Every day, thousands of small rocks — dust grain- to pebble-sized — cross paths with Earth's atmosphere and burn up. More organized collisions, known as meteor showers, are visible to us when the planet passes through whole clouds of rocky debris.

These fragments were long thought to come strictly from comets whose crusts had been heated by the Sun and cracked open. But early in 2019, NASA's OSIRIS-Rex spacecraft (short for Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) captured images from the near-Earth asteroid Bennu that flipped that line of thinking on its head.

The images showed small bits of rock launching off the asteroid's surface. Some of the rock fell back to the surface and some went into orbit around Bennu for several days, but about 30 percent was ejected with enough speed that its pieces escaped the asteroid's gravity and began to orbit around the Sun.

"This was surprising," says Robert Melikyan, a graduate student at the University of Arizona's Lunar and Planetary Laboratory. "Bennu doesn't have a lot of volatile material that can heat up and break up the way comets do."

Melikyan and a team of researchers modeled the evolution of the asteroid's dust cloud in a study published in the Journal of Geophysical Research: Planets earlier this year and found that the particles both spread out around Bennu's orbit and follow a similar elliptical path around the Sun.

Hello and welcome! My name is Anton and in this video, we will talk about a detection of a bolide explosion in Chile 12000 years ago.


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Widespread glasses generated by cometary fireballs during the late Pleistocene in the Atacama Desert, Chile

81P/Wild

Heat from a comet exploding just above the ground fused the sandy soil into patches of glass stretching 75 kilometers, a study led by Brown University researchers found.
PROVIDENCE, R.I. — Around 12,000 years ago, something scorched a vast swath of the Atacama Desert in Chile with heat so intense that it turned the sandy soil into widespread slabs of silicate glass. Now, a research team studying the distribution and composition of those glasses has come to a conclusion about what caused the inferno.

In a study published in the journal Geology, researchers show that samples of the desert glass contain tiny fragments with minerals often found in rocks of extraterrestrial origin. Those minerals closely match the composition of material returned to Earth by NASA's Stardust mission, which sampled the particles from a comet called Wild 2. The team concludes that those mineral assemblages are likely the remains of an extraterrestrial object — most likely a comet with a composition similar to Wild 2 — that streamed down after the explosion that melted the sandy surface below.

"This is the first time we have clear evidence of glasses on Earth that were created by the thermal radiation and winds from a fireball exploding just above the surface," said Pete Schultz, a professor emeritus in Brown University's Department of Earth, Environmental and Planetary Sciences. "To have such a dramatic effect on such a large area, this was a truly massive explosion. Lots of us have seen bolide fireballs streaking across the sky, but those are tiny blips compared to this."

CBET 5064 & MPEC 2021-V21, issued on 2021, November 02, announce the discovery of a new comet (magnitude ~19) by A. Maury and G. Attard on CCD images taken on October 24.3 UT with the 0.28-m f/2.2 Rowe-Ackermann Schmidt astrograph at San Pedro de Atacama, Chile in the course of the MAP (W94) survey. The new comet has been designated P/2021 U3 (Attard-Maury). This is the 4th amateur comet discovery of 2021. It is also the second comet discovered using the synthetic tracking technique (using TYCHO software).

Stacking of 51 unfiltered exposures, 60 seconds each, obtained remotely on 2021, Oct. 27.3 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 6" arcsecond in diameter and a tail 6" long in PA 275 (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Stacking of 66 unfiltered exposures, 60 seconds each, obtained remotely on 2021, Oct. 29.9 from G18 (ALMO Observatory, Italy) through a 0.30-m f/4 reflector + CCD, shows that this object is a comet with a compact coma about 5" arcsec in diameter and a tail 6" long in PA 270 (Observers A. Valvasori & E. Guido).

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

You wake up to a dark, dreary, glum-feeling, Monday-type of morning. For the 547th consecutive day.

Just 18 months prior, you were a hard-working farmer gearing up for another bountiful crop season.

But then the skies went dark.

From early 536 to 537, they stayed dark. Across much of eastern Europe and throughout Asia, spring turned into summer and fall gave way to winter without a day of sunshine. Like a blackout curtain over the sun, millions of people across the world's most populated countries squinted through dim conditions, breathing in chokingly thick air and losing nearly every crop they were relying on to harvest.

This isn't the plot of a dystopian TV drama or a fantastical "docufiction" production.

This was a harsh reality for the millions of people that lived through that literally dark time or, as some historians have declared, the very worst year ever to be alive.

A team led by Southwest Research Institute has updated its asteroid bombardment model of the Earth with the latest geologic evidence of ancient, large collisions. These models have been used to understand how impacts may have affected oxygen levels in the Earth's atmosphere in the Archean eon, 2.5 to 4 billion years ago.

When large asteroids or comets struck early Earth, the energy released melted and vaporized rocky materials in the Earth's crust. The small droplets of molten rock in the impact plume would condense, solidify and fall back to Earth, creating round, globally distributed sand-size particles. Known as impact spherules, these glassy particles populated multiple thin, discrete layers in the Earth's crust, ranging in age from about 2.4 to 3.5 billion years old. These Archean spherule layers are markers of ancient collisions. "In recent years, a number of new spherule layers have been identified in drill cores and outcrops, increasing the total number of known impact events during the early Earth," said Dr. Nadja Drabon, a professor at Harvard University and a co-author of the paper.

"Current bombardment models underestimate the number of late Archean spherule layers, suggesting that the impactor flux at that time was up to 10 times higher than previously thought," said SwRI's Dr. Simone Marchi, lead author of a paper about this research in Nature Geoscience. "What's more, we find that the cumulative impactor mass delivered to the early Earth was an important 'sink' of oxygen, suggesting that early bombardment could have delayed oxidation of Earth's atmosphere."

The abundance of oxygen in Earth's atmosphere is due to a balance of production and removal processes. These new findings correspond to the geological record, which shows that oxygen levels in the atmosphere varied but stayed relatively low in the early Archean eon. Impacts by bodies larger than six miles (10 km) in diameter may have contributed to its scarcity, as limited oxygen present in the atmosphere of early Earth would have been chemically consumed by impact vapors, further reducing its abundance in the atmosphere.

American cosmic airburst in late Roman times revealed by Tankersly and Saniel-Banrey of University of Cincinnati.

Meteorites, silicious vesicular melt glass, Fe and Si-rich magnetic spherules, positive Ir and Pt anomalies, and burned charcoal-rich Hopewell habitation surfaces demonstrate that a cosmic airburst event occurred over the Ohio River valley during the late Holocene. A comet-shaped earthwork was constructed near the airburst epicenter. Twenty-nine radiocarbon ages demonstrate that the event occurred between 252 and 383 CE, a time when 69 near-Earth comets were documented. While Hopewell people survived the catastrophic event, it likely contributed to their cultural decline. The Hopewell comet airburst expands our understanding of the frequency and impact of cataclysmic cosmic events on complex human societies.

Abstract — The Hopewell airburst event, 1699-1567 years ago(252-383 CE) — october 13, 2021

A group of Japanese astronomers just discovered a potential new impact at the planet Jupiter.
Get your scorecards out — Jupiter just took another interplanetary hit. If it's confirmed it would be the 11th observed comet or asteroid strike at the gas giant since the pieces of Comet Shoemaker-Levy 9 slammed into Jupiter in 1994.

A little more than a month after five amateurs independently recorded a similar flash, a team of astronomers, led by Ko Arimatsu of Kyoto University, filmed this most recent flare in Jupiter's cloud tops at 13:24 UT on Friday, October 15th.

The potential impact flash appears around the 12-second mark in this video of Jupiter made on Friday, October 15th.
Ko Arimatsu / Kyoto University

A mega-comet - potentially the largest ever discovered - is heading from the Oort Cloud towards our direction. Estimated to be 100-200 kilometers across, the unusual celestial wanderer will make its closest approach to the Sun in 2031. However, the closest it will come to Earth is to the orbit of Saturn.

Astronomers say Comet Bernardinelli-Bernstein (C/2014 UN271) could be the largest member of the Oort Cloud ever detected, and it is the first comet on an incoming path to be detected so far away.

The graphic above, by astronomer Will Gater compares the size of the comet to other Solar System objects.

The comet was discovered Pedro Bernardinelli and Gary Bernstein, from the University of Pennsylvania earlier this year. They were scouring through data from the 570-megapixel Dark Energy Camera (DECam) on the Víctor M. Blanco 4-meter Telescope in Chile. They found data of this object that was originally collected from 2014-2018, which did not show a typical comet tail, and the object was therefore thought to be a dwarf planet.

But within a day of the announcement of its discovery via the Minor Planet Center, astronomers using the Las Cumbres Observatory network took new images which revealed that it has grown a coma in the past 3 years, and that it was rapidly moving rapidly through the Oort Cloud. The object was then officially classified as a comet.

CBET 5029 & MPEC 2021-R98 , issued on 2021, September 06, announce the discovery of a new comet (magnitude ~17) on CCD images taken on August 29.6 UT with a 0.5-m f/2 Schmidt reflector at Haleakala, Hawaii, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program. The new comet has been designated P/2021 Q5 (ATLAS).

Stacking of 58 unfiltered exposures, 30 seconds each, obtained remotely on 2021, September 03.1 from G18 (ALMO Observatory, Italy) through a 0.30-m f/4 reflector + CCD, shows that this object is a comet with a compact coma about 8" arcsec in diameter and a tail 10" long in PA 270 (Observers A. Valvasori & E. Guido).

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