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Mon, 19 Feb 2018
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Comets


Fireball

The Big Burn - Global fire 13k years ago

YDB Event
© UC Santa Barbara
Black dots represent locations of 129 lake cores exhibiting charcoal records and purple dots represent marine sites with charcoal and/or soot spanning the Younger Dryas onset.
Some 13,000 years ago, a cataclysmic event occurred on Earth that was likely responsible for the collapse of the Clovis people and the extinction of megafauna such as mammoths and mastodons.

That juncture in the planet's geologic history - marked by a distinct layer called the Younger Dryas Boundary - features many anomalies that support the theory of a cometary cloud impacting Earth. The collision triggered a massive biomass burning event, and the resulting soot, ash and dust in the global atmosphere blocked out the sun, which prevented photosynthesis - a phenomenon called impact winter.

For more than a decade, UC Santa Barbara professor emeritus James Kennett has studied elements found at the Younger Dryas Boundary (YDB). He has collaborated with scientists around the globe, providing evidence at the YDB for a platinum peak as well as for spherules, melt glass, nanodiamonds and other exotic materials that can be explained only by cosmic impact.

Kennett and his colleagues have now published new research in the Journal of Geology. In two papers, they analyze existing published scientific data from ice, glacier, lake, marine and terrestrial sediment cores, finding evidence for an extensive biomass burning episode at the YDB layer representing one of the most extreme events - if not the most extreme - ever experienced by our own species, anatomically modern humans. Recent extreme climate and burn events like those in California pale by comparison, Kennett said.

Comment: 12,800 years ago: Cosmic impact produced global fires larger than dinosaur killer event - Research


Fireball

NASA - 2 new 'potentially hazardous' asteroids careening towards Earth

Asteroids
© YouTube/NASA
Two previously unknown "potentially hazardous" asteroids will pass close to Earth this week, and once again we're reminded that a) NASA's ability to spot potentially cataclysmic near-Earth asteroids is currently limited to a few days' warning, and b) the area around Earth is swarming with dozens of giant space rocks, which are apparently stealthy enough to remain undetected until it's too late. Not an encouraging combination, especially after the two near-misses last month (YD7 and 2018 AJ).


Comment: It is a sobering thought but There is NO WAY TO TELL what might hit, and when. The world's observatories were focused on 2012 DA14 when, 6 hours before its scheduled fly-by, another large rock - from another direction - arrived out of nowhere to explode over Chelyabinsk, Russia!


The new asteroids are named 2018 CC and 2018 CB, and are between 9 and 38 meters in size. For comparison, a standard X-Wing is about 12.5 meters long, while the Space Shuttle is about 56 meters.

NASA deems any asteroid that comes within closer than 4.6 million miles of Earth to be "potentially hazardous." This might not sound close in terrestrial terminology but in terms of space distance, it's close enough to worry.

Comment: The skies have been noticeably active recently with an alarming number of space rocks:


Comet 2

Early humans witnessed global cooling, warming, and massive fires from comet debris impacts says major study

global temperatures 20,000 years

Graph of temperature for the last 20,000 years, provided to illustrate this story, but was not part of the original press release.
New research suggests toward end of Ice Age, human beings witnessed fires larger than dinosaur killers

On a ho-hum day some 12,800 years ago, the Earth had emerged from another ice age. Things were warming up, and the glaciers had retreated.

Out of nowhere, the sky was lit with fireballs. This was followed by shock waves.

Fires rushed across the landscape, and dust clogged the sky, cutting off the sunlight. As the climate rapidly cooled, plants died, food sources were snuffed out, and the glaciers advanced again. Ocean currents shifted, setting the climate into a colder, almost "ice age" state that lasted an additional thousand years.

Comment: For more on the events surrounding the Younger Dryas Impact and the very real possibility of it occurring again, see:


Fireball

Fireball spotted over Peru (VIDEO)

Fireball
© YouTube
Here at Outer Places, we pride ourselves in being both believers and skeptics in equal proportion.

When Peruvian residents saw a giant fireball careening through the sky before crashing in southeastern Peru earlier this week, they were understandably shaken. And though the Peruvian air force has since explained the event as the remains of a satellite, they were understandably skeptical.

What makes this more than your standard, cut and dry gap between civilian and government knowledge? The fact that we've seen personal footage of the fireball, too. A gentleman sent us in a video of the fireball, captured on his cell phone, that shows the object moving in inexplicable ways, far different than any falling object moves as it plummets to the ground. It's easy to understand why some are already racing to claim this is genuine evidence of an alien spacecraft.


Comment: We've seen a few video angles of this event. There wasn't anything unusual about its trajectory or rate of falling.


Meteorologist Alejandro Fonesca, from the Universidade Federal do Acre, confirmed that there were no meteorites scheduled to fall in the area, and thinks that the fireball was either an old satellite or other human-made space litter.


Comment: Meteorites are never 'scheduled' to fall. Meteor showers happen like clockwork, though there's variability with those too. Meteorites are the result of large meteors exploding/disintegrating in the upper atmosphere, and they're not usually part of the 'scheduled' showers.


Fireball

'Meteor' car commercial at the right time!

Meteor Commercial
© YouTube Screen shot
This commercial, which came out about a week and a half ago, has plenty to laugh about.

The joke, of course, is that this sucker is so roomy you can fit more than what you'd first grab fleeing your home if, says, a meteor was about to strike.

The secondary joke is that Americans have become so materialistic that they'd go back for seconds and thirds if they felt they could.

What makes it funniest, though, is it must have turned a few heads given the way a giant fireball streaked across the Michigan sky last week.

Fireball

Incoming: Massive house-sized asteroid will fly close to Earth next week

Asteroid
© YouTube
Unlike that false alarm in Hawaii, this potentially cataclysmic piece of news is real: an asteroid between 22 and 68 meters in diameter is going to swing past Earth on January 23 at around 12,300 miles an hour (around Mach 16). It's going to come within 1.1 million miles of Earth, but it's unclear whether its trajectory will cause it to hit Earth or fly past harmlessly.

The asteroid, named 2018 AJ, is just one of several asteroids that have suddenly popped up on NASA's radar without warning-the last one was 2017 YD7, which was spotted December 28 and flew past Earth on January 3.

The scary thing about these rocks is that once we spotted them, there's very little we can do to stop them: according to NASA's Planetary Defense Coordination Office, we'd need a few decades of advance warning to deal with an asteroid 100 meters in size or larger. From there, a couple options open up, including knocking the asteroid off course with a "kinetic impactor" or using a "gravity tractor" to change its trajectory.

Comet 2

Dynamic space: Rotation of Comet 41P makes inexplicably slows down

Comet 41P
© Chris Schur/Schurs Astrophotography
Comet 41P/Tuttle-Giacobini-Kresák glides beneath the galaxy NGC 3198 on March 14, 2017, two weeks before the object's closest approach to Earth.
National Harbor, Md. - A small comet broke a rotation-speed record in a big way: New work reveals that an icy rock known as 41P dramatically slowed its spin at an unprecedented rate in 2017, spinning down at about 10 times the pace of the next-ranked comet.

This comet, whose full name is 41P/Tuttle-Giacobini-Kresák, experienced "the largest but also the fastest change that has ever been seen in a comet rotation," said Dennis Bodewits, an associate research scientist at the University of Maryland (UMD) in College Park.

Bodewits presented his team's findings Wednesday (Jan. 10) during a press conference held here at the 231st meeting of the American Astronomical Society.

Comment: What could have acted on it? It need not have been something it came close to. And they used to say space was 'stable'...


Info

Large ancient impact event discovered in Southeast Asia

Impact on Earth
© John R. Foster/Science Source
An artist’s representation of a large impact on Earth.
A kilometer-size asteroid slammed into Earth about 800,000 years ago with so much force that it scattered debris across a 10th of our planet's surface. Yet its impact crater remains undiscovered. Now, glassy remains believed to have come from the strike suggest the asteroid hit southeast Asia as our close ancestors walked the Earth.

"This impact event is the youngest of this size during human evolution with likely worldwide effects," says Mario Trieloff, a geochemist at the University of Heidelberg in Germany not involved in the research. Large impacts can disrupt Earth's climate by spewing dirt and soot high into the atmosphere, where it can block sunlight for months or even years.

Putative remains from this impact have been found before. Researchers have recovered chunks of glassy debris known as tektites across Asia, Australia, and Antarctica, and their distribution pattern suggests the asteroid struck Southeast Asia: The largest tektites-weighing more than 20 kilograms and presumably ejected the shortest distances from the impact-have been found there.

Comet 2

Did comet impacts kill lots of animals in Alaska?

impact-related microspherules
© Hagstrum et. al/Scientific Reports
To laypeople, the "muck" found in certain areas of Alaska and Yukon is just dirt - dark, silty, often frozen, and full of plant material. To miners, it is somewhat of a nuisance. When dug out and left to thaw, the muck lets loose a fetid stench due to its high organic content. To scientists, however, the muck is a graveyard, and a fascinating one at that. Over the years, thousands of remains of bison, mammoth, horse, musk ox, moose, lynx, lion, mastodon, bear, caribou, and even camel have been uncovered.

More interesting than the mere presence of this zoological gold mine is the actual condition of the remains. Cached inside the frozen mucks for as long as 48,000 years, the remains are remarkably well preserved, with some carcasses mostly intact and effectively mummified. Even more curious, many animals show no signs of predation, scavenging, or decomposition, and despite disarticulated bones, seemed to be in relatively good health at the time of their demise.

This made Jonathan Hagstrum, a research geophysicist at the U.S. Geological Survey, wonder... What killed all of these animals? He and colleagues Richard Firestone, Allen West, James Weaver, and Ted Bunch share an intriguing hypothesis.

They think the seemingly sudden deaths of many of these animals in the Alaskan and Yukon mucks could be explained by airbursts and impacts from comet debris that struck Earth during the Late Pleistocene, between 11,000 and 46,000 years ago. Hagstrum and his colleagues recently presented new evidence for this idea in the journal Scientific Reports.

Fireball

Meteor fireball explodes over Crimea

Meteorite
© an-crimea.ru
A powerful explosion occurred in the sky over the city of Simferopol, the Crimea, on December 26. The origin of the explosion remains unknown; EMERCOM officials are trying to look into circumstances.

Local residents have posted a few photos taken in first minutes after the explosion. The photos depict a white trail in the sky, which usually remains behind a flying plane, but it is not straight.

Some people assumed that the explosion could be related to fighter aircraft and their aerobatic stunts.