Who Will Dig Our Bones if Apophis Hits?

Apophis Symbol (Stargate).

Image via Wikipedia

Something that could very well make us all subjects of an archaeological dig is an asteroid impact. The very fate of the dinosaurs, which once ruled our planet up to about 65 Ma might some day be our own. If you haven’t seen it, I recommend Phil Plait’s Bad Universe, which, in its first episode, took a look at killer asteroids and the various ways we might deflect or prevent a potential extinction-level impact.

If you’re interested in modeling asteroid impacts, you can play around with an online simulation at Purdue University. You can input your own data: size of asteroid, composition, velocity, angle of approach, what sort of surface it impacts, etc. I chose Apophis, not so much because I have a particular fear of this one over any other, but because Apophis was the bad guy in Stargate SG-1. Love that show. Incidentally -and quite trivially- the archaeologist, Daniel Jackson, was played by actor Michael Shanks. Coincidentally, there is also a prominent archaeologist with the name Michael Shanks. Did I mention I’m a fan of Stargate?

In the simulation I ran of Apophis (the asteroid, not the Goa’uld), the Earth didn’t fare so well. Particularly the Eastern United States. A crater about 3.5 km in diameter and over 1 km deep was created 500 km from Dallas, TX somewhere towards northeastern Canada or Maine. Ejecta in the form of a fine dusting with occasional large fragments reached Dallas only 5.57 minutes after the impact.

Screenshot of Impact Earth!

Luckily, neither the Earth’s axis was not tilted and the orbit was not shifted to any noticeable degree. But the impact had the energy of 1,660 megatons of TNT. The average interval between impacts of this magnitude somewhere on Earth is somewhere around 50,000 years. The fireball, at over 500 km away, is well enough below the horizon that Dallas doesn’t suffer any ill effects, but we do get an air blast that arrives 25.3 minutes after impact, raising the wind velocity to about 6.21 mph and the blast can be heard to a level about as loud as heavy traffic. Long before that, however, somewhere around a minute and a half after the impact, an earthquake at 6.6 on the Richter Scale is felt 500 km away, but feeling like a passing truck hitting a pothole in the road nearby.

I suspect if I run the simulation again at 20 km instead of 500 km, the damage estimates would be different. I did. They were. People and buildings catching fire from the thermal radiation; a few people and buildings getting knocked down by the seismic effects; more people getting knocked down by the airblast; etc.

It ain’t pretty, but Apophis wouldn’t be an extinction-level event according to the simulation and the parameters I put in. Go check it out. Have fun. Destroy the world!

Another bit of Stargate trivia: in the show, another bad guy (Anubis) set an asteroid into motion that would collide with Earth. Luckily for us, the show’s heroes were able to put it in hyperspace for a few seconds to let it pass Earth up. I didn’t see Phil Plait try that method on his show!

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