According to new analyses, the moon is between 80 and 180 million years older than previously assumed. Researchers report that the tidal effect of the Earth heated the Earth’s satellite once again 4.35 billion years ago, and magma from the interior reached the surface. The age of most of the rock samples reflects the magma’s cooling and not the moon’s formation.
Shortly after the primordial Earth formed around 4.5 billion years ago, there was another huge collision in the solar system: the Mars-sized celestial body Theia collided with the primordial Earth. The collision catapulted large quantities of glowing rock from the crust and mantle of the two celestial bodies into space—the moon was formed from these remnants of the planetary catastrophe.
But when exactly did this happen? Rock samples brought to Earth by the “Apollo” astronauts and a series of unmanned missions provided an age of 4.35 billion years for the cooling of the lunar surface. This was previously considered to be the age of the Earth’s satellite. However, researchers also found crystalline inclusions in the lunar rock, known as older zircons. This raised doubts about the assumed age of the moon.
Strong tidal forces
Francis Nimmo from the University of California, Thorsten Kleine from the Max Planck Institute for Solar System Research, and Alessandro Morbidelli from the University of Sorbonne have now presented a solution to the dilemma in the journal “Nature.” According to the paper, the newly formed moon followed a highly elliptical orbit close to the Earth. In the process, the Earth satellite went through a phase of powerful tidal forces that heated its interior, transported magma to the surface, and thus caused an apparent rejuvenation.
The three researchers’ considerations now provide an age of 4.43 to 4.53 billion years for the moon. The scientists emphasize that this age also fits much better with the dynamic models of planet formation in the solar system.
- source: science.ORF.at/picture: Image by Van Fulpen from Pixabay
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