For several years now, we've known that the Moon is not as dry as was assumed for decades, in fact our satellite is harboring a good amount of water. Now a team based at the Open University in the UK is painting a more detailed picture of exactly how that water was transported to the Moon and trapped on what seems like an outwardly arid rock.
Initial hypotheses assumed that comets were the most likely delivery source for the water found in the interior of the Moon and even near the surface of its soils, but scientists using data from recent unmanned lunar missions like the Lunar Reconnaissance Orbiter and Deep Impact more recently established that water-rich asteroids may have been responsible for most of the water in the Moon.
The mystery that has remained is when all the water in the Moon arrived there and how much came from asteroids versus comets.
A team led by Jessica Barnes at the Open University used numerical models and data from lunar samples used in previous studies to find that water was delivered to the Moon's interior soon after its formation over a period of 10 to 200 million years.
The Moon is thought to have formed about 4.5 billion years ago after another planet-sized object collided with the Earth. In its early days, an ocean of magma was active on the Moon. Barnes and colleagues believe it is during this period that a class of asteroids known as carbonaceous chondrites rich in water delivered as much 80 percent of the Moon's water, with comets making up most of the smaller portion of that total water budget.
The model Barnes' team used describes comets and asteroids colliding with the Moon's magma ocean and a thermal lid forming at the surface of that ocean to prevent the water within the visiting space rocks from being lost into space via degassing.
The results find that most of that water could be retained in the Moon's interior until today and that most came from asteroids, although some may also be traced back to the primordial Earth itself and the initial impact that formed the Moon.
The results are published today in the journal Nature Communications.
Source: Nature
Saying '..Thought to have..' is pure speculation and conjecture and lacks one quite important thing: Science.
The water, however, on the moon came from earth. The light is over here: creationscience.com
To put it simply, and I am far from being an astrophysicist, it would seem logical to conclude that the Earth and its moon may be of similar composition, and since the Moon lacks an atmosphere, any water present would be beneath the surface. The claim that the Moon may be an indicator in suspension showing what happened to both bodies is an interesting one.
Then why do they look so different? My suspicion is that the Earth has had plate tectonic activity over the course of billions of years because it has a hot core, while the Moon’s is much cooler or hasn’t one at all, since there is virtually no comparative volcanic activity on its surface.
This begs the question of why are we spending so much energy and resources for Mars when we should have been obtaining core samples from the Moon years ago to unravel the story of this fascinating neighbor of ours.