Perhaps there is more life in the universe where the base energy source is that of geothermal than that of radiation from a star? I wonder what an sentient life form evolved from this environment would be like?
I feel a short story coming on.
Potassium-40 (1.2 billion years) is the highest.
Isn't that more, or do I just fail at basic math?
Solar energy on the other hand clocks at 173 petawatts (of which 30% is reflected, so that makes it 120).
EDIT: Never mind, correct link: http://en.wikipedia.org/wiki/Earth%27s_energy_budget