No Bomb Powerful Enough To Destroy an On-Rushing Asteroid, Sorry Bruce Willis 352
coondoggie writes "Maybe it's the doom predictions about the end of the Mayan calendar this year, or maybe these guys are obsessed with old Bruce Willis movies. Either way a class of physics students from the University of Leicester decided to evaluate whether or not the premise of Willis' 1998 'Armageddon' movie — where a group of oil drillers is sent by NASA to detonate nuclear devices on an asteroid that threatens to destroy Earth — could actually happen. The students found it would take a bomb about a billion times stronger than the biggest bomb ever detonated on Earth."
Re:not about destroying (Score:5, Interesting)
is it me or did the class get it wrong, it was never about destroying an asteroid, it was about splitting it up in pieces or nudging it out of the earth direction
Exactly what I was thinking: Define "destroy". Do they mean completely vaporize or just something that will do the job?
Re:not about destroying (Score:5, Interesting)
Indeed. A small nudge, if applied when the asteroid is still some distance from Earth, could have a considerable impact on it's trajectory. That would make an interesting project, simulating the relationship between time to asteroid, payload, asteroid mass and what not to determine how quickly we would need to react.
Easy answer - bomb contained a black hole (Score:5, Interesting)
Either than or about the fiftieth continuity or stupidly ignored fact failure of the movie.
There were Highlander sequals that made more sense - even the one where the sword changed from claymore to katana and back again in the middle of a fight.
Re:not about destroying (Score:5, Interesting)
Arthur C. Clarke's book, "The Hammer of God" was about this exact topic. It featured all kinds of neat furistic technology, like making a huge detonation in the solar system to emit a huge burst of EM radiation to find dark asteroids, and trying to put a mass driver on an asteroid to nudge it off course. It also had a great depiction of a lunar marathon.
All in all, I thought it was a pretty enjoyable read.
Re:A billion times. (Score:5, Interesting)
Very doubtful. But we could potentially build such a bomb if the Earth depended on it for some reason; the Teller-Ulam configuration scales indefinitely. The problem is it'd be way too massive to get off the ground.
Of course, these students were simply calculating the (very unrealistic) scenario found in the movie, of the asteroid right about to impact, and of deflection involving splitting it in half and having one half go each way around the Earth. As they note, more realistic deflection scenarios involve hitting it much earlier and simply trying to alter it's trajectory intact (but that's not fitting for Hollywood)
Also it should be noted that the Tsar Bomba mentioned in the article was deliberately cut down to half of its design yield (replacing the uranium tamper with a lead one) to make it burn cleaner. It was not only the biggest atomic bomb ever detonated on Earth, but also the cleanest per unit of energy output.
Re:not about destroying (Score:5, Interesting)
I assume everyone here has played around with the Earth Impact Effects Program [ic.ac.uk]?
Re:not about destroying (Score:4, Interesting)
You can imagine the standard assumption to be that an asteroid is very hard, and that an atomic bomb would mainly give it a good shove that does not break the integrity of the asteroid, and that the heat can be neglected.
Compare instead an asteroid to be a loose snowball and the bomb to be mainly good at breaking it up and heating it.
Except that asteroids are not loose snowballs. Even a nuke is too weak to break up anything larger than, say, half a kilometer into pieces - or rather, an point explosion is a rather inefficient way of using that amount of energy. And even if it somehow got split, its own gravity would hold it together.
(This is, BTW, why the Death Star blowing up Alderaan into pieces in Star Wars is a load of crap - you can see rather solid pieces of matter flying away from the explosion, but the scale doesn't match. The kind of energy capable of instantly propelling a planet-sized load of matter at a few thousand kilometers per second by means of a central explosion with a shock wave would turn the whole thing into plasma instead. (I guess that mentioning that the whole cloud would be rather poor in visible spectrum is a minor bickering at this point.))
Re:not about destroying (Score:5, Interesting)