Moon Origins

24 Nov 2017

Sent in by Gary. At .... the Moon's surface was a magma ocean - until it solidified. How long did that take? We are told that long before the Moon came to be covered in a solid and cratered crust (the situation nowadays) it was a massive ocean of molten magma. One theory is that this accounts for the crust's so called purity - it is primarily made up of a single mineral. A new study suggests a secondary event may be to blame. At some point the lunar crust was turned inside out - replaced by younger hot deposits from the interior. The mineral plagiocase makes up 98 per cent of the crust. It seems the molten magma theory had a problem - hence the adjustments put forward in this new study. This is that the Moon cannot have cooled quickly in the initial impact and molten magma model. In other words, the moon probably did cool quickly and this is an attempt to explain that fact ....

  ... the piece then describes the experiment to test the theory. It also describes the currently fashionable theory of the Moon's origin following an impact of the Earth with another cosmic body. One mystery still remains. Why are the Moon and the Earth so similar in their composition. Several theories have been created to account for this - just as several theories exist on the origin of the Moon.