# What happens when an asteriod hits the Earth? **URL:** \ **Category:** Factual Questions\ **Created:** [October 1, 2016, 11:53am UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349 "2016-10-01T11:53:45Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 2, 2016, 4:02pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/21 "2016-10-02T16:02:39Z")
True. As I said. My (not quite explicit) point was simply that here in 2016 we could probably save a nucleus of humanity in underground retreats if the mission required 5 years of food storage and then a return to the very different, but still readily habitable, surface. But we’d probably fail at doing the same thing if the scenario required them to be self-sufficient while completely isolated from the surface for, say, 200 years. IMO the hardest part is the social/political aspect. If the folks who go into the retreat are trained pros who expect to emerge while still of working age then the project almost certainly succeeds. OTOH, if their great grandkids will be the first generation to have even a glimmer of a hope of emerging the project is a lot more likely to go all _Lord of the Flies_ somewhere along the way. Or simply suffer mechanical / ecological breakdown. Doubly so when you consider that any _a priori_ estimate of when the surface will recover enough is necessarily an experiment with n=1 and huge error bars. Once they’ve retreated underground the survivor’s field of view of the outside world will rapidly contract to a soda straw. If by bad luck the surface at their location was desert-ified enough, they could be down there for centuries after much of the rest of the planet was, unbeknownst to them, a prolific greenhouse. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [October 2, 2016, 4:29pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/22 "2016-10-02T16:29:18Z")
Wouldn’t the water in the oceans protect some sea life from extinction? The History Channel presentation said Sea Turtles would stand a good chance at survival. Humans that lived near seas where these turtles lived could use them as a food source. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [October 2, 2016, 5:07pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/23 "2016-10-02T17:07:18Z")
I think it’s a mistake to imagine a catastrophe that kills 75% of all species in one day. Sure, lots and lots of plants and animals die on Day 1. But the real problem is the next year or two. Sure, plants die in the firestorms and tsunamis and possible antipodean flood basalts. But the real killer is atmospheric dust, which lowers global temperatures, which mean literal years without summers. Plant life dies back. Herbivores that survive the impact starve without plant food. Carnivores starve without animal food. The full ecological disaster takes decades to fully play out, as species that survived Day 1 and Year 1 go extinct due to massive ecological change that they can’t adapt to. The good news is that humans only need the 5 year bunkers that LSLguy talked about. If you’ve got stored seeds that can be planted 5 years later, temperatures should have returned to near normal. The problem isn’t surviving 5 years on stored food and then restarting agriculture. The problem is that there will be way too many human survivors on Day 2. It’s easy to stock up a bunkers with food for millions of people, but you’ll have hundreds of millions of survivors who will want that food, and they’re going to be very unhappy about being locked outside. So they storm the bunker, and instead of food for a million people for 5 years you have food for a hundred million people for a month. ---
**Author:** ![FlikTheBlue](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fliktheblue/32/10972_2.png) [@FlikTheBlue](https://boards.straightdope.com/u/FlikTheBlue)\ **Post date:** [October 2, 2016, 8:06pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/24 "2016-10-02T20:06:13Z")
It’s hard to believe an impact would be felt immediately and worldwide. Let’s say the Chicxulub event happened today. I’m sure I would go very quickly since I live in South Texas. But what about someone living in the Himalayas, or the people at Uluru is Australia. Wouldn’t those people have a good chance of surviving the initial impact? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 2, 2016, 8:14pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/25 "2016-10-02T20:14:16Z")
> [@](#): > > Quoth **Musicat** : > > Awesome video, but doesn’t seem to take into account the massive gravitational effects this would have. And since the Space Station isn’t entirely outside the atmosphere, the orbit wouldn’t last long, either. You’re never _entirely_ outside of the atmosphere, and how high is “close enough” depends on why you’re asking. The ISS is already high enough that it can go for years without orbital boosting, and the Moon has far greater sectional density than the ISS, so the effects of atmosphere would be much smaller. Plus, that’s just for the nearest portions of the Moon (I assume that “the height of the ISS” just means the nearest surface), and most of the Moon would be considerably higher up yet. > [@](#): > > As far as the implied question “How likely is it for us to look up in the 21st Century and say, ‘It’s a bird! It’s a plane! It’s an asteroid! {splat}’?”, not very likely for very large objects. One would hope so, but we don’t have nearly as many resources devoted to skywatching as we should. There have been a number of close calls with potentially-catastrophic asteroids that we’ve discovered only after they were on their way back out again. EDIT: Folks in the Himalayas would probably be just as much toast as you are in Texas (just on a somewhat longer time scale), but the Australians might have a decent chance, and New Zealanders even more so. The key isn’t so much distance, as which side of the Equator you’re on: Weather systems (and the dust and debris they’d be carrying) have a very difficult time crossing the Equator, due to Coriolis effects, so there’d be much less dust in the opposite hemisphere. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 2, 2016, 8:17pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/26 "2016-10-02T20:17:38Z")
> [@FlikTheBlue](#): > > It’s hard to believe an impact would be felt immediately and worldwide. Let’s say the Chicxulub event happened today. I’m sure I would go very quickly since I live in South Texas. But what about someone living in the Himalayas, or the people at Uluru is Australia. Wouldn’t those people have a good chance of surviving the initial impact? Massive amounts of crap will be raining down from the sky all around the planet within a couple hours. Assuming a water impact the tsunami will be across even the largest ocean in less than 12 hours. About 3/4ths of humanity lives close enough to a seashore to be at risk from a kilometer scale tsunami. Certainly a big number of people will be alive on Day 2. But also a lot of people will be dead or dying on Day 2. Then the Mad Max survivalist / prepper stuff gets underway late on Day 2. Mass (sub-)urban unrest / migration begins on Day 3 when folks realize the grocery stores aren’t going to be restocked. Ever. it’s gonna be a really crappy week to be a Earther. Regardless of your location or species. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 2, 2016, 8:28pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/27 "2016-10-02T20:28:59Z")
> [@FlikTheBlue](#): > > It’s hard to believe an impact would be felt immediately and worldwide. Let’s say the Chicxulub event happened today. I’m sure I would go very quickly since I live in South Texas. But what about someone living in the Himalayas, or the people at Uluru is Australia. Wouldn’t those people have a good chance of surviving the initial impact? Do you count the literal rain of fire afterwards as part of the initial impact? There’s a layer of carbon from the impact pretty much everywhere on earth. The entire world burned. Also, the folks in Australia are close to the antipodal point, where all of the shock waves from the impact converge. They are going to face severe earthquakes and possibly some nasty volcanic activity as well. All of this won’t be seconds from the impact, but it will all be on day 1. That said, humans are good at finding creative ways to survive, so as a species they’d have a relatively high survival rate from the initial impact and would fare better than most animals with respect to surviving the artificial winter that follows. Food is going to become mighty scarce, though. Imagine that all of the food crops in the entire world burned, and you had to wait for surviving sprouts to spring out of the ashes before you could eat. It wasn’t just a big kaboom on one side of the world. The effects were global, and devastating. Keep in mind, the fact that 75 percent of species were wiped out doesn’t mean than 75 percent of the life on earth was wiped out and 25 percent remained. We’re talking species, not raw numbers. If 95 percent of a species got wiped out but the 5 percent that remained were able to thrive, then that species was on the 25 percent survival list. In raw numbers, much more than 75 percent of life was wiped out, probably well up into the high 90s, percentage-wise. 25 percent of those species managed to recover from that massive dying. 75 percent didn’t. Also, most of the big survivors were in the water. Crocodiles were about the biggest thing that survived on land, and they survived because they can go under water for prolonge periods of time to avoid the flames, and they can go a long time in between meals and not starve to death. That’s a good indication of what you’d need to survive the impact event. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [October 2, 2016, 9:08pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/28 "2016-10-02T21:08:21Z")
A simulator, from Purdue Uni & Imperial College London. [https://www.purdue.edu/impactearth/](https://www.purdue.edu/impactearth/) ---
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [October 2, 2016, 10:18pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/29 "2016-10-02T22:18:57Z")
> [@engineer\_comp\_geek](#): > > …most of the big survivors were in the water… Speaking of that – the world’s operational nuclear submarine fleet is probably over 100 boats, with an average crew size of about 140 each. So right now there is a theoretical capability to have 14,000 people on vessels that can survive 1,000 feet underwater for a year, provided they were provisioned with food. If there was even 24 hr advance notice of an asteroid calamity, it stands to reason that provisioning these and getting any docked ones to sea would be a high priority. I wonder if anyone has modeled the asteroid survivability of a widely dispersed, deeply submerged submarine fleet? ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [October 2, 2016, 10:47pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/30 "2016-10-02T22:47:50Z")
Maybe that is why they are allowing women on board the subs now. ---
**Author:** ![DagNation](https://avatars.discourse-cdn.com/v4/letter/d/ee7513/32.png) [@DagNation](https://boards.straightdope.com/u/DagNation)\ **Post date:** [October 3, 2016, 1:03am UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/31 "2016-10-03T01:03:55Z")
Regarding timing of after affecs: The first ejecta from the impact would hit the antipode about 45 minutes after impact (the shortest path would be a ballistic trajectory that reaches up to a couple of hundred KM above the surface, and an object in a round orbit at that height takes 90 minutes per orbit. Anything moving faster will not land so soon). The first seismic waves would be around 16 hours for the straight through the core wave, and around 24 hours for surface waves. I have no idea how much, if any, energy goes straight through the core. This assumes a propagation of around 500 MPH, around the speed of sound in those materials. From what I understand, the impact came near the end of the volcanic period, even though the idea that the impact caused the volcanism does sound good. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 3, 2016, 1:05am UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/32 "2016-10-03T01:05:27Z")
> [@Mangosteen](#): > > Maybe that is why they are allowing women on board the subs now. If so, ref Dr. Strangelove they seem to have the male/female ration reversed vs the optimal one. Then again, the Navy is still learning. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [October 3, 2016, 10:42am UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/33 "2016-10-03T10:42:49Z")
I, for one, will welcome our new mustelid overlords. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 3, 2016, 1:31pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/34 "2016-10-03T13:31:31Z")
> [@](#): > > Quoth **DagNation** : > > From what I understand, the impact came near the end of the volcanic period, even though the idea that the impact caused the volcanism does sound good. Probably, but the error bars are large enough that it’s still possible that the impact caused the volcanism. That’s why I said “some speculation”, rather than a stronger phrasing. ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [October 3, 2016, 2:40pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/35 "2016-10-03T14:40:26Z")
> [@joema](#): > > Speaking of that – the world’s operational nuclear submarine fleet is probably over 100 boats, with an average crew size of about 140 each. So right now there is a theoretical capability to have 14,000 people on vessels that can survive 1,000 feet underwater for a year, provided they were provisioned with food. I wonder about the shock wave. Water is nearly incompressible, and that would be a heck of a bang. I’m picturing them flattening like a stepped-on empty beer can as the shock wave hits. Likely? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 3, 2016, 2:51pm UTC](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349/36 "2016-10-03T14:51:43Z")
Inverse square law still applies. Net of refraction and therefore constructive and destructive interference in spots. Far enough out you’ll be looking at tsunami propagation which is harmless to subs. For sure there’s a radius within which the sub (it’s debris more accurately) will be knocked into Earth orbit. A bit further out it’ll be just be suborbital. As you suggest there’s going to be a big area of ocean where the sub will be can-crushed. Beyond that damaged severely. And eventually beyond that just the crew being deafened or banged around inside. Subs in a different ocean will probably hear some amazing noises on sonar if the sonar isn’t overloaded by the low frequency component. Given some numbers we could run some calcs. [Previous page](https://boards.straightdope.com/t/what-happens-when-an-asteriod-hits-the-earth/767349.md?page=1)