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Study: Moon Is 4.51 Billion Years Old

For almost as long as people have walked on Earth, they have looked up at the moon and wondered: How did the moon get there? How long has it been there?Scientists have studied these questions. And now, a group of researchers from California have an answer. Based on their studies, they think the moon is 4.51 billion years old. For years, researchers have been studying the many rocks American astronauts brought back from the moon between 1969 and 1972. The early rock studies led many scientists to think the moon was formed long ago -- about 4.3 billion years ago.

Scientists believe the moon was created when a huge rocky object about the size of Mars struck a very young Earth.  Then some of the pieces from that violent crash came together in space to form the moon. But that estimated age, 4.3 billion years, created a problem for scientists.

 That is because it does not leave much time for life to get started and develop on planet Earth. Melanie Barboni is a researcher in the Department of Earth, Planetary and Space Sciences at the University of California, Los Angeles (UCLA). "Here at UCLA, there has been this study that has found that life could have appeared as early as 4.1 billion years old. So now if you believe the giant impact occurred at 4.3, it doesn't leave you a long time between the impact and basically the Earth being half destroyed and then the Earth acquiring all the conditions you need for life."