Scientists Have Just Worked Out Where Earth’s Water Came From

Most of our planet is covered in water - but scientists have been unsure where it all came from.

Many have believed that it arrived after our planet formed - carried by comets or meteorites.

But the answer seems to a bit odder: it arrived in the form of a frozen dust from space, as the solar system formed from a ‘planetary disk’

Scientists at the University of Hawaii at Manoa have found evidence that our planet’s water was here from the beginning.

The researchers studied rocks on Baffin Island, Canada.

The rocks have tiny amounts of water within them - untouched for millions of years - and the researchers found that the ratios of two types of hydrogen (hydrogen and deuterium) showed that the water had been on Earth since it formed.

Dr. Lydia Hallis of the University of Glasgow said, ‘The Baffin Isand rocks were collected back in 1985, and scientists have had a lot of time to analyze them in the intervening years. As a result of their efforts, we know that they contain a component from Earth’s deep mantle.

‘On their way to the surface, these rocks were never affected by sedimentary input from crustal rocks, and previous research shows their source region has remained untouched since Earth’s formation. Essentially, they are some of the most primitive rocks we’ve ever found on Earth’s surface, and so the water they contain gives us an invaluable insight into Earth’s early history and where its water came from.

‘We found that the water had very little deuterium, which strongly suggests that it was not carried to Earth after it had formed and cooled. Instead, water molecules were likely carried on the dust that existed in a disk around our Sun before the planets formed. Over time this water-rich dust was slowly drawn together to form our planet.’

‘Even though a good deal of water would have been lost at the surface through evaporation in the heat of the formation process, enough survived to form the world’s water.

“It’s an exciting discovery, and one which we simply didn’t have the technology to make just a few years ago. We’re looking forward to further research in this area in the future.’