FILE - In this Thursday, July 21, 2005 file photo, the full moon rises behind the ancient temple of Posseidon, in Sounio about 73 kilometers (45 miles) southeast of Athens. That old moon might not be as antique as we thought, some scientists think. They say it's possible that it isn't a day over 4.4 billion years old. But other astronomers disagree with a new study's conclusions. They think the moon is up to its typical age-defying tricks and is really pushing 4.6 billion as they have suspected all these years. Either way, the new analysis of an important moon rock brought back by the Apollo 16 mission is showing that the moon isn't ready to give up its true age and origins quite yet, even though scientists thought they had it all figured out a decade or two ago. (AP Photo/Petros Giannakouris)
Tags: Moon Rock