Satellite Collisions COULD KILL US ALL!

We've all heard about the satellite wreck, the other day. Well, Dr. Phil Plait, the Bad Astronomer and President of the JREF, did some math. And failed. So he did some MOAR math and was full of win- deadly, megaton, kilo-rifle-shot, win:

Remember, I’m trying to be very rough here; I don’t care if I’m off in my numbers by a factor or two or not; I just want an approximation.

The kinetic energy of an object is equal to 1/2 x its mass x its velocity^2. Again, because I’m being really rough here, it doesn’t matter which satellite hits the other. We can assume they have about the same mass, so the kinetic energy (in ergs, which I’ll explain in a second) is

KE = 0.5 x 700,000 grams x (800,000 cm/sec)^2 =
2 x 10^17 ergs

An erg is a small unit of energy, but 200,000,000,000,000,000 is a lot of them. Blowing up a ton of TNT releases about 4 x 10^16 ergs, so this collision was roughly the equivalent of lobbing 5 tons of TNT at the satellites.

but that's not all...

Read More...*

That’s why there’s a large cloud of expanding debris; each piece of shattered satellite carried away a piece of that violent energy release. The energy of collision changed the orbits of all those shards, so they are now orbiting the Earth on new paths that take them higher or lower over the surface, right into the traffic lanes of other satellites.

So eventually, some may once again find an object in their way. And because of the high velocity, the kinetic energy of impact even from a low-mass piece can be pretty fierce. A rifle bullet does a huge amount of damage when it hits something, and it has a mass of about 10 grams and moves at a paltry 1 km/sec. Now think of the damage inflicted by a small satellite chunk that masses about 1 kg (100 times as much as the bullet) and moving 8 times faster… the energy of impact is 6400 times that of the bullet. Imagine getting hit by six thousand rifle bullets, and you start to get an idea of why satellite collisions are not just catastrophic for the two birds involved, but also a danger to other objects in orbit as well.

So, maybe we all won't die- but the Earth just got a little bit more like RIFTS, in which we're all dead.

*Something stupid happened with the code I'm using to mash blogger into acting like a legitimate blog, and hiding the lengthy bits of my rambling posts. (Much like that sentence). So, I had to rig the rigged code into working, and the "Read More..." link is a permanent part of this post. Hopefully, this issue won't carry over into other posts.