Watch this CG footage from the Discovery Channel, depicting a 500 km-wide asteroid striking the Earth. Note how it peels away the Earth’s crust like you might dig the skin off an apple with your fingernail.
If you don’t watch until the end, here’s the punchline. That’s happened at least six times in Earth’s history. Fingers crossed, eh?
DarrenBarefoot.com 
Yes, thank you. Very cheery.
Haha, hopefully the asteroid will come after human activity has reduced the earth to nothing!
Hmm. I know it’s Discovery Channel n all, but I kind of find that a little hard to believe. Mostly because if *all* life had been vaporized six times, how would we be here?
Nice musical choice though.
I have seen this video before, but without the overlay captions, which I think are from a slightly misinformed (and a bit typo-prone) third party. While it’s true that significant impacts have occurred numerous times in the past four billion years or so, they were not as catastrophic as the one portrayed in the video, because the objects were much smaller.
The video is supposed to be a 500 km-diameter asteroid, and would probably have wiped out life entirely — so we wouldn’t be here. The only comparable event I know of was the Mars-size object that probably collided with a proto-Earth and created the Moon, but that was probably before we even had a proper atmosphere, let alone any life.
Most estimates of the Cretaceous-Tertiary impact that helped kill off the dinosaurs 65 million years ago (the most recent major extinction-causing hit) propose an object about 10 km across, for instance. That wasn’t the largest such event — the Permian extinction about 245 million years ago might have killed 96% of all species, but it’s not clear whether an impact was a cause. If it were, that would still have been a smaller object than in the video.
So while such an impact could happen, saying that six like it did isn’t quite accurate. Also, objects that large in the solar system are big enough that we might actually be aware of them substantially in advance. Whether we could do anything is another question; impacts by smaller but still substantial objects would probably still kill all the people and large mammals on the planet anyway.
How soon would we be aware of such a threat? And what evacuation measures are currently being prepared? 😉
It’s extraordinarily unlikely (as far as I understand it) that an object as large as 500 km across wouldn’t already be in a relatively stable orbit within the solar system; one on a collision course with Earth would probably be detectable decades in advance, if we were looking properly (and I’m not sure we are).
However, we might easily miss much smaller objects capable of making humans extinct, even until the very moment they arrive. Even if we do spot them, we have no plans in place to do anything about it. There are theoretical ways any of these objects might be nudged off collision course with enough advance warning, but we have no way to do that if we spotted one right now.
But while one could arrive anytime, even on average we probably have another few tens of millions of years before the next one shows up. A short time in geological terms, but awhile for us.
I always appreciate context for our tenuous existence on planet Earth but why-oh-way did they feel necessary to further dramatize the animation by adding Pink Floyd music?
As that classic rock overplay droned on I found myself rooting for the asteroid.
Kinda makes you wish you were a cockroach. 😀
Oh, great. Now what am I supposed to do?