Lectures on Physics has been derived from Benjamin Crowell's Light and Matter series of free introductory textbooks on physics. See the editorial for more information....

Energy released by a comet impact

Comet Shoemaker-Levy, which struck the planet Jupiter in 1994, had a mass of roughly 4 1013 kg, and was moving at a speed of 60 km/s. Compare the kinetic energy released in the impact to the total energy in the world's nuclear arsenals, which is 2 1019 J. Assume for the sake of simplicity that Jupiter was at rest.

Since we assume Jupiter was at rest, we can imagine that the comet stopped completely on impact, and 100% of its kinetic energy was converted to heat and sound. We first convert the speed to mks units, v = 6104 m/s, and then plug in to the equation to find that the comet's kinetic energy was roughly 7 1022 J, or about 3000 times the energy in the world's nuclear arsenals.

Last Update: 2009-06-21