An agreement between NASA and the U.S. Space Force recently authorized the public release of decades of data collected by U.S. government sensors on fireball events (large bright meteors also known as bolides) for the benefit of the scientific and planetary defense communities. This action results from collaboration between NASA's Planetary Defense Coordination Office (PDCO) and the U.S. Space Force to continue furthering our nation's efforts in planetary defense, which include finding, tracking, characterizing, and cataloguing near-Earth objects (NEOs). The newly released data is comprised of information on the changing brightness of bolides as they pass through Earth's atmosphere, called light curves, that could enhance the planetary defense community's current ability to model the effects of impacts by larger asteroids that could one day pose a threat to Earth.

Bolides, very bright meteors that can even be seen in daylight, are a regular occurrence - on the order of several dozen times per year - that result when our planet is impacted by asteroids too small to reach the ground but large enough to explode upon impact with Earth's atmosphere. U.S. government sensors detect these atmospheric impact events, and the bolide data is reported to the NASA Jet Propulsion Laboratory's Center for Near Earth Object Studies (CNEOS) fireballs database, which contains data going back to 1988 for nearly one thousand bolide events. Now, planetary defense experts will have access to even more detailed data - specifically, light curve information that captures the optical intensity variation during the several seconds of an object's breakup in the atmosphere. The data will be available to scientists as soon as it is properly archived, with the reported events and made easily accessible. This uniquely rich data set has been greatly sought after by the scientific community as an object's breakup in Earth's atmosphere provides scientific insight into the object's strength and composition based on what altitudes at which it breaks up and disintegrates. The approximate total radiated energy and pre-entry velocity vector (i.e., direction) can also be better derived from bolide light curve data.

"The growing archive of bolide reports, as posted on the NASA CNEOS Fireballs website, has significantly increased scientific knowledge and contributes to the White House approved National Near-Earth Object Preparedness Strategy and Action Plan" said Lindley Johnson, planetary defense officer at NASA Headquarters. "The release of these new bolide data demonstrates another key area of collaboration between NASA and the U.S. Space Force and helps further the pursuit of improved capabilities for understanding these objects and our preparedness to respond to the impact hazard NEOs pose to Earth."

CBET 5111 & MPEC 2022-F13, issued on 2022, March 21, announce the discovery of an apparently asteroidal object (magnitude ~17) discovered on CCD images taken on Mar. 2 UT with a 1.2-m f/2.4 Schmidt telescope at Palomar in the course of the "Zwicky Transient Facility" (ZTF) survey (MPC code I41). Subsequently, it has been found to show cometary appearance by CCD astrometrists elsewhere. The new comet has been designated C/2022 E3 (ZTF).

Stacking of 12 unfiltered exposures, 120 seconds each, obtained remotely on 2022, March 20.4 from X02 (Telescope Live, Chile) through a 0.61-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact coma about 9" arcsecond in diameter (Observers E. Guido, M. Rocchetto, E. Bryssinck, G. Milani, G. Savini, A. Valvasori).

Our confirmation image (click on the images for a bigger version; made with TYCHO software by D. Parrott)

CBET 5109 & MPEC 2022-E227, issued on 2022, March 15, announce the discovery of an apparently asteroidal object (magnitude ~19) discovered on CCD images taken on Mar. 7 UT with a 0.5-m f/2 Schmidt reflector at Rio Hurtado, Chile, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program. Subsequently, it has been found to show cometary appearance by CCD astrometrists elsewhere after it was posted on the Minor Planet Center's PCCP webpage. The new comet has been designated C/2022 E2 (ATLAS).

Stacking of 25 unfiltered exposures, 120 seconds each, obtained remotely on 2022, March 10.3 from X02 (Telescope Live, Chile) through a 0.61-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact coma about 7" arcsecond in diameter (Observers E. Guido, M. Rocchetto, E. Bryssinck, G. Milani, G. Savini, A. Valvasori).

Our confirmation image (click on the images for a bigger version; made with TYCHO software by D. Parrott)

On 2022 March 11.80, K. Sarneczky found a small asteroid using the 0.60-m Schmidt + CCD of GINOP-KHK, Piszkesteto (K88 MPC code) that was soon after put on the NEOCP list with the provisional designation Sar2593 for the follow-up by other observers. The Minor Planet Center subsequently assigned the following official designation to this object 2022 EB5.

Discovery images (19:25UT) of asteroid 2022 EB5

Credit: K. Sarneczky

At 20:46UT of March 11, Bill Gray sent an alert in the MPML mailing list about the impact of Sar2593 with the Earth's atmosphere and: "to urge European observers to take a look for this object, currently on NEOCP. It should come in at 21:23 UTC at latitude +70.47, longitude W 10.40, plus or minus a few dozen km. That's about forty minutes from "right now", a bit north of Iceland". Below you can see a map of the impact location as calculated by Gray, southwest of Jan Mayen island.

Danish and Swedish researchers have dated the enormous Hiawatha impact crater, a 31 km-wide asteroid crater buried under a kilometer of Greenlandic ice. The dating ends speculation that the asteroid impacted after the appearance of humans and opens up a new understanding of Earth's evolution in the post-dinosaur era.

Ever since 2015, when researchers at the University of Copenhagen's GLOBE Institute discovered the Hiawatha impact crater in northwestern Greenland, uncertainty about the crater's age has been the subject of considerable speculation. Could the asteroid have slammed into Earth as recently as 13,000 years ago, when humans had long populated the planet? Could its impact have catalyzed a nearly 1,000-year period of global cooling known as the Younger Dryas?

New analyses performed on grains of sand and rocks from the Hiawatha impact crater by the Natural History Museum of Denmark and the GLOBE Institute at the University of Copenhagen, as well as the Swedish Museum of Natural History in Stockholm, demonstrate that the answer is no. The Hiawatha impact crater is far older. In fact, a new study published in the journal Science Advances today reports its age to be 58 million years old.

"Dating the crater has been a particularly tough nut to crack, so it's very satisfying that two laboratories in Denmark and Sweden, using different dating methods arrived at the same conclusion. As such, I'm convinced that we've determined the crater's actual age, which is much older than many people once thought," says Michael Storey of the Natural History Museum of Denmark.

Asteroid 2020 XL5 will be Earth's buddy for the next 4,000 years.

A rocky body spotted orbiting in Earth's path is a "Trojan asteroid" that escorts our planet around the sun, astronomers have confirmed.

Asteroid 2020 XL5 is the second Trojan asteroid ever discovered. It's three times larger than the only other known Earth Trojan, called Asteroid 2010 TK7, which was confirmed in 2011. These small space rocks orbit along with Earth, but they are hard to spot from our planet — Asteroid 2010 TK7 is sometimes on the other side of the sun from us. They sit in gravitational sweet spots known as Lagrangian points. If Earth and the sun make up two points of an equilateral triangle, the Lagrangian point would be that triangle's third point. Earth and the sun have five of these points.

The newfound Trojan is at a Lagrangian point that has it orbiting ahead of Earth in the two bodies' shared path and the asteroid will stay there for 4,000 more years, researchers reported Tuesday (Feb. 1) in the journal Nature Communications. The asteroid is probably about 0.7 miles (1.18 kilometers) in diameter, though that estimate may be off if the surface of the asteroid is more or less reflective than astronomers assume.

UC researchers find evidence of cosmic cataclysm 1,500 years ago at 11 ancient sites.
The rapid decline of the Hopewell culture about 1,500 years ago might be explained by falling debris from a near-Earth comet that created a devastating explosion over North America, laying waste to forests and Native American villages alike.

Researchers with the University of Cincinnati found evidence of a cosmic airburst at 11 Hopewell archaeological sites in three states stretching across the Ohio River Valley. This was home to the Ohio Hopewell, part of a notable Native American culture found across what is now the eastern United States.

The comet's glancing pass rained debris down into the Earth's atmosphere, creating a fiery explosion. UC archaeologists used radiocarbon and typological dating to determine the age of the event.

The airburst affected an area bigger than New Jersey, setting fires across 9,200 square miles between the years A.D. 252 and 383. This coincides with a period when 69 near-Earth comets were observed and documented by Chinese astronomers and witnessed by Native Americans as told through their oral histories.

The study was published in the Nature journal Scientific Reports.

New research shows it's the composition of the rock a meteorite hits, and not the impactor's size, that causes an extinction-level event.
It's a well-known story in our planet's past: A giant space rock slams into Earth, causing a catastrophe that ends in mass extinction. You might think that when it comes to determining which hits will cause such widespread devastation, the size of the incoming impactor is what matters. But new research suggests that something else might matter more: The composition of the ground where that meteorite hits.

The work, published Dec. 1, 2021, in Journal of the Geological Society, focuses on explaining why some meteorite impacts cause mass extinctions, while others don't. For example, the famous impact that killed the dinosaurs and left the Chicxulub crater was much smaller than many other impact events that didn't cause massive loss of species. Why might this be?

Could a curious geological formation in the Mauritanian part of the Sahara desert anything to do with the lost city of Atlantis?

If you type the word "Atlantis" into Google, around 120 million results will pop up. Obviously, Plato's legend of Atlantis has long occupied many people, from scientists to mysticists, with many candidates being cited as the possible location of this lost and sunken civilization. But did such a city ever exist at all? And if yes, where could the ruins be?

The only mention of Atlantis by name in historical texts is in Plato's Dialogues (written around 360 B.C.), which gives dozens of precise details about what Atlantis looked like, and where it may have been located in relation to other landmarks in the ancient world. It was this level of detail that has set many people off thinking that Atlantis actually existed.

One of the best clues that Plato gives about Atlantis is that there was a series of concentric circles around the city, black and red stone, and of course it was a seafaring society:

Poseidon carved the mountain where his love dwelt into a palace and enclosed it with three circular moats of increasing width, varying from one to three stadia and separated by rings of land proportional in size. The Atlanteans then built bridges northward from the mountain, making a route to the rest of the island. They dug a great canal to the sea, and alongside the bridges carved tunnels into the rings of rock so that ships could pass into the city around the mountain; they carved docks from the rock walls of the moats. Every passage to the city was guarded by gates and towers, and a wall surrounded each ring of the city. The walls were constructed of red, white, and black rock, quarried from the moats, and were covered with brass, tin, and the precious metal orichalcum, respectively.

So, according to Plato, Atlantis looked something like this:

Something strange is happening to skywatchers' most anticipated comet of the year.

Astronomers first spotted what's been dubbed Comet Leonard in January 2021, and soon skywatchers were eagerly anticipating December and January, when the comet was due to pass by first Earth, then the sun. But by late November, observers noticed something strange. The comet should be getting brighter as it approaches the sun — and it is, but apparently only because it's getting closer to Earth, not because it's becoming inherently brighter.

Instead, it seems to be fading.