# A doomsday scenario : What sort of asteroid will destroy just half of the world? **URL:** \ **Category:** Factual Questions\ **Created:** [November 24, 2008, 4:17pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257 "2008-11-24T16:17:56Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Crowbar\_of\_Irony\_3](https://avatars.discourse-cdn.com/v4/letter/c/f08c70/32.png) [@Crowbar\_of\_Irony\_3](https://boards.straightdope.com/u/Crowbar_of_Irony_3)\ **Post date:** [November 24, 2008, 4:17pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/1 "2008-11-24T16:17:56Z")
From my understanding, if a large-enough asteroid hits the Earth’s ocean, the world will be destroyed. But is it possible for only a quarter or half of the known world to be destroyed by a smaller asteroid? What would be the crash scenario like? ---
**Author:** ![Morgenstern](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@Morgenstern](https://boards.straightdope.com/u/Morgenstern)\ **Post date:** [November 24, 2008, 4:23pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/2 "2008-11-24T16:23:52Z")
Do you mean kill half of all life or destroy half of the planet? ---
**Author:** ![Crowbar\_of\_Irony\_3](https://avatars.discourse-cdn.com/v4/letter/c/f08c70/32.png) [@Crowbar\_of\_Irony\_3](https://boards.straightdope.com/u/Crowbar_of_Irony_3)\ **Post date:** [November 24, 2008, 4:44pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/3 "2008-11-24T16:44:15Z")
> [@Morgenstern](#): > > Do you mean kill half of all life or destroy half of the planet? Sorry, here’s the clarification: half of life. Or just affect half of the planet and have the other half still sustaining life. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [November 24, 2008, 4:53pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/4 "2008-11-24T16:53:45Z")
All the five major extinctions in earth history are thought to have been caused by an asteroid impact, although other factors may have contributed. In each case, a large fraction - up to 90% - of life was driven to extinction. In each case some life survived. See [Extinction event](http://en.wikipedia.org/wiki/Extinction_event). A ten-mile diameter comet or asteroid would suffice. ---
**Author:** ![VunderBob](https://avatars.discourse-cdn.com/v4/letter/v/839c29/32.png) [@VunderBob](https://boards.straightdope.com/u/VunderBob)\ **Post date:** [November 24, 2008, 4:53pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/5 "2008-11-24T16:53:51Z")
An meteorite that kills half of all life on impact will probably take out the rest of life too, in the aftermath. Famine, climate changes, etc. A small one, leaving a crater like the one in Arizona, could take out a lot of life from the ripples, and still leave something behind to carry on. Modern civilization would be toast… ---
**Author:** ![runcible\_spoon](https://avatars.discourse-cdn.com/v4/letter/r/9fc29f/32.png) [@runcible\_spoon](https://boards.straightdope.com/u/runcible_spoon)\ **Post date:** [November 24, 2008, 6:06pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/6 "2008-11-24T18:06:21Z")
Yeah, the problem is that a lot of the destruction has to do with throwing dust into the atmosphere. There’s a certain area that’s just going to get wiped out, but for the rest of the planet, you’re going to get some death all over the place. With the right size and speed you could probably kill half the entities on the planet, but you wouldn’t get a screwed-half and a fine-half of the planet. Of course, you also have to address what is meant by ‘half of life’ - are we talking individuals? Species? ‘Able to support life’ is a tough standard, because there’s probably gonna be some bacteria everywhere. Able to support humans, now - that might be specific enough to work with. But between size, speed, and impact location, I don’t think it would be possible to predict accurately. ---
**Author:** ![Crowbar\_of\_Irony\_3](https://avatars.discourse-cdn.com/v4/letter/c/f08c70/32.png) [@Crowbar\_of\_Irony\_3](https://boards.straightdope.com/u/Crowbar_of_Irony_3)\ **Post date:** [November 24, 2008, 6:23pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/7 "2008-11-24T18:23:30Z")
> [@runcible\_spoon](#): > > Able to support humans, now - that might be specific enough to work with. But between size, speed, and impact location, I don’t think it would be possible to predict accurately. Yep, I have human life in my mind. My bad. ---
**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:** [November 24, 2008, 6:38pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/8 "2008-11-24T18:38:48Z")
> [@](#): > > With the right size and speed you could probably kill half the entities on the planet, but you wouldn’t get a screwed-half and a fine-half of the planet. Actually, in some scenarios, you can. If the primary cause of death is something in the atmosphere (such as suspended dust blocking sunlight), then the hemisphere the object hit in (northern or southern) would be affected much worse than the other one, since it’s very difficult for winds to cross the equator, and therefore for contaminants to mix between the hemispheres. And we’re well past the point where a dino-killer asteroid could completely wipe out humanity: We’ve been too technologically advanced for that for millenia. It’d certainly kill plenty of people, but there’d be enough folks with the few years of food stockpiles needed to wait it out. ---
**Author:** ![\_Undecided\_Adrian](https://avatars.discourse-cdn.com/v4/letter/_/eada6e/32.png) [@\_Undecided\_Adrian](https://boards.straightdope.com/u/_Undecided_Adrian)\ **Post date:** [November 24, 2008, 6:57pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/9 "2008-11-24T18:57:41Z")
There is an event which could destroy exactly half the earth (initially): a sufficiently close [gamma ray burst](http://en.wikipedia.org/wiki/Gamma_ray_burst#Mass_extinction_on_Earth). Inside of a couple of seconds one hemisphere would be thoroughly irradiated and maybe even stripped of the athmosphere. Of course the other half would be in for a world of hurt as a consequence, so it doesn’t fit your question perfectly. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [November 24, 2008, 7:01pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/10 "2008-11-24T19:01:33Z")
> [@Chronos](#): > > It’d certainly kill plenty of people, but there’d be enough folks with the few years of food stockpiles needed to wait it out. Most of those would probably be Mormons. ---
**Author:** ![Projammer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/projammer/32/559_2.png) [@Projammer](https://boards.straightdope.com/u/Projammer)\ **Post date:** [November 24, 2008, 7:56pm UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/11 "2008-11-24T19:56:22Z")
As mentioned before, the problem with smacking the earth with a rock is that it’s going to throw up a lot of dust, making it a global event as far as atmospheric changes. Probably a better approach would be to pelt one side with many small meteors in a shotgun effect. You’d still get some dust cloud, but you’d be better able to ‘shape’ the destruction. ---
**Author:** ![brossa](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/brossa/32/3040_2.png) [@brossa](https://boards.straightdope.com/u/brossa)\ **Post date:** [November 25, 2008, 2:46am UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/12 "2008-11-25T02:46:12Z")
You could have an icy body come in from outside the solar system from the north or south which breaks up into a bunch of fragments, each of which does an air-burst-type detonation similar to the Tunguska event. If you fake it a bit you can stitch a line of detonations northish-southish from Canada to Argentina or vice versa. Much of the New World is destroyed by firestorms and blast damage, and many die in the immediate aftermath. The smoke from all the fires, although bad, wouldn’t be as bad as a bunch of solid ground-impactors. ---
**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:** [November 25, 2008, 6:11am UTC](https://boards.straightdope.com/t/a-doomsday-scenario-what-sort-of-asteroid-will-destroy-just-half-of-the-world/474257/13 "2008-11-25T06:11:40Z")
> [@](#): > > Most of those would probably be Mormons. Or the first people to get to the grocery store to loot it, or farmers with full silos, or people who saw the asteroid coming and prepared, or folks who just happen to see the pragmatic value in large food stores.