The new study brings scientists one step closer to answering the question of where Earth’s water comes from.
Water makes up 71 percent of the Earth’s surface, but no one knows how or when that large amount of water arrived on Earth.
The new study published in the journal Nature bringing scientists one step closer to answering that question.
Led by University of Maryland Assistant Professor of Geology, Megan Newcombe, the researchers analyzed melted meteorites that have drifted through space since the formation of the solar system 4.5 billion years ago.
They found that these meteorites have an extremely low water content – in fact, they are among the driest extraterrestrial material ever measured.
These results, which led researchers to rule them out as the main source of water on Earth. It could even have important implications for the search for water—and life—on other planets. It also helps researchers understand the impossible conditions that go into making Earth a habitable planet.
“We want to understand how our planet gets water because it’s not entirely clear,” Newcombe said. “Getting water and having oceans on the surface of a planet that is small and relatively close to the sun is a challenge.”
The research team analyzed seven molten meteorites, or achondrites, that fell to Earth billions of years after breaking apart from at least five planetesimals — objects that collided to form the planets in our solar system.
Newcombe and his colleagues analyzed small pieces of these seven meteorites; each chip is a few millimeters wide.
In a process known as melting, many of these planetesimals were heated by the decay of radioactive elements in the solar system’s early history, causing them to separate into layers with a crust, mantle, and core.
Because this meteorite had recently fallen to Earth, this experiment was the first time anyone had measured its volatiles.
UMD geology graduate student Liam Peterson uses an electron microprobe to measure their levels of magnesium, iron, calcium and silicon. Then he joined Newcombe at the Carnegie Institution for Science’s Earth and Planets Laboratory to measure its water content with a secondary ion mass spectrometry instrument.
“The challenge of analyzing water in very dry material is that any terrestrial water on the surface of the sample or in the measuring device can easily be detected, contaminating the results,” said study co-author Conel Alexander, a scientist at the Carnegie Institution for Science.
