Study Reports Moon and Earth Share a Common Source of Water
Based from a new finding, scientists discovered that the water on the moon might actually be sourced from the same primitive meteorites that supplied most of the water on Earth. If these speculations are correct, the scientists raised more questions regarding the creation of the moon. Researchers have believed that the moon was created after an object collided with Earth nearly 4.5 billions years ago, leaving being a disc of debris that became the moon. If the moon were in fact created this way, it would be completely dry. However, new research reveals that the moon has water on and beneath its surface.
"The simplest explanation for what we found is that there was water on the proto-Earth at the time of the giant impact," the associate professor of Geological Sciences from Brown University and the study's lead author, Alberto Saal, said. "Some of that water survived that impact, and that's what we see in the Moon."
The researchers discovered water content on the moon after receiving samples from the Apollo Missions. They looked at the melt inclusions, which are tiny specks of volcanic glass that were trapped within crystals, from these samples. These crystals, known as olivine, capture water during an eruption, which allows researchers too analyze the insides of the moon. Based from these inclusions that contained water, the researchers wanted to identify the source of the water.
After conducting tests that measured the amount of deuterium and regular hydrogen in the samples, the researchers concluded that the moon's water source came from primitive meteorites and not comets. Deuterium is a hydrogen isotope and researchers have known that samples containing smaller levels of deuterium tend to originate closer to the sun. The ratio of regular hydrogen and this isotope in the melt inclusions led the researchers to believe that the moon's water comes from the common source that supplied water to Earth.
"The measurements themselves were very difficult," Hauri said. "But the new data provide the best evidence yet that the carbon-bearing chondrites were a common source for the volatiles in the Earth and Moon, and perhaps the entire inner solar system."
Since 98 percent of the Earth's water is believed to have come from primitive meteorites, the researchers believe that the water on the moon was most likely transferred from the Earth during the creation of the moon.
Saal worked with Erik Hauri from the Carnegie Institute of Washington, James Van Orman from Case Western Reserve University and Malcolm Rutherford from Brown University. The findings were published in Science Express.