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Explanation: Messier 15 is an immense swarm of over 100,000 stars. A 13 billion year old relic of the early formative years of our galaxy it's one of about 170 globular star clusters that still roam the halo of the Milky Way. Centered in this sharp reprocessed Hubble image, M15 lies some 35,000 light-years away toward the constellation Pegasus. Its diameter is about 200 light-years, but more than half its stars are packed into the central 10 light-years or so, making one of the densest concentrations of stars known. Hubble-based measurements of the increasing velocities of M15's central stars are...

3I/ATLAS, as seen by the Gemini South observatory in August 2025 (Credit: International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist). ============================================================================ Physicists have detected water activity during observations of the mysterious comet 3I/ATLAS, marking the first time hydroxyl gas, a chemical signature of water, has been detected from the interstellar visitor. Using NASA’s Neil Gehrels Swift Observatory, the Auburn University team determined 3I/ATLAS is releasing water at a rate of roughly 40 kilograms per second, comparable to a fire hose running at full blast, while positioned nearly three times farther from the Sun than Earth. What makes this finding particularly remarkable is the...

Explanation: What's happening to this spiral galaxy? Just a few hundred million years ago, NGC 2936, the upper of the two large galaxies shown at the bottom, was likely a normal spiral galaxy -- spinning, creating stars -- and minding its own business. But then it got too close to the massive elliptical galaxy NGC 2937, just below, and took a turn. Sometimes dubbed the Hummingbird Galaxy for its iconic shape, NGC 2936 is not only being deflected but also being distorted by the close gravitational interaction. Behind filaments of dark interstellar dust, bright blue stars form the nose of...

A small asteroid narrowly missed Earth over Antarctica, passing within the altitude of the International Space Station. Credit: Shutterstock ===================================================================== Asteroid 2025 TF zoomed over Antarctica just 266 miles above Earth, roughly the same height as the ISS. Detected only hours later, the 1–3 meter rock posed no threat but provided valuable data for astronomers. Close Encounter Over Antarctica In the early hours of October 1, Asteroid 2025 TF swept over Antarctica at 00:47:26 UTC ± 18 seconds, passing within just 428 ± 7 km (266 ± 4 miles) of Earth’s surface. That distance places it nearly at the same...

Astronomers from Princeton may have found evidence of a hidden planet -- Planet Y -- orbiting in the far reaches of the Solar System. Could this be the missing world shaping the Kuiper Belt? Watch to find out. A New Planet Discovered? Planet 9 Has a Rival -- Meet Planet Y | 9:45 NASA Space News | 556K subscribers | 28,062 views | October 6, 2025 Chapters: 00:00 Introduction 00:38 The Discovery 03:04 Scientific Importance and Theories 05:30 Implications and What’s Next 08:29 Outro 08:43 Enjoy

Explanation: Is this one galaxy or two? This question came to light in 1950 when astronomer Arthur Hoag chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older. Between the two is a gap that appears almost completely dark. How Hoag's Object formed, including its nearly perfectly round ring of stars and gas, remains unknown. Genesis hypotheses include a galaxy collision billions of years ago and the gravitational effect of a central bar that has since vanished....

Chatter Points * A new model suggests dark matter and dark energy may not be real entities, but effects of changing physical constants. * Galaxy rotation curves from seven galaxies fit the model using one key parameter: a “turn-off density.” * The approach also explains supernovae, galaxy clusters, and the cosmic microwave background without exotic matter. * Challenges remain: galaxies are complex, and no direct evidence yet shows that fundamental constants truly vary. ========================================================================== A physicist at the University of Ottawa has published research suggesting the universe’s most perplexing mysteries — dark matter and dark energy, which together supposedly account...

The retracted study concerned GFAJ-1, a bacterium collected in Mono Lake's arsenic-filled waters by Felisa Wolfe-Simon, then a researcher at the NASA Astrobiology Institute and the U.S. Geological Survey. Citing experiments on the microbe, she and colleagues suggested it used the normally toxic element in place of phosphorus to make DNA and proteins. A NASA release claimed the discovery "broadens our thinking about the possibility of life on other planets, and begs a rewrite of biology textbooks." But the work swiftly attracted challenges by other researchers, and attempts to replicate it failed...After controversy sparked by the paper's online publication delayed...

Recent images purportedly depicting the interstellar comet 3I/ATLAS during its closest approach to Mars last week have erupted in controversy online, as many took to social media with theories about what the object’s unusual shape could mean about its nature and origins. The new images obtained last week by NASA’s Perseverance rover appear to show 3I/ATLAS streaking through the Martian night sky as it passed through the field of view of the robotic explorer’s Right Navigation Camera (Navcam) from its position in Jezero Crater. The recent imagery was originally uploaded to NASA’s multimedia page in raw format. Since that time,...

Explanation: The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy. Even at some two and a half million light-years distant, this immense spiral galaxy -- spanning over 200,000 light years -- is visible, although as a faint, nebulous cloud in the constellation Andromeda. In contrast, a bright yellow nucleus, dark winding dust lanes, and expansive spiral arms dotted with blue star clusters and red nebulae, are recorded in this stunning telescopic image which combines data from orbiting Hubble with ground-based images from Subaru and Mayall. In only about 5 billion years, the Andromeda...

According to the team the polarimetric behavior is "significantly different from all known comets (either interstellar or bound to our Solar System)". 3I/ATLAS imaged by NASA’s Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx). Image credit: NASA/SPHEREx. ================================================================= Ateam of astronomers have presented the first polarimetric observations of interstellar comet 3I/ATLAS, finding that it has extreme negative polarization. On July 1, 2025, astronomers spotted an object moving through the Solar System at nearly twice the velocity of previous interstellar visitors ‘Oumuamua and Comet Borisov. The object was confirmed to be an interstellar comet with...

Explanation: Spanning the sky behind the majestic Clouds of Magellan is an unusual stream of gas: the Magellanic Stream. The origin of this gas might hold a clue to origin and fate of our Milky Way's most famous satellite galaxies: the LMC and the SMC. Two leading genesis hypotheses have surfaced: that the stream was created by gas stripped off these galaxies as they passed through the halo of our Milky Way, or that the stream was created by the differential gravitational tug of the Milky Way. Measurements of slight angular motions by the Hipparcos satellite have indicated that the...

Space can surprise even those who spend their lives studying it. People often think of our solar system as just a few planets and a bunch of empty space. Yet new observations suggest we have been living inside a hot, less dense region, and that there may even be a strange cosmic channel connecting us to distant stars. After years of careful mapping, a new analysis reveals what appears to be a channel of hot, low-density plasma stretching out from our solar system toward distant constellations. Astronomers from the Max Planck Institute recently confirmed it using data from the eRosita...

Explanation: Big, beautiful, barred spiral galaxy NGC 1300 lies some 70 million light-years away on the banks of the constellation Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the largest Hubble images ever made of a complete galaxy. NGC 1300 spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy's dominant central bar and majestic spiral arms. In fact, on close inspection the nucleus of this classic barred spiral itself shows a remarkable region of spiral structure about 3,000 light-years across. Like other spiral galaxies, including our own Milky...

Explanation: The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the red emission nebula in the center of the above photograph. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula's red color is caused by electrons recombining with protons to form...

Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way galaxy. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Assembled from 51 exposures recorded by the Hubble Space Telescope in the 20th and 21st centuries, with additional data from ground based telescopes, this mosaic of M101 is touted as the largest, most detailed spiral galaxy view...

Explanation: Galaxies like colorful pieces of candy fill the Hubble Ultra Deep Field 2014. The dimmest galaxies are more than 10 billion times fainter than stars visible to the unaided eye and represent the Universe in the extreme past, a few 100 million years after the Big Bang. The image itself was made with the significant addition of ultraviolet data to the Hubble Ultra Deep Field, an update of Hubble's famous most distant gaze toward the southern constellation of Fornax. It now covers the entire range of wavelengths available to Hubble's cameras, from ultraviolet through visible to near-infrared. Ultraviolet data...

Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light would suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant. This sharp telescopic view is centered on a western segment of the Veil Nebula cataloged as NGC 6960 but less formally known as the Witch's Broom Nebula. Blasted out in the cataclysmic explosion, an interstellar shock wave plows through space sweeping up and exciting interstellar material....

Explanation: Comet Lemmon is brightening and moving into morning northern skies. Besides Comet SWAN25B and Comet ATLAS, Comet C/2025 A6 (Lemmon) is now the third comet currently visible with binoculars and on long camera exposures. Comet Lemmon was discovered early this year and is still headed into the inner Solar System. The comet will round the Sun on November 8, but first it will pass its nearest to the Earth -- at about half the Earth-Sun distance -- on October 21. Although the brightnesses of comets are notoriously hard to predict, optimistic estimates have Comet Lemmon then becoming visible to...

A lunar impact could generate debris that damages key satellites, the ISS…and potentially any lunar installations that had been constructed as part of the new space race. Asteroid 2024 YR4 is a near-Earth object approximately 53–67 meters wide that was discovered in December 2024. While initial models suggested a small chance of Earth impact, refined tracking now indicates that there is no risk to Earth, but about a 4% probability that it will strike the Moon on December 22, 2032. Earlier this year, asteroid 2024 YR4 drew global attention when its estimated chance of striking Earth in 2032 reached 3%....