The moon may be 100 million years older than we thought

[Admin]

The moon may have received a volcanic facelift, making it more than 100 million years older than rocks collected from its surface might suggest, a new study finds.

The moon may be 100 million years older than we thought : Read more

 

[Philly]

What is 100 million years between good friends?

 

[Torbjorn Larsson]

It explains much if fact such as the magma ocean crystallisation time, a lower number of impact basins than expected, the rarity of crustal metals that sank to the core and the rarity of zircons from before the remelt.

Arguable nitpicks:

The new study suggests the forces that Earth exerted on the moon would have led to widespread upheaval and intense heating.

The orbital resonance that was most heating was suggested to be the Laplace one at about 20 Earth radii distance as the Moon moved away due to (mostly) tidal heat dissipation. Then the effects on Moon's orbital presession from Earth *and Sun* was equal.

Two other major resonances were discussed. The Earth alone "evection" resonance happened at about 10 Earth radii, but they think Earth itself was too molten at the time to not itself dissipate. And the Moon alone Cassini transition at about 30 Earth radii (spin and orbit times equal), but at that time the orbit radius was too large for much heating.

Previous research suggested it formed between a collision between the newborn Earth and a Mars-size rock dubbed Theia, the last giant impact in Earth's history.

The 20 % as massive Theia contributed about 10 % of Earth mass and remelted it. Geological societies have suggested that we should call the proto-Earth Tellus and the collision result Earth.