A lot of the Moon's water may need come from asteroids
For some time, scientists believed that water contained in the Moon largely got here from comets. Nevertheless, they could should rethink that perception. Researchers taking a look at Apollo mission lunar samples now suspect that a lot of the Moon’s water got here from asteroids smacking into the celestial physique between four.three billion and four.5 billion years in the past, when it (and the Earth) was coated in a magma ocean. The important thing was to take a look at hydrogen isotopes. Whereas comet water tends to be wealthy in deuterium, lower than 20 % of the Moon’s water exhibits indicators of it — the isotope ratios have been usually nearer to that of the Earth, pointing to an asteroid origin.
There’s even a risk that as a lot as 1 / 4 of the Moon’s water got here from the extensively theorized Theia influence with the Earth round four.5 billion years in the past, which might have shared materials each instantly and thru asteroids.
The issue with the asteroid idea, as you may guess, is a relative dearth of data. Scientists have solely examined 2 % of the Apollo samples up to now, they usually’re all from the close to aspect of the Moon. It is attainable that additional research (particularly from the far aspect) will inform a unique story. Fortunately, these missions are coming — the idea might get further help within the years to return.