Friday, 16 September 2016

Potassium Kills Moon Origin Hypothesis

Potassium isotopes in lunar rocks like this killed the leading Moon origin hypothesis. Image courtesy of NASA.

Joel Kontinen

Secular Moon origin hypotheses have not fared well recently.

And the ones that do make it into headlines rely too much on fiction and speculation.

The latest casualty is the view that relies on the collision between a Mars-sized body and a proto-Earth. A paper in Nature compared the potassium-41 and potassium-39 levels in lunar rocks and terrestrial rocks.

Science Daily summarises the results:

The leading theory for the moon's formation got in trouble recently when it was revealed that the moon and Earth are isotopic twins. Now highly precise measurements of the isotopes of an element that was still condensed at the ‘cut off’ temperature when material started to fall back to Earth suggest a dramatic solution to the problem.

The expression ‘got in trouble’ is an understatement. The hypothesis or story is practically dead.


Washington University in St. Louis. 2016. Moon is proto-earth's mantle, relocated, chemistry suggests. Science Daily. (12 September).