Well, here is an interesting twist. Low pollutant energy, and it could help cool the planet! linkasurous edit: silly fun fact of the day... Q. Does the entire earth spin at the same rate? A.The solid inner core -- a mass of iron comparable to the size of the Moon -- spins faster than the outer portion of the iron core, which is liquid. A study in 1996 showed that over the previous century, the extra speed caused the inner core to gain a quarter-turn on the planet as a whole. So the inner core makes a complete revolution with respect to the rest of Earth in about 400 years. Immense pressure keeps it solid. From the live science web site. I'm not really smart enough to know that kinda thing.