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In death of dinosaurs, it was all about the asteroid—not volcanoes – Phys.org

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Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers. It was all about the asteroid.

In a break from a number of other recent studies, Yale assistant professor of geology & geophysics Pincelli Hull and her colleagues argue in a new research paper in Science that environmental impacts from in India in the region known as the Deccan Traps happened well before the Cretaceous-Paleogene event 66 million years ago and therefore did not contribute to the .

Most scientists acknowledge that the , also known as K-Pg, occurred after an asteroid slammed into Earth. Some researchers also have focused on the role of volcanoes in K-Pg due to indications that happened around the same time.

“Volcanoes can drive mass extinctions because they release lots of gases, like SO2 and CO2, that can alter the climate and acidify the world,” said Hull, lead author of the new study. “But recent work has focused on the timing of lava eruption rather than gas release.”

To pinpoint the timing of volcanic gas emission, Hull and her colleagues compared and the (an isotope is an atom with a higher or lower number of neutrons than normal) from marine fossils with models of the climatic effect of CO2 release. They concluded that most of the gas release happened well before the asteroid impact—and that the asteroid was the sole driver of extinction.

“Volcanic activity in the late Cretaceous caused a gradual global warming event of about two degrees, but not mass extinction,” said former Yale researcher Michael Henehan, who compiled the temperature records for the study. “A number of species moved toward the North and South poles but moved back well before the asteroid impact.”

Added Hull, “A lot of people have speculated that volcanoes mattered to K-Pg, and we’re saying, ‘No, they didn’t.'”

Recent work on the Deccan Traps, in India, has also pointed to massive eruptions in the immediate aftermath of the K-Pg mass extinction. These results have puzzled scientists because there is no warming event to match. The new study suggests an answer to this puzzle, as well.

“The K-Pg extinction was a mass extinction and this profoundly altered the global carbon cycle,” said Yale postdoctoral associate Donald Penman, the study’s modeler. “Our results show that these changes would allow the ocean to absorb an enormous amount of CO2 on long time scales—perhaps hiding the warming effects of volcanism in the aftermath of the event.”


Explore further

Fossilized seashells show signs of ocean acidification before dinosaur-annihilating asteroid


More information:
P.M. Hull el al., “On impact and volcanism across the Cretaceous-Paleogene boundary,” Science (2019). science.sciencemag.org/cgi/doi … 1126/science.aay5055

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In death of dinosaurs, it was all about the asteroid—not volcanoes (2020, January 16)
retrieved 17 January 2020
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Bright-Red "Blood Snow" Is Falling From the Sky in Antarctica – Futurism

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Blood Snow

A Facebook post by Ukraine’s Ministry of Education and Science shows a research station on an island just off the coast of Antarctica’s northernmost peninsula covered in “blood snow.”

The gory-looking scene is not the result of a seal hunt gone wrong — it’s an astonishingly red-pigmented, microscopic algae called Chlamydomonas nivalis, which thrives in freezing water as the ice melts during Antarctica’s record-breaking warm summer.

Algae Bloom

When summer hits the polar regions, the algae bloom, staining the snow and ice around it in blood-resembling red, as Live Science explains. The phenomenon was first noticed by Aristotle thousands of years ago and is often referred to as “watermelon snow” thanks to its subtly sweet scent and color.

What makes the blooming algae red is the same stuff that give carrots and watermelons their reddish tint — carotenoids.

Feedback Loop

It’s a stunning display of a natural phenomenon — but it also creates a nasty feedback loop that causes the ice to melt faster. The red color causes less sunlight to be reflected off the snow, causing it to melt faster, as the Ukrainian team explains in its post. The accelerated melting then causes more algae to grow, completing the cycle.

It’s not the only surreal display in the world caused by such a feedback loop, as Live Science points out. Blooming algae caused sea foam to swallow up the coast of a Spanish town in January. Similar algae blooms even caused shores around islands in the East China Sea to glow blue.

READ MORE: Spooky ‘blood snow’ invades Antarctic island [Live Science]

More on algae: A New Bioreactor Captures as Much Carbon as an Acre of Trees

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Scientists detect biggest explosion since Big Bang – BBC News

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Scientists have detected evidence for a colossal explosion in space – five times bigger than anything observed before.

The huge release of energy is thought to have emanated from a supermassive black hole some 390 million light years from Earth.

The eruption is said to have left a giant dent in the Ophiuchus galaxy cluster.

Researchers reported their findings in The Astrophysical Journal.

They had long thought there was something strange about Ophiuchus galaxy cluster, which is a giant aggregation containing thousands of individual galaxies intermingled with hot gas and dark matter. X-ray telescopes had spied a curious curved edge to it.

The speculation was that this might be the wall of a cavity that had been sculpted in its gas by emissions from a central black hole.

Black holes are famous for gorging on infalling matter, but they will also expel prodigious amounts of material and energy in the form of jets.

Scientists at first doubted their explanation however, because the cavity was so big; you could fit 15 of our own Milky Way galaxies in a row into the hole.

And that meant any black hole explosion would have to have been unimaginably prodigious.

But new telescope data from the Murchison Widefield Array (MWA) in Australia and the Giant Metrewave Radio Telescope (GMRT) in India seem to confirm it.

“In some ways, this blast is similar to how the eruption of Mount St Helens (volcano) in 1980 ripped off the top of the mountain,” said Simona Giacintucci of the Naval Research Laboratory in Washington, DC, and lead author of the study.

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Astronomers have discovered the biggest explosion seen in the universe – CBC.ca

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Astronomers have discovered the biggest explosion seen in the universe, originating from a super-massive black hole.

Scientists reported Thursday that the blast came from a black hole in a cluster of galaxies 390 million light-years away.

The explosion was so large it carved out a crater in the hot gas that could hold 15 Milky Ways, said lead author Simona Giacintucci of the Naval Research Laboratory in Washington.

It’s five times bigger than the previous record holder.

Astronomers used NASA’s Chandra X-Ray Observatory to make the discovery, along with a European space observatory and ground telescopes. They believe the explosion came from the heart of the Ophiuchus cluster of thousands of galaxies: a large galaxy at the centre contains a colossal black hole.

First hint of explosion came 4 years ago

Black holes don’t just draw matter in. They also blast out jets of material and energy.

The first hint of this giant explosion actually came in 2016. Chandra images of the Ophiuchus galaxy cluster revealed an unusual curved edge, but scientists ruled out an eruption given the amount of energy that would have been needed to carve out such a large cavity in the gas.

The two space observatories, along with radio data from telescopes in Australia and India, confirmed that the curvature was, indeed, part of a cavity.

“The radio data fit inside the X-rays like a hand in a glove,” co-author Maxim Markevitch, of NASA’s Goddard Space Flight Center in Maryland, said in a statement. “This is the clincher that tells us an eruption of unprecedented size occurred here.”

The blast is believed to be over by now: There are no signs of jets currently shooting from the black hole.

More observations are needed in other wavelengths to better understand what occurred, according to the team.

The findings appeared in the Astrophysical Journal.

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