Is there a cosmologist in the house? I've got a basic understanding (with some degree of error) of some simple facts:
- The Universe is a little over 13 billion years old. Our galaxy is almost that old.
- Our solar system is roughly 4.6 billion years old.
- The heavier elements (Carbon, Oxygen, etc..) are only produced by stars.
When our solar system coalesced, the stuff that makes up the planets came from a previous generation of stars. (Meanwhile our Sun is busy making its own slightly-heavier elements, but those aren't ours. Those belong to the next "generation" after our star dies.)
So we're all sitting on a rock whose matter was spewed out of a star (or stars) that preceded this solar system. Got it. Don't need that lesson. But what I want to know is...
How many cycles of coalescing, fusing, doing the nucleosynthesis thing, exploding -- and then repeating the cycle -- have this atoms in this ball of rock I'm standing on been through?
How do you know this? Can you tell by the make-up of the matter in the solar system? Looking around the Orion arm to see remnants of our former home? Wild ass guess?