Catch one of the most active small bodies in the solar system during a rare superoutburst.

A comet infamous for its explosive personality has been in near-continuous outburst since September 25th. The brightness of Comet 29P/Schwassmann-Wachmann is steadily rising, and it now appears as a tiny, 11th-magnitude object easily visible in 8-inch and larger telescopes. If you've never seen a comet masquerade as a star-like planetary nebula, don't pass up the chance — look soon. As the outburst evolves the comet's coma will expand but also fade.

The scientists that found Comet Bernardinelli-Bernstein are an unlikely pair.

Even Pedro Bernardinelli and Gary Bernstein admit they're an unlikely pair of scientists to end up with a record-breaking comet named in their honor.

Scientists briefly estimated that Comet Bernardinelli-Bernstein, as it's now known, was the largest such icy body identified to date, perhaps more than 100 miles (160 kilometers) across. Additional observations have cast that into doubt, but given the "megacomet" a new distinction: it sprouted a tail remarkably far from the sun, suggesting more revelations to come. All told, the object offers astronomers an unprecedented opportunity to watch the antics of a comet.

A study published in the journal Geology rules out that extreme volcanic episodes had any influence on the massive extinction of species in the late Cretaceous. The results confirm the hypothesis that it was a giant meteorite impact what caused the great biological crisis that ended up with the non-avian dinosaur lineages and other marine and terrestrial organisms 66 million years ago.

The study was carried out by the researcher Sietske Batenburg, from the Faculty of Earth Sciences of the University of Barcelona, and the experts Vicente Gilabert, Ignacio Arenillas and José Antonio Arz, from the University Research Institute on Environmental Sciences of Aragon (IUCA-University of Zaragoza).

K/Pg boundary: the great extinction of the Cretaceous in Zumaia coasts

The scenario of this study were the Zumaia cliffs (Basque Country), which have an exceptional section of strata that reveals the geological history of the Earth in the period of 115-50 million years ago (Ma). In this environment, the team analyzed sediments and rocks that are rich in microfossils that were deposited between 66.4 and 65.4 Ma, a time interval that includes the known Cretaceous/Paleogene boundary (K/Pg). Dated in 66 Ma, the K/Pg boundary divides the Mesozoic and Cenozoic eras and it coincides with one of the five large extinctions of the planet.

This study analysed the climate changes that occurred just before and after the massive extinction marked by the K/Pg boundary, as well as its potential relation to this large biological crisis. For the first time, researchers examined whether this climate change coincides on the time scale with its potential causes: the Deccan massive volcanism (India) ─one of the most violent volcanic episodes in the geological history of the planet─ and the orbital variations of the Earth.

"The particularity of the Zumaia outcrops lies in that two types of sediments accumulated there ─some richer in clay and others richer in carbonate─ that we can now identify as strata or marl and limestone that alternate with each other to form rhythms", notes the researcher Sietske Batenburg, from the Department of Earth and Ocean Dynamics of the UB. "This strong rhythmicity in sedimentation is related to cyclical variations in the orientation and inclination of the Earth axis in the rotation movement, as well as in the translational movement around the Sun".

These astronomic configurations ─the known Milankovitch cycles, which repeat every 405,000, 100,000, 41,000 and 21,000 years─, regulate the amount of solar radiation they receive, modulate the global temperature of our planet and condition the type of sediment that reaches the oceans. "Thanks to these periodicities identified in the Zumaia sediments, we have been able to determine the most precise dating of the climatic episodes that took place around the time when the last dinosaurs lived", says PhD student Vicente Gilabert, from the Department of Earth Sciences at UZ, who will present his thesis defence by the end of this year.

Researchers present evidence that a cosmic impact destroyed a biblical city in the Jordan Valley
In the Middle Bronze Age (about 3,600 years ago or roughly 1650 BCE), the city of Tall el-Hammam was ascendant. Located on high ground in the southern Jordan Valley, northeast of the Dead Sea, the settlement in its time had become the largest continuously occupied Bronze Age city in the southern Levant, having hosted early civilization for a few thousand years. At that time, it was 10 times larger than Jerusalem and 5 times larger than Jericho.

"It's an incredibly culturally important area," said James Kennett (link is external), emeritus professor of earth science at UC Santa Barbara. "Much of where the early cultural complexity of humans developed is in this general area."

A favorite site for archaeologists and biblical scholars, the mound hosts evidence of culture all the way from the Chalcolithic, or Copper Age, all compacted into layers as the highly strategic settlement was built, destroyed and rebuilt over millennia.

But there is a 1.5-meter interval in the Middle Bronze Age II stratum that caught the interest of some researchers for its "highly unusual" materials. In addition to the debris one would expect from destruction via warfare and earthquakes, they found pottery shards with outer surfaces melted into glass, "bubbled" mudbrick and partially melted building material, all indications of an anomalously high-temperature event, much hotter than anything the technology of the time could produce.

"We saw evidence for temperatures greater than 2,000 degrees Celsius," said Kennett, whose research group at the time happened to have been building the case for an older cosmic airburst about 12,800 years ago that triggered major widespread burning, climatic changes and animal extinctions. The charred and melted materials at Tall el-Hammam looked familiar, and a group of researchers including impact scientist Allen West and Kennett joined Trinity Southwest University biblical scholar Philip J. Silvia's research effort to determine what happened at this city 3,650 years ago.

Their results (link is external) are published in the journal Nature Scientific Reports.

SOMETHING JUST HIT JUPITER

Last night, German astronomer Harald Paleske was watching the shadow of Io create a solar eclipse in the atmosphere of Jupiter when something unexpected happened. "A bright flash of light surprised me," he says. "It could only be an impact." Follow the arrows to the fireball. [see image above]

Reviewing his video frames, Paleske quickly ruled out objects such as airplanes and satellites, which might be crossing Jupiter at the time of his observation. The fireball was fixed in Jupiter's atmosphere. It first appeared at 22:39:27 UT on Sept. 13th and remained visible for a full two seconds. The most likely explanation is a small asteroid or comet striking the giant planet; an asteroid in the 100m size range would do the trick.

There are new discoveries to be made, even in the inner solar system. This was highlighted this past week with the announcement of the discovery of tiny asteroid 2021 PH27. The asteroid orbits the Sun in just 113 days, the shortest orbital period for any known asteroid and the second shortest orbital period for any object in the solar system next to the planet Mercury, at 88 days.

The discovery was made by astronomer Scott S. Sheppard (Carnegie Institution for Science) after searching through images taken by Ian Dell'Antonio and Shenming Fu (both Brown University) at evening twilight on August 13, 2021. Subsequent observations with multiple telescopes around the world enabled astronomers to confirm the asteroid's orbit.

The initial discovery observations were made using the Dark Energy Camera (DECam) based at the National Science Foundation's Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO) complex in Chile. Although the primary mission for the Dark Energy Camera is the study of cosmic expansion, the Brown University astronomers agreed to use DECam at the beginning of their observing run to take wide-field images in the fading twilight.

Researchers in the US have wound back the cosmic clock to determine that a spectacular comet whizzed past the Earth 5,000 years ago.

While the event isn't recorded in any historical account, the team were able to gather clues from more recently sighted comets.

In a paper published in the Astronomical Journal, they examined observations made by the Hubble Space Telescope of the comet ATLAS (C/2019 Y4), which Hubble watched break into pieces last year.

This comet is thought to be a fragment of a larger one that passed by the Earth in 1844, shining as brightly as Sirius, the brightest star in the sky.


By tracing the two comets' motions back through time, the researchers figured out that they are likely both parts of an even bigger one that last zipped through the inner Solar System 5,000 years ago, around the time that Ancient Egyptians were first settling into the Nile valley.

If the possibility of an asteroid called Bennu slamming into Earth a lifetime from now was keeping you up at night, NASA scientists think you can rest a little easier.

The agency's OSIRIS-REx spacecraft spent more than two years closely orbiting the space rock. And with that incredibly detailed view of the asteroid, experts studying potential space rock impacts with Earth have been able to fine-tune their existing models of Bennu's future.

As a result, scientists behind new research now say they're confident that the asteroid's total impact probability through 2300 is just 1 in 1,750. Estimates produced before OSIRIS-REx arrived at the space rock tallied the cumulative probability of a Bennu impact between the years 2175 and 2199 at 1 in 2,700, according to NASA. While a slightly higher risk than past estimates, it represents a minuscule change in an already minuscule risk, NASA said.

CBET xxxx & MPEC 2021-P05, issued on 2021, August 01, announce the discovery of a new comet (magnitude ~20) on CCD images taken on July 26.5 UT with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala. The new comet has been designated C/2021 O3 (PANSTARRS).

Stacking of 15 unfiltered exposures, 240 seconds each, obtained remotely on 2021, July 30.3 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 8" arcsecond in diameter (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

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

The pair, named 203 Pompeja and 269 Justitia, bear a resemblance to objects located in the outer solar system.

They're red, they're reasonably big, and they have no business being in the main asteroid belt, but their discovery confirms the complex conditions in place when the solar system was still forming.

New research published in the The Astrophysical Journal Letters details the discovery of two extremely red main-belt asteroids. Named 203 Pompeja and 269 Justitia, the asteroids have a redder spectral signature than any other asteroid in the main belt, that highly populated band of asteroids situated between the orbits of Mars and Jupiter. The new paper was led by Japan Aerospace Exploration Agency (JAXA) astronomer Sunao Hasegawa.

Importantly, these red asteroids resemble trans-Neptunian objects, that is, objects located farther away than Neptune, the most distant planet from the Sun (with no disrespect to dwarf planet Pluto). This could mean that 203 Pompeja and 269 Justitia formed way out there in the Kuiper Belt and then drifted inward when the solar system was still young. If confirmed, the new finding shows how chaotic the conditions were back then and that materials from different parts of the solar system would sometimes mix together.

The purpose of the study was to document the distribution and composition of large asteroids in the main belt. Large asteroids, especially those larger than 60 miles (100 km) in width, are likely survivors of the solar system's early days. By studying these objects, the scientists were hoping to catch a glimpse of what the conditions were like some 4 billion years ago.