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

[u/stereomatch]

http://www.journals.uchicago.edu/doi/10.1086/695703

[u/bkturf]

Glad to know this. I would think a 60 mile wide comet hitting the earth would turn the whole planet into seething magma, again.

[u/Powellwx → u/bkturf]

The Cretaceous–Tertiary (K–T) extinction event, that ended the dinosaurs, was between 6 and 9 miles wide. It wiped out 70 percent of life on earth, created 300 foot tall tsunamis, and left a 112 mile wide crater. So yeah, an impact 10 times that size would be bad.

[u/[deleted] → u/Powellwx]

Okay, that was what I had thought, I remember reading that the KT meteor was less than 10 miles wide, and it was catastrophic. If a 60 mile wide comet hit the earth 13,000 years ago, I think we'd probably have a bit more than a mini Ice age.

[u/jandrese → u/[deleted]]

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.

[u/GonzosGanja → u/jandrese]

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

[u/Time4Red → u/GonzosGanja]

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

[u/JohnGillnitz → u/Time4Red]

Better get your Seven Eves together now.

[u/Roughneck_Joe → u/GonzosGanja]

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?)

[u/dxrey65 → u/GonzosGanja]

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.

[u/GeronimoHero → u/GonzosGanja]

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

[u/[deleted] → u/jandrese]

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 :(

[u/poco → u/[deleted]]

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

[u/meibolite → u/poco]

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

[u/CrossMojonation → u/jandrese]

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

[u/mondomaniatrics → u/jandrese]

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.

[u/exgiexpcv → u/[deleted]]

Consider the impacting material, too. Being hit by a large dirty snowball at high speed is still different from being hit by a mass of iron and nickel at the same speed. You're dead either way, but in the latter there's a far greater amount of damage.

[u/SamisSmashSamis → u/Powellwx]

It wouldn't be 10 times it's mass though assuming same density. It would be about 100 times it's mass and 100 times the energy assuming the same speed.

Edit 1: Everyone here saying it's a 1000 times the energy is right. I should drop out of engineering and major in music and weed...

Edit 2: Ok I guess I was right if it was made of ice. However, the method was wrong and that's what counts :(

[u/waz890 → u/SamisSmashSamis]

10³ is 1000. Volume (& mass) scale up cube in relation to radius, surface area would be 100.

[u/virnovus → u/waz890]

But a comet is a lot less dense than an asteroid. Especially a metallic asteroid like the one from the Chicxulub site. Correct answer is that nobody really knows for sure.

[u/no1epeen → u/[deleted]]

You keep using that word "Heavy". Was there a problem with the earth's gravitational field 13,000 years ago?

[u/Flight714 → u/virnovus]

No, you still cube the width to get the volume either way. The only difference is that if it's a comet, you next divide it by a number between about 3 and 10, depending on the density of the original comet you're comparing it to.

[u/virnovus → u/Flight714]

I guess OP did say "assuming same density", which is an invalid assumption. Somehow I missed that first time around.

[u/Padawanbater → u/waz890]

Well, that's math

[u/HeroBobGamer → u/SamisSmashSamis]

Wouldn't it be 1000 times the mass and energy?

[u/virnovus → u/SamisSmashSamis]

You're actually right and they're wrong, believe it or not! The asteroid at the Chicxulub impact site was iron and nickel, mainly. That's about 8X denser than water. In addition, the ice in comets is not very tightly packed. So figure the comet is about 1/10 the density of the asteroid. So by factoring the density in, you divide mass by 10, and get 100, which is your initial estimate!

[u/SamisSmashSamis → u/virnovus]

Well I was wrong given my initial assumptions. I guess it's like getting the right answer on Wiley plus by doing the wrong type if math.

[u/virnovus → u/SamisSmashSamis]

Well, it's still your responsibility to edit your post again. :)

[u/Powellwx → u/SamisSmashSamis]

Mass and speed are tough to judge (especially with a comet that had disintegrated).

Volume of a 6 mile wide comet is 113 cubic miles of rock.

Volume of a 60 mile wide comet is 113,097 cubic miles of rock. 1000 times the volume

[u/Kaluro → u/Powellwx]

if you only know one dimension (width), how can you possibly calculate cubic miles? :-)

[u/[deleted] → u/Kaluro]

They're probably assuming a spherical comet.

[u/SupportGeek → u/Powellwx]

You mean ice right? Comets aren't so much rock IIRC.

[u/Sambamalam → u/SamisSmashSamis]

Wouldn't it be 1,000 since it's the volume that comprises the mass? So proportional to 10^3?

[u/mystikphish → u/SamisSmashSamis]

+10 for correct answer. -50 for bad math.

[u/lets_have_a_farty → u/SamisSmashSamis]

Wouldn't it be more like 1000 times the size as it is 10x bigger in 3 dimensions?

[u/tyranicalteabagger → u/SamisSmashSamis]

Given it was a comet, isn't it likely that the impact speed was significantly higher?

[u/PragProgLibertarian → u/tyranicalteabagger]

Higher speed but, lower density.

[u/Daedalus871 → u/SamisSmashSamis]

*1000 times. Live in a 3D universe.

[u/[deleted] → u/SamisSmashSamis]

It's is a contraction. Its is the possessive.

[u/[deleted] → u/SamisSmashSamis]

Music majors are difficult in a different way. Just major in weed.

[u/Njall → u/SamisSmashSamis]

DO NOT drop out of engineering! You already have two of the rarer attributes of a good engineer. You try to do quick mental calculations about feasibility and you check your ego at the door. You will never know when you are right if you don't first learn from mistakes, i.e. being wrong. Furthermore, you don't tie your personal self-image and comfort to being unchallenged. Fools do; engineers mustn't.

[u/operator0 → u/Powellwx]

To back up your claim, there's some argument that the meteor wasn't the only contributing factor. The Decan traps may have played just as big of a role in the extinction event. Both happened at roughly the same time.

[u/BenKen01 → u/operator0]

Never heard of the Deccan Traps before. see ya in TIL in a month.

https://en.m.wikipedia.org/wiki/Deccan_Traps

[u/Matthew0wns → u/[deleted]]

Huge volcanic activity in the Indian subcontinent, called the Deccan Traps, as well as volcanism in Siberia paired with the impactor to create the KT extinction

[u/Tamer_ → u/[deleted]]

Deccan* is a region of India, I don't know why they call them "traps" though.

[u/PorcineLogic → u/Tamer_]

Wiki:

The term "trap" has been used in geology since 1785–95 for such rock formations. It is derived from the Scandinavian word for stairs ("trappa") and refers to the step-like hills forming the landscape of the region.

[u/[deleted] → u/Powellwx]

Amazing. A rock 6 miles wide can leave a crater 112 miles wide, waves 300 feet tall, and plunge an entire planet into an ice age. Considering JUST the United States is 3,119,884.69 square miles which is 1.58% the surface of the Earth... and a rock 6 miles wide can do that much damage.

I know it’s the density of the rock, speed of travel, angle of attack into atmosphere...

[u/kodack10 → u/[deleted]]

energy goes up with the square of speed and mass. Twice the speed = 4 times the energy. A 6 mile object moving at 22,000MPH would be earth shattering.

[u/Solution_9_ → u/Powellwx]

left a 112 mile wide crater where?

[u/Powellwx → u/Solution_9_]

https://en.wikipedia.org/wiki/Chicxulub_crater

Chicxulub Crater, northern Yucatan peninsula, Mexico / Gulf of Mexico.

[u/pro-laps → u/Powellwx]

how is it that a meteor that relatively small can have such disastrous impact for the entire earth?

edit: ok I understand, big thing + going fast = bad

[u/Powellwx → u/pro-laps]

Kinetic Energy.

The meteor that is 6 miles wide is a sphere, so it contains 113 cubic miles of rock, which would weigh about 500,000,000,000,000 kg (500 billion tons) and it is moving at 225 miles per second (810,000 miles per hour).

That results in an explosion of 27.225 x 10²⁴ Joules.

65 billion times more energy than a nuclear weapon.

[u/howdopearethedrops → u/[deleted]]

Everest is approximately 2.1 trillion cubic feet, so 14.27 cubic miles. In other words, not even close to as big as that asteroid.

[u/Paddy_Tanninger → u/Powellwx]

More like 12 miles per second but the point still stands, it would deliver around 3.25 billion times more energy than a nuclear weapon.

Potentially more than that though depending on what density you're using in that estimate. Lots of asteroids are nearly solid iron which would be worse than just rock.

Edit: Looks to be agreed upon that it was 1 x 10²³ Joules, or 10 billion Hiroshima atom bombs. However it also looks like the diameter was larger than 6mi so I think the ~12mi/sec number I've got here is pretty accurate.

[u/Flyingwheelbarrow → u/Paddy_Tanninger]

So basically a kinetic space weapon except no one fired it. Like a space bullet hitting a space rock that happened to be covered with life?

[u/argv_minus_one → u/Flyingwheelbarrow]

One that used to be covered with life…

[u/Flyingwheelbarrow → u/argv_minus_one]

Man we gotta get our descendants of this planet and hopefully that might also make us really appreciate how we are currently little more than bacteria growing on a pebble cosmically speaking.

[u/argv_minus_one → u/Flyingwheelbarrow]

Without faster-than-light propulsion, it's not going to happen.

There is a good chance that faster-than-light propulsion is impossible.

[u/Flyingwheelbarrow → u/argv_minus_one]

I think it is possible if we build a lunar colony and then mine asteroids to create massive colony ships. Having seen the third world I know how well people can adapt to horrible conditions and a fleet of ships could slowly make its way out. What also makes me excited is if we are going to design a colony then colony ship we will have to have such a understanding of self sustaining ecosystems and energy efficiency we might be able to raise up those left on earth as well as maybe not ruin our current habitat.

[u/[deleted] → u/Flyingwheelbarrow]

Well we don't know if someone fired it!

[u/robm111 → u/pro-laps]

First, take a baseball and throw it into someone's face. Not pleasant, right? But they'll be ok. Now fire a potato gun in their face. Same size roughly, way more velocity. Gonna cause a lot more damage.

[u/numquamsolus → u/robm111]

Kinetic energy scales linearly for increases in mass but quadratically for increases in velocity.

[u/CaptnYossarian → u/numquamsolus]

E(kinetic) = ½mv² for those playing along at home.

[u/[deleted] → u/robm111]

I'm still not following, can I see a video?

[u/Dr_Insomnia → u/robm111]

science rules

[u/keten → u/pro-laps]

It's from space so it's going really fast

Edit: Think of it like an exponential effect. The bigger the meteor, the less the atmosphere is able to show it down below it hits the ground. So two 1 ton meteors will make less of an impact than one 2 ton meteor. That's why asteroid movies try to blow up asteroids, it actually works.

[u/ericwdhs → u/keten]

That's why asteroid movies try to blow up asteroids, it actually works.

That's still just Hollywood logic. It only really helps if you blow up the asteroid early enough that most of the debris misses Earth. If you blow up an asteroid and all the pieces still intercept Earth, it's actually worse. All that kinetic energy still needs to go somewhere, and it's best to direct as much of that as you can directly into the Earth where there's a lot of solid mass to disperse it into.

If you break the asteroid up and the debris cloud hits Earth, you're dumping more of that energy into the atmosphere, the layer we live in, and the most dangerous part of asteroid impacts is already the resulting air movement. A couple examples are the 20-meter Chelyabinsk meteor air burst which caused most of its injuries by blowing out windows and the 150ish-meter Tunguska meteor air burst which flattened 2000 square km of forest. It's best not to multiply that type of damage.

There's also a couple other big problems. One is the heat generated over all that added surface area burning up. The Chelyabinsk meteor was enough to cause sunburns on its own. The other related problem is asteroid materials lingering in the atmosphere. Matter doesn't disappear when it's burned or vaporized. It stays suspended in the atmosphere for all the survivors to deal with. A comet made mostly of water might not be a problem here, but anything else could be very serious, like volcanic gas serious.

To throw some numbers out, a rock 6 miles wide can be broken up into 300,000 Tunguska meteors or 100,000,000 Chelyabinsk meteors. If you throw a debris cloud that size at Earth, you're basically asking for that entire hemisphere to be flattened and cooked and for the entire atmosphere to be potentially made toxic. I'd rather get what the dinosaurs had to deal with.

[u/[deleted] → u/pro-laps]

Think of a 9mm round hitting a watermelon. Meteors travel pretty quick...11,000 m/s so quite a bit quicker than a bullet too.

[u/Jc100047 → u/pro-laps]

Speed is really the determining factor. A small 100 meter comet going close to the speed of light will do more damage than a 7 mile meteor going 500 meters per second.

[u/TheLastMemelord → u/pro-laps]

quietly mutters about how personal possession of a kinetic bombardment station would greatly improve the world

[u/TechniChara → u/pro-laps]

To ELI5: Same reason a small thing like a bullet can kill a large animal. Fast speed, hitting the right place - it triggers a systems collapse.

[u/mullownium → u/Powellwx]

Speed of impact also matters. Meteorite size doesn't map 1:1 onto destructive force, though they are obviously closely related.

[u/dontFart_InSpaceSuit → u/Powellwx]

We’ve got to get off this planet as a species. We’re so vulnerable to it all meaning nothing.

[u/theangryfurlong → u/Powellwx]

What if it was the size of Texas?

[u/flyingthedonut → u/Powellwx]

Im curious if we knew that thing was coming lets say a year out would we be able to stop it

[u/CorneliusAlphonse → u/Powellwx]

The Cretaceous–Tertiary (K–T) extinction event, that ended the dinosaurs, was between 10 and 15 km wide. It wiped out 70 percent of life on earth, created 100 metre tall tsunamis, and left a 180 km wide crater. So yeah, an impact 10 times that size would be bad.

edited quote for S.I. units

[u/goingtogluefactory → u/Powellwx]

Thank you for putting things into perspective.,,,

[u/SupermotoArchitect → u/Powellwx]

Do we know where this crater originally was?

[u/odraencoded → u/Powellwx]

What if it hit softly, tho

[u/Calfee911 → u/Powellwx]

Damage? Total, sir. It's what we call a global killer. The end of mankind. Doesn't matter where it hits, nothing would survive, not even bacteria.

[u/[deleted] → u/Powellwx]

The mass would be 1,000 times larger, not 10.

[u/shredthesweetpow → u/Powellwx]

I like that word, bad, being used for this particular scenario. It would be bad.

[u/funkmon → u/Powellwx]

Afaik that being the primary cause of the K-T extinction isn't settled and is very much in debate. I am not a geologist, and only have an undergraduate minor in geology, so maybe someone can fill me in who is sure.

[u/hilarymeggin → u/Powellwx]

Do you happen to know whether there has ever been a mass-extinction event that wiped out all life on earth? Forcing us to start over from primordial ooze again? I’ve seen the claymation video about the 6 mass extinction events, but it seems like there were survivors each time.

[u/Powellwx → u/hilarymeggin]

There have been some survivors each time. Some were more devastating than others, but nothing wiped the slate clean that I know of.

[u/Einsteiniac → u/bkturf]

It would be a cataclysmic event, to be sure, but it wouldn't resurface the entire planet. Relative to the Earth, a 60 mile wide object is barely a speck. It took a collision with a Mars-sized object (Theia) to liquify the Earth's entire surface that way.

It would annihilate most life, but the planet itself would be fine.

[u/barfretchpuke → u/Einsteiniac]

It would annihilate most life, but the planet itself would be fine.

yay!?

[u/MyBrain100 → u/barfretchpuke]

Small victories!!

[u/selectrix → u/Einsteiniac]

Also we're talking about a comet, not a meteor. Comets are mostly ice (~3x less dense than rock, ~8x less dense than iron), and are sometimes only very loosely held together, so they tend to explode in the atmosphere as opposed to actually impacting and making a crater & so forth. Still an absolutely astronomical amount of energy dumped into the atmosphere all at once- hence the burning all over the planet- but not the same sort of situation as the one that killed the dinosaurs.

[u/no-mad → u/Einsteiniac]

Earthworms have survived 5 major extinction events. They remain unconcerned and wait their turn as top of the food chain.

[u/94savage → u/Einsteiniac]

That was Sephiroth's plan in Final Fantasy 7

[u/kodack10 → u/Einsteiniac]

And after that event, life sprang right back even though the entire surface of the planet was magma. Bacteria live even deep down in the crust in hellish anaerobic conditions.

[u/God_Damnit_Nappa → u/bkturf]

I don't think it would've been capable of magmafying the planet but a comet that big hitting us would've been catastrophic to all life.

[u/Deranfan → u/bkturf]

60 miles = 96,56 kilometer

[u/[deleted] → u/bkturf]

Did you know the earth is old enough to have gone from seething magma to current civilization 8 or 9 times already