Hello Earth - Origins of Our Planet - Part II
What clues do scientists use to understand the creation of our home planet? The best clues that scientists have come from the study of distant young stars, and the new planets forming around them. By studying these young suns, they can catch glimpses of the creation of their new baby planets, and of their young planetary systems.
But wait a minute. Are we saying that scientists can actually watch planets as they form around distant stars? Well, not exactly. First of all, these distant planets are so far away that they are too small for us to see them using modern technology. Secondly, planets do not form over night. They take millions, and even billions of years to develop. Thus, even if we could see these planets, all we would see is how they look today. Unless we watched them for many hundreds of millions of years, we would not be able to learn much about how they evolved.
So then, how do we learn about our own planet's birth and growth? In our Universe there are literally trillions and trillions of stars. The number of stars in our universe is vast and unimaginable. Many of these stars have a family of planets orbiting them. Each of these planetary systems is a different age. Some of them are very old, and some of them are very young.