Scientists make step towards solving mystery of where Earth’s water came from


Scientists have made a step towards solving one of Earth’s biggest mysteries: where did all the water come from?

Some 71 per cent of our planet is covered in water, but scientists still do not know how it got here, or why we have so much of it.

The mystery not only covers our planet but the search for alien life elsewhere, too. By understanding how our planet became habitable, we might understand how other planets could support life.

Now researchers have made a step towards getting an answer, by ruling out one of the most common explanations: that water made it here by coming from meteorites.

Scientists analysed meteorites that had been floating in space since the solar system formed some 4.5 billion years ago.

They found that they had extremely low water content – so dry, in fact, that they had less water than almost anything ever studied in space.

“We wanted to understand how our planet managed to get water because it’s not completely obvious,” said University of Maryland Assistant Professor of Geology Megan Newcombe. “Getting water and having surface oceans on a planet that is small and relatively near the sun is a challenge.”

The findings are reported in a new study, ‘Degassing of early-formed planetesimals restricted water delivery to Earth’, published in Nature.