My Blog for Physics in Film

My scenerio is the classic asteroid t-bones the earth. So, we have this asteroid coming towards us, it is traveling at 11,000 m/s and it is the size of a Midwestern state. I will use the asteroid Ceres 1 as a reference (wiki). It has a mass of around 9.43e20 kg. So the asteroid is coming perpendicular to Earth. Therefore I feel that it would only be necessary to slow the asteroid a little bit so that Earth will “be late” for its disaster appointment. So, my goal is to see how much time we would need to slow down the asteroid using a 150 megaton warhead. So, the earth orbits the sun at a velocity of about 29 km/s (source: http://hypertextbook.com/facts/2000/ IlanaEpstein.shtml). The earth is roughly 12,700 km across (wiki). Therefore it would take the Earth 437 seconds to move out of the way of the path. Is a 150 megaton warhead enough to give us that much time?

So let us see how much the warhead would slow the asteroid. 150 megatons is about 6.276e17 J. The asteroid current has (1/2)( 9.43e20 kg)(11,000m/s)^2 or 5.7051500e28 J of kinetic energy. If all the energy of the bomb goes towards decreasing the amount of kinetic energy of the asteroid, then the asteroid would then only be traveling with 5.7051499e28 of kinetic energy. Solving for the new velocity we get 10999.99986 m/s which equates to roughly 1 m/s less speed (and that Is pushing it but there has to be some change) at 10,999 m/s. So let us say that the asteroid is 1 year (31,556,926 s) from impact. This equals a distance of 3.4712618e11 m using the initial velocity of 11,000 m/s. At 10,999 mi/h, it would travel that distance at In 31,559,795 s, this is 2,869 later than it would be without the blast. This is good news for Earth. Even if the change in velocity were less, we could save ourselves from certain doom barring human and/or calculation error. We just have the get a nuke out there as soon as possible and just give it a nudge, the farther out, the better. Problem solved