Strange Skies
S


Attention

Airbursts: An underappreciated hazard

Airburst
© astronomynow.com
A paper published in March of 2021 in the journal Science Advances reports on the discovery of evidence for a large airburst type impact within the SØr Rondane Mountains, Queen Maud Land, East Antarctica. The report bears the names of a 15-member international team that did the research. The lead author was M. Van Ginneken with the Belgian Geological Survey. In the first sentence of the abstract to the article the authors support something I have been saying for literally decades: "Large airbursts, the most frequent hazardous impact events, are estimated to occur orders of magnitude more frequently than crater-forming impacts."

This fact is confirmed simply because airbursts don't leave impact craters. In this case the fingerprints of the event took the form of condensation spherules resulting from "a touchdown event, in which a projectile vapor jet interacts with the Antarctic ice sheet." The authors go on to explain that "Finding evidence of these low-altitude meteoritic events thus remains critical to understanding the impact history of Earth and estimating hazardous effects of asteroid impacts." They further report that "In recent years, meteoritic ablation debris resulting from airburst events have been found in three different locations of Antarctica. The material . . . all appears to have been produced during a Tunguska-like airburst event 480 thousand years (ka) ago."

With respect to their research, they say: "Here, we present the discovery of extraterrestrial particles formed during a significantly larger event recovered on . . . Queen Maud Land, East Antarctica. The characteristic features of the recovered particles attest to an unusual type of touchdown event, intermediate between an airburst and a crater-forming impact, during which the high-velocity vapor jet produced by the total disruption of an asteroid reached the Antarctic ice sheet." This event was estimated by the team to have occurred about 430 thousand years ago.

The authors provide some critical perspective on the effects of these type of impacts:

"The impact hazards resulting form the atmospheric entry of an asteroid that are currently being addressed by impact mitigation programs depend mainly on whether the impactor reaches the ground or is entirely disrupted in the atmosphere (i.e., airburst). For small-to medium-sized impactors (50- to 150-m diameter) producing airbursts, the main hazard is limited to blast effects resulting in strong overpressures over areas of up to 100,000 km2 wide. [38,600 sq miles] Thermal radiation may also result in fires over an area of 10 to 1000 km2 wide. . . . in addition to shockwaves and thermal radiation covering the aforementioned areas, these events are potentially destructive over a large area, corresponding to the area of interaction between the hot jet and the ground. The authors point out that such an event over Antarctica would inject ice crystals and impact dust into the upper atmosphere but would not directly affect human activity. However, they explain that "if a touchdown impact event takes place above a densely populated area, this would result in millions of casualties and severe damages over distances of up to hundreds of kilometers."

Now comes a new report in Earth and Planetary Science Letters on the discovery of evidence for yet another airburst event over Antarctica. The 11-member team responsible for the report is comprised of geologists, astrophysicists, and archaeologists from the U.S., the United Kingdom, Belgium, Russia, Japan, France and Italy.

Comet 2

The 'Devil Comet' is now a naked eye object

Suddenly, amateur astronomers are seeing a naked-eye comet in the evening sky. It's Comet 12P/Pons-Brooks, also known as the 'devil comet'. Waiting for next Monday's solar eclipse in Mexico, Petr Horálek photographed the comet last night and found it much brighter than the last time he saw it:

Devil Comet
© Petr Horálek/Institute of Physics in OpavaTaken by Petr Horálek/Institute of Physics in Opava on April 4, 2024 @ Veľká Lomnica, Slovakia; Monterrey, Mexico
"I assume an outburst is in progress," says Horálek. "My estimate of the comet's magnitude is +3.5. Definitely worth taking a look in the next hours and days."

Indeed, now is a good time to look. After sunset, the comet emerges in the western sky not far from the planet Jupiter. Naked-eye observers will see a dim fuzzball. Cameras and small telescopes reveal the comet's magnificent tail.

Nebula

Northern lights shine over erupting volcano in Iceland

mmmmmm
Timelapse video has shown a volcano in the Icelandic town of Grindavik erupting against the backdrop of the Northern Lights.

The volcano there is continuing to erupt - but to a lesser extent than it did in January and February when it sent lava rushing towards Grindavik.

The Icelandic Met Office says it is possible that the deep magma supply and the lava outflow might have found a balance where it continues to erupt but with reduced power.

Grindavik's population of about 3,800 people were evacuated in November following a series of earthquakes that opened large cracks in the earth between the town and Sýlingarfell, a small mountain to the north and it was evacuated again in January the night before the latest eruption started.


Bizarro Earth

The Polar Vortex is spinning backwards

Earlier this month, atmospheric scientists noticed something unusual in the Arctic stratosphere. The polar vortex was spinning backward.

"The vortex changed direction around March 4th," reports Dr. Amy Butler, author of NOAA's Polar Vortex Blog. "It was a substantial reversal, reaching -20.5 m/s a few days ago, which puts it in the top 6 strongest such events since 1979."
Polar Vortex
© NOAA Climate Gov Data: Waugh et al 2017
Two weeks later, it is still spinning backwards. What's going on?

"Atmospheric planetary waves have been breaking in the polar stratosphere, increasing its temperature," says Butler. "We call this a 'Sudden Stratospheric Warming' event, and it can cause the vortex to change direction.'"

In recent years, many people have heard the phrase "polar vortex" because of the effect it can have on winter weather. When the polar vortex is strong and stable, it helps confine cold air to polar regions. When the vortex weakens or becomes disturbed, cold air spills out to lower latitudes.

Solar Flares

Northern lights deliver spectacular show over Russia (PHOTOS)

Northern lights in St. Petersburg and Leningrad Region.
© RIA Novosti via TelegramNorthern lights in St. Petersburg and Leningrad Region.

The incredible display was seen in regions as far south as Moscow

Stunning images of the aurora borealis, also known as the northern lights, were captured in the skies above multiple Russian cities on Sunday.

People from the northern regions of Leningrad, Tver, Pskov, and Novgorod, as well as the cities of Volokolamsk and Murmansk, shared breathtaking photographs of the natural phenomenon. The impressive light show, which is caused by solar storms, began at around 8pm and lasted until midnight.


Comment:
In the last few days, many other locations have witnessed northern lights. On the same evening as the photos from Russia, there were other areas, that witnessed spectacular shows:




Attention

Large ingenous events, cosmic impacts and crises in the history of life

Impact
© Randall Carlson Newsletter - March 2024
Last month, in the February 2024 issue of the Kosmographia Newsletter I reported on new research correlating a series of large-scale igneous events which produced the Central Atlantic Magmatic Province (CAMP) and the Siberian Traps with mass extinction episodes. On February 8 another paper was published in the journal Global and Planetary Change which further supports correlations between mass extinction episodes with gigantic volcanic eruptions and catastrophic cosmic impacts. The lead author of the paper is Michael Rampino, who has for decades been in the forefront of researching catastrophic events in Earth history. I have been following his work since the early 1980s and hold him in high regard as a scientist who is willing to think outside established paradigms of Earth history. The abstract to the paper begins:

"We find that Large Igneous Province (LIP) volcanism, mostly continental flood basalts (CFBs), along with the largest extraterrestrial impacts show significant correlations with mass-extinction events in the Phanerozoic geologic record. The ages of the 6 major marine mass extinctions (≥ 40% extinction of genera) of the last 541 MY ̶ the end-Ordovician (~444 Ma), late Devonian (~ 372 Ma), end-Guadalupian (~259 Ma), end-Permian (~ 252 Ma), end-Triassic (~201 Ma), and end-Cretaceous (66 Ma) extinctions are significantly correlated with high-quality U — Pb zircon and 40Ar/39Ar ages of 6 continental flood basalts (CFBs) ̶ the Cape St. Mary's, Viluy, Emeishan, Siberian, CAMP, and the Deccan Basalts.

U — Pb zircon dating (Uranium-lead) is a widely used method for dating metamorphic rocks typically employing a thermal ionization mass spectrometer. Zircon is used because it includes uranium and thorium atoms in its crystalline structure when forming but rejects lead, so any lead found in a zircon crystal is radiogenic, meaning it results from radioactive decay. Argon dating can measure Argon isotopes from a single mineral grain. The ratio of Argon 40 to Argon 39 yields the age of the sample.

The extinctions listed above are considered to be major events in the history of life on Earth. A number of less severe extinctions have taken place, although these events are somewhat more difficult to discern in the geologic/palaeontologic record. Nevertheless, a correlation can be discerned between these extinctions and both volcanic eruptions and cosmic impact.

Info

Weird dent in Earth's magnetic field is messing with auroras in the Southern Hemisphere

The South Atlantic Anomaly makes a section of the southern aurora weaker and likely dimmer.
Aurora Southern
© Skyimages via Getty ImagesAurora seen above Queenstown, New Zealand. Researchers have discovered a huge dent in Earth's magnetic field weakens the southern lights.
A bizarre dent in Earth's magnetic field above the southern Atlantic Ocean weakens the southern lights, new research finds.

The South Atlantic Anomaly is a large, oval-shaped region over South America and the southern Atlantic Ocean where Earth's magnetic field is weakest. The anomaly is already well known for allowing charged particles from the sun to dip close to Earth's surface, exposing satellites orbiting above to high levels of ionizing radiation, according to NASA.

Now, a study published Feb. 8 in the journal Geophysical Research Letters finds that this weak region also affects the southern aurora, the glowing lights in the upper atmosphere that can be seen at high latitudes. The southern lights occur over and around Antarctica and are the equivalent of the northern lights that dance over the Arctic and Subarctic.

Auroras are caused by solar particles interacting with gas molecules in Earth's atmosphere and are usually considered largely under the control of the sun, said Zhi-Yang Liu, first author of the study and a researcher at the Institute of Space Physics and Applied Technology at Peking University in China. But the new research highlights the two-way nature of the relationship, Liu told Live Science in an email.

Galaxy

A nova in the making: Will T Coronae Borealis pop in 2024?

A recurrent nova in action.
© NASAA recurrent nova in action.
If predictions are correct, a key outburst star could put on a show in early 2024.

If astronomers are correct, a familiar northern constellation could briefly take on a different appearance in 2024, as a nova once again blazes into prominence. The star in question is T Coronae Borealis, also referred to as the 'Blaze Star' or T CrB. Located in the corner of the constellation Corona Borealis or the Northern Crown, T CrB is generally at a quiescent +10th magnitude, barely discernible with binoculars... but once every 60 years, the star has flared briefly into naked eye visibility at around +2nd magnitude.
Finding T CrB in the sky.

Info

3 new moons discovered around Uranus and Neptune

The International Astronomical Union has confirmed the existence of three currently unnamed moons — one around Uranus and two orbiting Neptune.
New Moons
© Getty ImagesNeptune (right) and Uranus (bottom left) have both gained at least one extra moon.
The solar system just got three new official residents — a trio of tiny moons, one of which orbits Uranus and two more that circle Neptune.

The three moons were all spotted several years ago but were recently confirmed by the International Astronomical Union's (IAU) Minor Planet Center — the organization responsible for naming new solar system objects such as moons, asteroids and comets. The new trio, which have been given numerical designations, will be given formal, literature and mythology-inspired names in the coming years.

Uranus' new moon, S/2023 U1, is only around 5 miles (8 kilometers) across, making it one of the smallest known moons around any of the eight planets in the solar system, alongside Mars' minute companion Deimos. The diminutive moon, which takes around 680 days to orbit around Uranus, brings the planet's total moon count to 28. Like the other Uranian moons, S/2023 U1 will eventually be named after a character from the plays of William Shakespeare, joining the likes of previously discovered moons such as Titania, Oberon and Puck.

Neptune's new satellites, S/2002 N5 and S/2021 N1, are around 14.3 miles (23 km) and 8.7 miles (14 km) wide respectively. S/2021 N1 takes around 9 years to orbit Neptune, while S/2002 N5 takes almost 27 years to orbit the furthest planet from the sun, which now has 16 known moons. Like other Neptunian moons, the newly recognized bodies will be named after the Nereids — the daughters of the sea god Nereus from Greek mythology.

The new moons were each spotted using ground-based telescopes, which is no mean feat considering their diminutive size and distance from our planet.

Nebula

Webb finds evidence for neutron star at heart of young supernova remnant

SN 1987A.
© NASA, ESA, CSA, STScI, Claes Fransson (Stockholm University), Mikako Matsuura (Cardiff University), M. Barlow (UCL), Patrick Kavanagh (Maynooth University), Josefin Larsson (KTH)The James Webb Space Telescope has observed the best evidence yet for emission from a neutron star at the site of a well-known and recently-observed supernova known as SN 1987A. At left is a NIRCam (Near-Infrared Camera) image released in 2023. The image at top right shows light from singly ionized argon (Argon II) captured by the Medium Resolution Spectrograph (MRS) mode of MIRI (Mid-Infrared Instrument). The image at bottom right shows light from multiply ionized argon captured by the NIRSpec (Near-Infrared Spectrograph). Both instruments show a strong signal from the center of the supernova remnant. This indicated to the science team that there is a source of high-energy radiation there, most likely a neutron star.
Astronomers detect long-sought compact object within the remnant of Supernova 1987A.

In February 1987, the closest supernova to earth in almost 400 years exploded onto the scene. Designated Supernova 1987A (SN 1987A), it resulted from the death of a massive star in the Large Magellanic Cloud, a dwarf galaxy 160,000 light-years away. In the decades since, its remnant has been studied by telescopes at all wavelengths of light from X-rays to radio. Yet despite all the scrutiny, one mystery has remained.

Theory predicted that the stellar explosion should have produced either a neutron star or a black hole. Evidence for such a compact object has long been sought, without success. Now, new observations by NASA's James Webb Space Telescope have provided the first direct evidence of what is likely a neutron star, revealed by the effects of its high-energy emission.