Is this a used planet ?

I'm sorry, but tom4bucks cracked me up. The age of the earth has nothing to do with the magnetic poles. Many pole reversals are recorded in the long solidified, alternating magma floes forming the mid-atlantic ridge. And , LOL, one *should* consider the evidence for a 4.5 billion year earth to be as good as the evidence for global warming! They have both been confirmed beyond a reasonable doubt.

Blondnirvana, I'm not sure what you mean by the planet being "used" but there has almost certainly been no intelligent life indiginous to this planet before humans. The first humans came into existence about 4 million years ago. This depends on how you classify them. The earth is a thousand times that old. During that time life went from pre-cellular replicating complex molecules to all the diversity we see today.

Edit: Oh, I looked up your Q&A because I couldn't figure out if I saw you here or in Yahoo Personals. So I see that you are a very legitimate and knowledgeable science fan and this question was tongue-in-cheek. Guess I feel silly, now.

Well acording to theory we may not have a used planet but aplanet reformed many of times. Possibly by comets or other bodies in space. Which could have created our moon as well. Which we wouldn't have seasons, ocean currents, and the earth wouldn't even rotate the same. So I look at the earth as a work possiblyeven still in progress.

In response to the magnetic poles above... they reverse every several thousand years. Interesting events too; one of the reversals is probably what killed Mars. Evidence of that has been found in stratified rock layers... namely, volcanic rock that allows the melted material to align with the magnetic poles. Some time areas, it's 'normal,' whereas in other areas, it's 'reversed,' and in some, it's crazy.

Well, the dinos were some of the more major ones to inhabit the Earth. I mean, you can go to Cambrian and stuff, but it's mostly ocean stuff there.

Well - if you figure half life of the magnetic poles

we can't be over 14, 000 years

I put the strong evidence of 4.5 bill yrs right along side

global warming

used planet - no way - we get a brand new day every day!

best of all ! your in it!

plants, fish, and then dinosaurs, and I would be grateful for the planet we got, and now we are destroying it.