The bright nuclear minds at Los Alamos National Laboratory aren’t finished coming up with novel ways to blow things up. Right now, they’re using a 32,000-processor rig to simulate a nuclear attack against an incoming asteroid. Above, a one megaton “nuclear energy source” (warhead) hits the Itokawa asteroid — half a kilometre wide. And good news! The blast and subsequent shockwave would be enough to “mitigate” the rock’s threat to our tiny planet. Which means it wouldn’t kill us all, right? Why don’t we bump it up to two megatons, gents. [Los Alamos]
Antipodean
Saturday, February 11, 2012 at 10:31 AMEven if the thing wasn’t detected until it was only a couple of weeks out, nukes are going to be the answer. I know most people in this field think turning a big rock into a lot of smaller ones is a bad idea, but I think I’d rather have a lot of smaller ones coming in, which will mostly get burned up on entry and the rest will no doubt cause global bombardment, but they won’t cause a an extinction event either.
Andrew
Saturday, February 11, 2012 at 10:58 AMNot to mention that if they can slow it down, earths orbital velocity around the sun staying the same, it will pass behind us.
Michael
Saturday, February 11, 2012 at 12:37 PMEven planting several nukes at a right angle to it’s path of travel, then detonating then one by one, should provide enough force to push it away.
Sean
Saturday, February 11, 2012 at 1:03 PMIt’s not quite that simple in space. To push the asteroid one direction, you need to push something else in the other direction. Detonating a nuke next to it will pretty much just make it really hot on that side. You need some way of using the nuke to eject some of the mass in a specific direction. Just vaporizing a surface layer might not be enough.
Charliem
Sunday, February 12, 2012 at 3:48 AMSean – I think thats what this video is actually trying to tell you….that with enough of a blast, you can alter the trajectory of the object.
Sam
Monday, February 13, 2012 at 3:38 AM4.184×10^15 J = 1 Mt
K = 1/2m x V^2
assuming 1% of all the energy released from a nuke is kinetic that means that roughly 4.184×10^14 J of kinetic energy would be exerted outwards, assuming only 10% of this energy transferred from the ejected matter to the asteroid and that would mean 4.184×10^12 J of kinetic energy would be exerted on the asteroid.
now we take into account the weight of the asteroid to account (3.5×10^10) and find out the blanks
D(K) = 1/2M x D(V^2)
D(V^2) = D(K)/(1/2M)
D(V) = (D(K)/(1/2M) ^ 1/2
D(V) = (4.184×10^14 / (1/2 x 3.5×10^10)) ^ 1/2
D(V) = (4.184×10^14 / 1.75 x 10 ^ 10) ^ 1/2
D(V) = (2.4×10^4)^1/2
D(V) = 1.5×10^2 m/s
so therefore a 1 megaton nuke could change the velocity of the asteroid by roughly 150 meters per second or ~540 Km/h, that change, if completed far enough out, could save to world, if done correctly one could also theoretically push an asteroid into orbit effectively adding a new moon
Disclaimer: I am no scientist, this math may be completely wrong (i’m not sure how much of the energy from a nuke is kinetic and I don’t know how much of this energy would be transferred to the asteroid, I low balled it on purpose)
Sean
Monday, February 13, 2012 at 12:19 PMNice work. But unfortunately almost none of the energy of a nuclear blast in space is kinetic. The only mass is the structure of the weapon itself. The energy released is almost entirely electromagnetic in the form of penetrating radiation – gamma and x-rays. The blast we associate with nuclear weapons comes from the superheating and expansion of the surrounding matter e.g. the atmosphere. If your nuke superheats some of the asteroid to a point where it vapourises and explodes off the surface, then you will suceed in giving it some level of impetus in the opposite direction. Calculating this impulse would depend on a lot of factors, hence the simulations, but it’s more complicated than just setting off a series of devices at 90deg to the direction it is travelling. The process would send a shockwave through the asteroid, so it’s probably easier to break it up than it is to deflect it.