Earth’s water didn’t come from meteorites, study says

Water makes up about 71 percent of Earth’s surface, but how it got to the planet continues to puzzle scientists after a new study ruled out a leading possibility.

Scientists, however, are one step closer to understanding how water came to be on Earthaccording to research published in the journal “Nature” on March 15.

Previous studies have suggested that molten meteorites that have been “wandering” through space since the formation of the Solar System four and a half billion years ago may be the cause.

But the new study says these meteorites had “extremely low water content”. In fact, they were some of the driest extraterrestrial material ever measured, the study said.

“These results, which allow researchers to rule them out as a major source of water on Earth, could have important implications for the search for water and life on other planets,” the study said.

A team of researchers led by the University of Maryland analyzed seven molten, rocky meteorites that collided with Earth billions of years ago. The team was able to pull up debris that showed these meteorites were pieces of planetesimals, objects that collided to form the planets in our solar system.

As the planets were heated by radioactive elements during the early history of the Solar System, more pieces were separated.

The meteorites tested recently fell to Earth, making the new study “the first time anyone has ever measured their water content,” the researchers said.

Earth’s water did not come from molten meteorites, according to a new study that analyzed molten meteorites that have been floating in space since the formation of the Solar System four and a half billion years ago. (Illustration by Jack Cook, © Woods Hole Oceanographic Institute)

The scientists left some samples under a high-powered vacuum for more than a month to suck up enough water for testing.

When the experiment was over, the meteorites failed to offer a solution to where Earth’s water came from.

“We knew that many objects outside the solar system were different, but it was kind of implicitly assumed that because they were outside the solar system, they must also contain a lot of water.” Sune Nielsen, Associate Scientist, Geology and Geophysics at Woods Hole Oceanographic Institution, said in the press release. “Our paper shows that this is definitely not the case. As soon as the meteorites melt, there is essentially no water left.”

Some of the samples used were from the inner solar system (where Earth is located), while other “rare” samples came from the cooler, icy outer regions of the solar system.

“Although it has generally been assumed that water came to Earth from the outer solar system, it remains to be determined what types of objects could have transported this water through the solar system,” the study said.