A biography of the Earth

4.4 billion years ago, the earth was a toxic place with no hope of life. Then, a giant planet called Thea crashed into the earth. Over millions of years, our oceans formed. Plants were formed. Life started forming in the oceans. Over millions of years people and land animals formed. But what does this have to do the environment? Well, first let's look at the movie Wall-e. The fat caption said the ship had been in space for 700 years before Wall-e discovered a plant. So they all went home and lived happily ever after. Time for the non-fiction version. 1,000 years later- first plant found. 3,000 years later- all the trash cleaned up. 3,500 years later- Enough oxygen for human life. 4,000 (or more) years later- human life sustainable( finally). The point here is that it's going to take a while to clean up the earth if we mess it up. We only have one planet sustainable for human life. We need to keep it this way, or we're all going to die, either in space, or here on earth.