Friday, October 29, 2010
at the same time we now have a general estimate of the number of Earth-sized planets in the universe. Those in our galaxy alone probably number in the tens of billions, and throughout the universe that gives about 50000000000000000000000 planets our size.
50000000000000000000000 planets means...
- every second these planets rack up 1.6 * 1016 years of geological history, and since the Earth was formed 4.5 billion years ago that means that:
- every second the entire history of 352000 Earths is being accumulated. My cats woke me up an hour and 50 minutes ago as they ran around the apartment trouncing each other and making all sorts of noise, so since then the universe's Earth-sized planets have clocked about 4 million Earth-history years all together. Approximately.
Also keep in mind that these calculations don't include moons similar to our size around gas giants, or those orbiting brown dwarfs and heated by tidal heating + a molten core and a thick atmosphere, as well as any rogue planets that might be out there.