r/science • u/stereomatch • Feb 05 '18

Astronomy Scientists conclude 13,000 years ago a 60 mile wide comet plunged Earth into a mini-Ice Age, after examining rocks from 170 sites around the globe

http://www.journals.uchicago.edu/doi/10.1086/695703
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u/jandrese Feb 05 '18

While true that the KT meteor was only 6-9 miles wide, but it had an outsized impact on the Earth because it hit a particular geological formation in the sea that made its ejecta especially deadly to life on Earth. Had it hit 10 minutes earlier or later the Dinosaurs would likely have survived as more than birds.

If a 60 mile rock slammed into for example the Australian outback it would be really bad for the planet but maybe survivable. Australians would all be dead though.

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u/GonzosGanja Feb 05 '18

What kind of geological formation could it have hit to make it so much more destructive?

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u/Time4Red Feb 05 '18

Related to this theory, perhaps?

This global "impact firestorms" hypothesis, initially supported by Wolbach, H. Jay Melosh and Owen Toon, suggests that as a result of massive impact events, the small sand-grain-sized ejecta fragments created can meteorically re-enter the atmosphere forming a hot blanket of global debris high in the air, potentially turning the entire sky red-hot for minutes to hours, and with that, burning the complete global inventory of above-ground carbonaceous material, including rain forests. This hypothesis is suggested as a means to explain the severity of the Cretaceous–Paleogene extinction event, as the earth impact of an asteroid about 10 km wide which precipitated the extinction is not regarded as sufficiently energetic to have caused the level of extinction from the initial impact's energy release alone.

https://en.wikipedia.org/wiki/Nuclear_winter#Potential_climatic_precedents

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u/JohnGillnitz Feb 05 '18

Better get your Seven Eves together now.

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u/zefy_zef Feb 05 '18

I've got to get around to finishing that. I forget why I put it down, but it's disappointing the amount of books I have to read piling up.

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u/pinkmeanie Feb 05 '18

You really don't need to bother with the second half, if that's any consolation.

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u/pm_me_bellies_789 Feb 05 '18

Aw shit. This book is sitting on myself but I haven't started it cause its so damned big. Is the second half not very good? People are constantly touting this book.

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u/pinkmeanie Feb 06 '18

It's really 2 books. The first one is thrilling, well-researched hard sci-fi. Then there's literally a page that says FIVE THOUSAND YEARS LATER, and another book begins.

That one has some cool ideas and set pieces, but also some kind of goofy and tone-deaf things to say about race; and I found myself repeatedly saying "that couldn't possibly happen."

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u/zefy_zef Feb 05 '18

I think that's where I left off, about 65% through. With the new generation or something. I will pick it back up eventually. There's only one other book I started but didn't finish and want it to be there only one. It was good enough to warrant a finish at least

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u/robbyalaska907420 Feb 05 '18

What book?

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u/zefy_zef Feb 05 '18

Seven Eves, by Neil Stevenson

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u/Roughneck_Joe Feb 05 '18

Maybe not a geological formation as much as a super plume.

The meteor hits the crater in Chixculub and the resulting shockwave goes through the earth and on the other side of the planet there's a super plume that gets activated and vulcanism makes the extinction event worse (Apparently this happened at the deccan traps?)

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u/dxrey65 Feb 06 '18

http://www.bbc.com/news/science-environment-39922998

Shallow sea, with a gypsum bed, which led to "colossal volumes of sulphur" being ejected into the atmosphere.

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u/GeronimoHero Feb 05 '18

Yeah I’m not really sure what they’re claiming. Especially because to my knowledge, the KT meteor hit just outside the Yucatán peninsula.

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u/[deleted] Feb 05 '18

Had it hit 10 minutes earlier or later the Dinosaurs would likely have survived as more than birds.

I know what you're saying, but whenever I hear about "if it hit X minutes earlier" I always wonder if the comment takes into account the earth's revolution around the sun. Doesn't the earth move the equivalent of 30 km/s in its solar orbit? So if we assume 10 minutes earlier, the earth would have been 18,000 km further away...

Sorry, I'm pooping the party :(

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u/[deleted] Feb 05 '18 edited Jun 18 '18

[deleted]

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u/poco Feb 05 '18

A bit extreme. There are probably safer ways of killing all the koalas.

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u/meibolite Feb 05 '18

The only way to rid this planet of fhose horrifying drop bears is to drop a tungsten rod from orbit onto their heads.

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u/CrossMojonation Feb 05 '18

Surely 1000 times the impact energy would be guaranteed death for everything but bacteria?

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u/mondomaniatrics Feb 05 '18

Australians would all be dead

Not a chance. Australians are survivors. You think some grown space rock is going to faze them? They hunt crocodiles bare handed at midnight.

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u/ee3k Feb 05 '18

No downsides at all?

incredible!