Saturday, April 5, 2008

Physics in the realm of Hollywoodland!

'Armageddon:' Last by a longshot
Everett Collection via

'Armageddon:' Last by a longshot

Oh "Armageddon," where do we begin? Brought to us by master-of-realism Michael Bay, this 1998 film is among cinema's worst physics offenders. Let's try to tackle one of its most hilarious distortions of reality, the one at its core — that a nuclear warhead placed on an asteroid the size of Texas could successfully blow it apart, preventing a catastrophic collision with Earth.

Let's ignore the fact that asteroids don't have fault lines, and if they did, they would not be easily detectable. Let's also put aside the fact that the prescribed 800-foot-deep hole in a Lone Star–size asteroid (Texas is 700 miles wide) would barely even scratch the surfaceonly get you 0.0004 percent of the way to the center. Or that Bruce Willis and friends miss their landing site by 26 miles, presumably putting keeping them away from the "fault line" anyway. Let's just focus on the amount of kinetic energy needed to blow an asteroid apart, and for its two massive halves to move far enough (one Earth-radius perpendicular to the impact trajectory) to miss the Earth in the three hour and 56 minute timeframe that marks this mission's absolute deadline.

Granted, this calculation assumes a ton of ideal conditions, which almost certainly wouldn't exist. But even in a perfect scenario, a certain kinetic energy would be necessary to separate the asteroid halves and propel them at the required 460 m/s. The biggest warhead built to date has a yield of 100 megatons. That's one one-hundred-millionth of the energy Bruce would need to save Earth — making this flick a bomb in more ways than one.

Original here

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