Amateur astronomers are monitoring a bright new comet easily detectable by backyard telescopes. Introducing, Comet SWAN25F:
"Newly-discovered Comet SWAN25F is brightening nicely as it approaches the sun," reports Mike Olason, who sends these pictures from Tucson, Arizona. "On the morning of April 6th, the comet was magnitude 8.4 with a bright green 3' wide coma and a thin tail that extended well beyond my field of view."

The comet is named after the SWAN camera onboard the Solar and Heliospheric Observatory (SOHO). Australian amateur astronomer Michael Mattiazzo noticed the comet in online images. SWAN is a special camera that maps hydrogen in the solar wind, which suggests this comet may be rich in the element.

Curtin University researchers have discovered the world's oldest known meteorite impact crater, which could significantly redefine our understanding of the origins of life and how our planet was shaped.

The team from Curtin's School of Earth and Planetary Sciences and the Geological Survey of Western Australia (GSWA) investigated rock layers in the North Pole Dome — an area of the Pilbara region of Western Australia — and found evidence of a major meteorite impact 3.5 billion years ago.

Study co-lead Professor Tim Johnson, from Curtin University, said the discovery significantly challenged previous assumptions about our planet's ancient history.

"Before our discovery, the oldest impact crater was 2.2 billion years old, so this is by far the oldest known crater ever found on Earth," Professor Johnson said.

Researchers discovered the crater thanks to 'shatter cones', distinctive rock formations only formed under the intense pressure of a meteorite strike.

The shatter cones at the site, about 40 kilometres west of Marble Bar in WA's Pilbara region, were formed when a meteorite slammed into the area at more than 36,000km/h.

This would have been a major planetary event, resulting in a crater more than 100km wide that would have sent debris flying across the globe.

If you want to travel to Alpha Centauri, it'll take thousands of years using current technology. It might be easier to wait. Astronomers have long known that the triple star system is approaching Earth for a close encounter 28,000 years from now. Indeed, a new study contends that asteroids from alpha Centauri are already here.

"We estimate that a million asteroid-sized objects from the alpha Centauri system could be in the Solar System right now," says Cole Gregg, a PhD student at the University of Western Ontario (UWO) and co-author of the study just accepted by the Planetary Science Journal. This simulation from the study shows asteroids entering the Solar System as alpha Centauri passes by:


Interest in alien asteroids spiked in 2017 when 'Oumuamua raced through the solar system. Prof. Avi Loeb from Harvard argued that the cigar-shaped object might be an alien spacecraft, but most astronomers went with Occam's Razor. It was more likely a natural body from another star system, they argued.

An international team of astronomers has investigated a newly detected Type II supernova designated SN 2024jlf. The new study, detailed in a paper published Jan. 30 on the arXiv pre-print server, yields important information regarding the evolution of this supernova and the nature of its progenitor.

Type II supernovae (SNe) are the results of rapid collapse and violent explosion of massive stars (with masses above 8.0 solar masses). They are distinguished from other SNe by the presence of hydrogen in their spectra.

Based on the shape of their light curves, they are usually divided into Type IIL and Type IIP. Type IIL SNe show a steady (linear) decline after the explosion, while Type IIP exhibit a period of slower decline (a plateau) that is followed by a normal decay.

SN 2024jlf was first spotted on May 28, 2024 using the Zwicky Transient Facility (ZTF), with a brightness of 15.88 mag. The supernova occurred in NGC 5690 — an edge-on spiral galaxy at a redshift of 0.0058.

Subsequent observations of SN 2024jlf after its discovery have revealed that its spectrum shows a blue continuum with weak flash features, indicating a young core-collapse supernova of Type II. A search for the progenitor of SN 2024jlf has also been conducted. However, no source has been identified in the location of this supernova.

The discovery marks only the second time that an asteroid's impact risk has reached greater than a 1% chance.
Astronomers — professional and amateur alike — have turned their attention to an asteroid with a slight chance of impacting Earth in 2032, based on current observations. While the possibility is slim, and more observations are needed, the object itself might be large enough to devastate a city, motivating follow-up observations as well as archival searches for pre-discovery observations.

The asteroid, designated 2024 YR4, was first noticed on December 27, 2024, by the Asteroid Terrestrial-impact Last Alert System (ATLAS); searches quickly revealed that ATLAS had already imaged it two days earlier. Then, as observations accumulated, astronomers could roughly determine its orbit. That's when the realization dawned: The object has some chance of striking Earth.

On Monday, January 27th, NASA's Sentry impact-tracking system officially raised the asteroid to a level 3 on the Torino scale. This is only the second time that an asteroid has merited a rating greater than 2 on the 10-point Torino scale, created in 1999 to convey the risk of an impact. At this level, an object has more than 1% chance of striking Earth.

Only one other object, asteroid 99942 Apophis, discovered in 2004, has ever reached that high on the scale. That asteroid peaked at 4, with a possibility of impact in 2029. But additional observations soon ruled that out, sending it back to a Torino rating of 0 — meaning no possible impact within the next century.

The chance of impact for 2024 YR4 is still slim: NASA's Jet Propulsion Laboratory estimates 1.2%. But if it does happen, German astronomer Daniel Bamberger (Northolt Branch Observatories) has used observations in hand to constrain the possible impact in time and location: The impact would take place on December 22, 2032, somewhere along a long line that extends from the Pacific Ocean off the coast of Mexico, through Ecuador and northern South America, across the Atlantic, through central Africa (from Kenya to Somalia), and then across to northern India.

The possible impact track covers big stretches of ocean as well as populated areas and some large cities. "I'd be really excited to see an impact," Bamberger says, "but I don't want it to be this one. Something over Antarctica, please!"

Astronomers analyzing archival images from JWST have discovered an unexpectedly vast population of the smallest asteroids ever seen in the asteroid belt between Mars and Jupiter.
Astronomers analyzing archival images from the James Webb Space Telescope (JWST) have discovered an unexpectedly vast population of the smallest asteroids ever seen in the asteroid belt between Mars and Jupiter. The finding could lead to better tracking of the tiny but powerful space rocks that are likely to approach Earth.

The newfound asteroids range in size from that of a bus to several stadiums — tiny compared to the massive space rock that wiped out most dinosaurs, but they nevertheless pack a significant punch. Only a decade ago an asteroid just tens of meters in size took everyone by surprise when it exploded over Chelyabinsk, Russia, and released 30 times more energy than the atomic bomb detonated over Hiroshima in WWII.

These so-called "decameter" asteroids collide with Earth 10,000 times more frequently than their larger counterparts, but their small size makes it challenging for surveys to detect them well in advance.

In recent years, a team of astronomers including Julien de Wit, an associate professor of planetary science at MIT, has been testing a computationally-intensive method to identify passing asteroids in telescope images of faraway stars.

By applying this method to thousands of JWST images of the host star in about 40 light-years distant TRAPPIST-1 system, which is the best-studied planetary system beyond our own, the researchers found eight previously known and 138 new decameter asteroids in the main asteroid belt. Among them, six appear to have been gravitationally nudged by nearby planets into trajectories that will bring them close to Earth. An early, unedited release of the findings was published Dec. 9 in the journal Nature.

"We thought we would just detect a few new objects, but we detected so many more than expected — especially small ones," de Wit said in a statement. "It is a sign that we are probing a new population regime."

Several brief flashes on the lunar surface were captured from Earth.
As we approach the peak of the Geminid meteor shower overnight on Friday (Dec. 13), the skies are beginning to light up with impressive meteors striking Earth's atmosphere. But Earth isn't the only target; the moon is regularly bombarded with such meteors, and Daichi Fujii, the curator of the Hiratsuka City Museum in Japan, has captured some of the most recent collisions.

Fujii documented meteor impacts on the moon on Dec. 6, Dec. 7 and twice on Dec. 8, 2024, using cameras set to monitor Earth's nearest neighbor. You can view some of his lunar impact videos (as well as some impressive fireballs) on his X account.

"There was another lunar impact flash tonight. I filmed it at 360fps from my home at 22:34:35 on December 8, 2024 (slow playback) and was able to confirm it with multiple telescopes. Bright meteors and fireballs have been appearing every day, but lunar impact flashes have also been captured one after another," Fujii wrote in a post on X on Dec. 8.

A new view of archival Webb telescope data reveals small asteroids in the main asteroid belt are more numerous than we thought.

Astronomers have uncovered an unexpectedly large population of small main-belt asteroids thanks to a new analysis of images from the James Webb Space Telescope. The finding could change calculations of the impact rate on Earth from such bodies, which range from house-size to the size of a stadium.

These are by far the smallest objects ever imaged so far away. Artem Burdanov (MIT) and colleagues applied a computationally intensive shift-and-stack method to Webb's archival images. From the telescope's sensitive infrared detectors, the team was able to accurately determine the sizes of small objects, ranging from about 10 to 500 meters (30 to 1,600 feet) across. An early release of their results appears in Nature.

Larger main-belt asteroids, whose orbits are between those of Mars and Jupiter, tend to remain in relatively stable orbits. However, gravitational interactions more frequently perturb smaller ones, which may enter the inner solar system to become potential impactors. The high number of small objects now found in the main belt — more than an order of magnitude greater than expected — could affect calculations of the frequency of such impacts.

This 2013 astronaut photo shows a giant eye-shaped impact crater in the Sahara Desert that is slowly being circled by migrating sand dunes, helping researchers track how far these dunes can move over time.
This striking astronaut photo shows off an "eye-catching" impact crater in the Sahara Desert. The oculus-like structure is surrounded by migrating sand dunes that are capable of traveling more than 100 feet (30 meters) every year.

The Aorounga structure is a 7.8-mile-wide (12.6 kilometers) impact crater located in the southeast Sahara in northern Chad. The crater is made up of two rings that give the structure its eye-like appearance: An inner ring with a central hill, or uplift structure, that looks like a pupil; and an outer ring that looks like an eyelid. The rings rise around 330 feet (100 m) above the surrounding ground but have been heavily eroded over time — similar to other ancient impact craters — and were likely even taller and wider originally.

Experts believe that the structure formed around 345 million years ago and was likely created by a meteor around 2,000 feet (600 m) across, according to estimates from the Lunar and Planetary Institute. An impactor of this size, known as a "city-killer" asteroid, would have caused widespread damage across the north of Africa and may have even triggered climatic effects on a global scale.

The structure also has several dark lines running across both of its rings, which are sections of massive ridges, known as yardangs, according to the U.S. Geological Survey. These ridges, which can reach up to 100 feet (30 m) above ground level, stretch across the surrounding areas for dozens of miles, as you can see in the 2016 astronaut images below.

Comet C/2024 S1 (ATLAS) is no more.

On Monday (Oct. 28), the comet evaporated as it was heading toward perihelion, the closest point to the sun in its orbit. There were earlier hopes that the comet, officially designated C/2024 S1 (ATLAS), could become a "Halloween treat" visible to the naked eye, but these were ultimately just wishful thinking; astronomers had already begun observing the cosmic snowball beginning to disintegrate earlier this month.


Now, thanks to the Solar and Heliospheric Observatory (SOHO), a spacecraft jointly operated by NASA and the European Space Agency, we know for sure how and when comet ATLAS met its demise.

Comet C/2024 S1 (ATLAS) passed its closest point to Earth on Oct. 23, reaching a magnitude of 8.7, far too dim to be seen with the naked eye. Still, telescopes were able to catch a glimpse of the icy visitor from the outer solar system.

After that approach, the comet began flying toward the sun, making it difficult to see by anything other than specialized instruments designed for solar observations.