OK, I'm giving away the ending, so don't say I didn't warn you... At the end, Superman lifts Luthor's new landmass into space. I did some rough hand calculations to figure out how much energy Superman had to use to lift the island into space. Judging from the scale presented in the movie, I'm estimating the island was roughly 5 miles in radius, 5 miles thick. This yields a volume of pi * 5^3 ~ 400 cubic miles = 1.7e12 cubic meters. Given that the island appears to be made of a material similar to Quartz, with a density of 2600 kg/m^3, this gives us a total mass of 4.3e15 kg. Escape velocity at the Earth's surface is 11,000 m/s. Assuming that Superman accelerated the object to not much more than escape velocity, that gives us 1/2 * 4.3e15 kg * (11000 m/s)^2 = 2.6e23 joules. Hiroshima was 6e13 joules. So this act is equivalent to exploding about 4.4 BILLION Hiroshima bombs! Anyhow, just thought I should share... :) Edit: Whoops, forgot to square the velocity.