September 11, 2013
Searching For the Origins Of Moon Water
[ Watch the Video: Origins Of Moon's Water Explored ]
John P. Millis, PhD for redOrbit.com - Your Universe OnlineRecent studies by NASA and the European Space Agency (ESA) have found that the Moon is wetter than previously thought - though it is still drier than the driest desserts on Earth. In turn, this has generated renewed interest in identifying the source of this water.
Now, a team from The Open University in the United Kingdom has found that a young, still forming Earth may have supplied the water now found in lunar rocks. By studying rocks returned to Earth during the Apollo Moon missions, they were able to identify the water concentrations in the mineral apatite, a calcium phosphate mineral prevalent in the lunar crust.
“These are some of the oldest rocks we have from the Moon and are much older than the oldest rocks found on Earth. The antiquity of these rocks make them the most appropriate samples for trying to understand the water content of the Moon soon after it formed about 4.5 billion years ago and for unraveling where in the Solar System that water came from,” Jessica Barnes from The Open University told Europlanet.
In addition to finding water laced within the crystalline structure of these minerals, their study also was able to analyze hydrogen isotopic signature of the water in an effort to identify the source of the molecules.
“The water locked into the mineral apatite in the Moon rocks studied has an isotopic signature very similar to that of the Earth and some carbonaceous chondrite meteorites,” says Barnes. “The remarkable consistency between the hydrogen composition of lunar samples and water-reservoirs of the Earth strongly suggests that there is a common origin for water in the Earth-Moon system.”
This is perhaps not all that surprising, as leading theories of the Moon’s formation contend that our closest neighbor was actually born out of the Earth itself. Early in the formation of our planet, it is believed that the Earth was impacted by a body roughly the size of Mars. As a result, a cloud of dust and other material formed in orbit high above the surface.
Over time the material, still hot from the collision, merged to form our Moon. While the natural conclusion to draw here is that the Moon’s water came from Earth, it is not entirely clear that water even existed on Earth at the time of the collision, as it was still hot and forming. In the end, this new result may shed some light on the timeline of events, and reveal the condition of our planet when the Moon was formed.