion that engulfs our solar system.
Based on our knowledge of stellar evolution, this fate does not await our Sun at all.
There are two main routes for a star to go supernova: a nuclear collapse supernova, where a massive star exhausts its fusion fuel, collapses, and bounces back in a violent explosion, or when a stellar remnant interacts catastrophically with a companion star, annihilating both. Fortunately, our Sun is safe from these outcomes as it lacks the mass for nuclear collapse and doesn’t have a companion star.
Nonetheless, immortality isn’t in the cards for the Sun.
Presently, our sun operates as a massive fusion reactor, converting hydrogen into helium at its core and emitting vast energy. Although some energy escapes as light, the rest bounces inward off the plasma, creating pressure that counteracts gravitational collapse—similar to how air pressure shapes a balloon. For the next 5 billion years, the Sun will function normally, but as hydrogen depletes, its core will compress, triggering fusion of helium into heavier elements and causing the sun to swell and grow brighter.
At this point, the sun will become potent enough to evaporate Earth’s oceans, likely wiping out life. Mercury and Venus will face a more severe fate, swallowed by the expanding sun. The future of Earth is uncertain during this phase, known as the red giant phase, when the Sun ceases nuclear fusion and sheds its outer layers, potentially birthing stunning planetary nebulae.
As the core collapses, it forms a dense white dwarf star sustained by quantum mechanical processes rather than fusion. Eventually, all Sun-like stars end as white dwarfs, cooling and fading away.
In our journal club, researchers studied a white dwarf’s spectral lines and noted unexpected elements like calcium, potassium, and sodium—fragments likely from a devoured planet, a notion hauntingly depicted as blood on a predator’s jaw. This insight into contaminated white dwarfs evoked a sense of emotional calm and reflection.
Perhaps in the distant future, alien astronomers will gaze upon us, reminiscing about the once vibrant Earth. The contemplation of these cosmic phenomena leaves one pondering the impermanence of all things.
When I found out the date of the end of the Earth, everything seemed so simple. Five billion years from now, the solar system will have changed dramatically. Instead of the gentle presence we are accustomed to, the sun will become a behemoth, hundreds of times larger than it is today. In the process, it will wipe out the rocky inner planets, including our own.
Or will it be? We recently witnessed the death stages of another star for the first time. And miraculously, it seems some planets will be able to survive this apocalyptic era. Observations like these call into question the story of how the Earth will die, and give us hope that somehow the Earth may outlast the Sun. Even if it doesn’t, all is not lost. The study also provides clues as to where humans might best seek refuge.
How does the sun die?
The sun is powered by nuclear fusion. In nuclear fusion, hydrogen atoms fuse into helium, releasing a huge amount of energy in the process. However, the fate of our star is determined by one fact. This means that the supply of hydrogen is limited. As this energy begins to deplete, in about another 5 billion years, the Sun’s internal structure will change and it will expand to about 200 times its current size. It will change from the current yellow dwarf to a red giant. After another billion years, the star shrinks and expands again, before disappearing and becoming a stellar corpse called a white dwarf.
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