Simulation of 100km asteroid hitting Earth.

Found this in a bootnote on El Reg and thought it was pretty cool.

http://www.youtube.com/watch?v=3JHdYBet_4Q&eurl=http://www.sosyalmekan.com/blog/index.php

It looks like at the end, the earth is molten rock.. does it look that way to you?

Weird, cool, scary, all of the above.

An impact that size would generate a massive amount of energy into the planet, most of which would be absorbed by the mantle. The vast majority of that energy would be in the form of heat. If you heat up the mantle, it starts melting the rocks above it. Heat it enough, and it could melt all the way up through the crust. The roughly 1000km impactor in the video would be more than big enough to do the job.

FYI, there are many scientists who believe that this exact scenario happened several times in the early days of the Earth. After an impact like that, it would take millions of years for the Earths surface to cool enough to allow the oceans to re-establish themselves.

The heat that would cause the melting of the surface actually comes from the 6,000 degree cloud of rock vapor that envelopes the planet during the first 24 hours after such a hit. Based on the discussion of this kind of event in the program I mentioned in post #7, the heat would not penetrate that far into the surface in the year that it exists, and within a few thousand years, the planet would have cooled down enough for the oceans to reform.

I think in order to cause the level of destruction you mentioned, the impacting body would have to be MUCH larger - like the size of Mars (which by the way, is about the same size of the object whose impact is believed to have led to formation of the Moon.)

Still, unless you're an extremopile microbe buried deep underground, it would not be a fun experience to live through (or not, as would be the case.) :evilgrin:

the visual was interesting anyway, though.

The footage comes from a series named "Miracle Planet," which dealt with the evolution of life on this rock. If I remember correctly, this was a joint production of either The Science Channel or the BBC (can't remember which right now,) and one of the Japanese TV networks.

That footage was actually used twice in the program. This clip seems to have come from the final show in the program (which appropriately enough was titled "Life Invincible.") There was also a earlier show in the series - devoted to how the first microbes managed to survive an estimated FIVE impacts of this size - that went into more detail on the mechanics of these "sterilization events."

They re-broadcast this series every few months it seems, so it should be back on the air sometime in the near future.

I'll keep a look out for it.

A 100km impactor wouldn't cause much loss of oceans. such an impactor would boil off the top few hundred meters, but the deep oceans would in mostly insulated. the effects of such impacts on the early Earth is why it is thought life began in the deep ocean.

As it strikes the portion of atmosphere it shows is a small fraction of the asteroids diameter. Our significant atmosphere is about 100km deep. So I'd guess the video shows a strike by a 500-1,000km rock.

And yah, a rock that size would toast us. Depending on relative velocities I'd guess it could rip a chunk right out of us.

that would put it at 1000-2000 km. 100km is only 50 miles, or about the size of a large city, not the state of Texas... ;)

Hey if we've got to go...that's definately the way I would choose. I imagine it would be very pretty for a few seconds. :)

...are in big trouble in this scenario.

Don't ask me how, but Mothra seems to be able to fly in space. (Or am I remembering those movies incorrectly?)

She flies in space in Godzilla vs. Space Godzilla.

I just came across this secret government video that shows that in the unlikely event that an object this large ever set its sights on Earth, we have the perfect defense against it...:rofl: