The moon just got younger – by a few hundred million years.
Scientists now claim that the moon is around 4.4 and 4.45 billion years old, rather than the 4.56 billion years previously thought.
Despite being the nearest body to the Earth, astronomers are still not sure precisely how or when it formed.
One theory suggests the moon formed when a planet, around the size of Mars, collided with Earth around 4.56 billion years ago.
This collision divided Earth into two unequal parts. The smaller of these condensed into the moon
The best simulations of this process suggest that about 80 per cent of moon ought to have come from the impactor and 20 per cent from the Earth.
Scientists have long studied the moon’s crustal rocks to try and estimate its age.
As methods have improved, the most precisely determined age for the lunar rocks that arose is 4.360 billion years, the researchers said.
Meanwhile on Earth, scientists have found signs of a major melting event that occurred around 4.45 billion years ago.
From this, researchers have drawn the conclusion that the catastrophic collision that formed the moon occurred around 100 million years or so before.
‘There are several important implications of this late moon formation that have not yet been worked out,’ said Richard Carlson, of the Carnegie Institution for Science in Washington.
‘For example, if the Earth was already differentiated prior to the giant impact, would the impact have blown off the primordial atmosphere that formed from this earlier epoch of Earth history?’
The results were presented yesterday at a meeting organised by the Royal Society in London called ‘Origin of the moon.’
