Earth’s water, including what’s in your glass or morning shower, is older than the sun. According to a study published on Thursday by Science, much of the water on our planet was introduced from elsewhere in the galaxy and not formed, as many scientists have thought, by chemical reactions occurring during the formation of the sun. While the extraordinary age of Earth’s water may seem inconsequential, it suggests that there might be a lot more of it floating around somewhere in the Milky Way, maybe even incubating alien life; and that information has the potential to be a very big deal.
“If our sun’s formation was typical, interstellar ices, including water, likely survive and are a common ingredient during the formation of all extrasolar systems,” study lead author Lauren Cleeves, a Ph.D. student at the University of Michigan, told Space.com. “This is particularly exciting given the number of confirmed extrasolar planetary systems to date — that they, too, had access to abundant, life-fostering water during their formation.”
The researchers behind the study came to their conclusions by using a little bit of chemistry. About one in every 3,000 molecules of water on Earth contains deuterium, a sort of hydrogen mutant that has a neutron in addition to a proton (most hydrogen atoms simply have a proton). Water with a deuterium atom in it has a slightly greater weight, giving it the name ‘heavy water.’ What makes deuterium interesting is that it can only form in high quantities under certain circumstances; specifically, an extremely cold environment with lots of energy. This makes the high quantity of deuterium on Earth sort of an odd circumstance.
After running a few complex computer models, Cleeves, alongside the team with which she worked, discovered that the amount of deuterium containing ‘heavy water’ could not have been produced during the formation of the Sun. “This was an ‘aha’ moment for us – without any new water creation, the only place these ices could have come from was the chemically rich interstellar gas out of which the solar system formed originally,” Cleeves told Discovery.
Currently, the researchers estimate that 30 to 50 percent of the water on Earth came from somewhere else in the Galaxy. Still, scientists are not exactly sure where all the water came from, reports The Los Angeles Times. Some, like Cleeves, hypothesize that the water was there in the protoplanetary disk from the beginning, and was part of the building blocks of our solar system’s formation. Others suggest that icy comets or asteroids, coming from cooler environments, crashed into the newly-born Earth, soon after the Sun had formed, and brought with them ancient water.