Where did the moon come from?

For a long time most astronomers have believed that the moon formed when another planet, around the size of Mars collided with the Earth early in the formation of the solar system. In science, theories are constantly being changed and challenged though. Just today an article appeared in Scientific American that presents evidence contrary to this formation theory. It seems that a group of scientists studying some rocks brought back from the moon have found that the amounts of certain titanium isotopes are nearly the same on the moon as they are on the earth. This is important because if the moon had formed when another planet hit the earth then the moon's chemical properties should be pretty different from the earth's. This challenge by no means that the moon cannot have formed from a collision but it does make that particular theory harder to prove. One of the jobs of a scientist is to keep an open mind and always be ready to change theories and opinions based on new evidence. That's something that many people from all kinds of different fields should keep in mind! Check out the full article from Scientific American by clinking this link.