Water On Earth And The Moon May Have Come From The Same Meteorites

According to new research, water found deep inside the Earth and the moon may have originated from the ancient meteorites. Some scientists now believe that water already existed on Earth prior to the impact that created the moon, and subsequently, the moon would've begun with a portion of that supply.

Until very recently, scientists thought that the interior of the moon was dry, with the theory that the heat of the collision that created it would've destroyed all of the ingredients for water. Five years ago however, evidence of hydrogen was found in lunar samples from the Apollo missions, leading researchers to believe that water may have existed in the moon long ago.

After analyzing these hydrogen isotopes, scientists have discovered that similarities between Earth-borne and these lunar samples. Isotopes of hydrogen all have the same number of protons, but will differ on neutron counts. Regular hydrogen has no neutrons, while the isotope deuterium has one. As a general rule of thumb, objects formed closer to the sun will have less deuterium.

Scientists have discovered that the ratio of deuterium to hydrogen seen in meteorites known as carbonaceous chondrites is similar to the water on Earth, leading them to believe that much of our planet's supply came from these space rocks. Scientists estimate as much as 98% of Earth's water came from these sources.

Additionally, scientists found that the ratio of deuterium to hydrogen in moon rocks is likewise similar to Earth's, which may indicate that both the moon and our planet share an origin in carbonaceous chondrites meteorites.

"With a good degree of certainty, we know that the water came to the moon and Earth from primitive meteorites now located in the outer parts of the asteroidal belt," said lead author Alberto Saal, a geochemist at Brown University.

Researchers now believe that the best explanation for the similar ratios is that water was transferred to the moon "during the giant impact without completely being lost by this event."

The study was published in the journal Science.