Astronomers provide with a new tool to determine the age of major events in the early history of the solar system. Now they have found the age of the Moon and also the starting point of the Earth, how it began to become the world that we know today.
The view that the collision between a Mars-sized planet and the early Earth formed the Moon is now generally accepted, however the accurate timeline of the event is still uncertain. With this, the ages of the most ancient lunar samples returned by the Apollo astronauts still being debated, for the reason that of disagreements about the isotope systems used for dating.
Research point outs numerous kilometre-sized fragments from the massive impact crash into the main asteriods belt between Mars and Jupiter at much higher velocities than typical main belt collisions, heating the surface and leaving behind a permanent evidence of the impact.
According to a new study of meteorites that provides clues to the giant collision which formed the Earth and the lunar body, the Moon is actually about 4. 47 billion years old.
The study was led by Bill Bottke of Southwest Research Institute which used numerical simulations to show that the giant impact likely created a disk near Earth that eventually coalesced to form the Moon, while ejecting huge amounts of debris completely out of the Earth-Moon system.
Published in the US journal Science that less violent collisions between asteroids have ejected some shocked remnants back to Earth in the form of fist-sized meteorites.
They wrote, “By modeling their temporal evolution, and fitting the results to ancient impact heating signatures in stony meteorites, we infer that the Moon formed about 4.47 billion years ago, which is in agreement with previous estimates.”
The team also proposed that the moon-forming giant impact was the biggest and most recent known collision in the inner Solar System.
Intriguingly, over time scales ranging from tens of thousands of years to 400 million years some debris may hit the Earth and Moon after remaining in solar orbit.
“The importance of giant impact ejecta returning to strike the Moon could also play an intriguing role in the earliest phase of lunar bombardment. This research is helping to refine our time scales for ‘what happened when’ on other worlds in the Solar System,” said Bottke.