Extra-terrestrial water has been discovered for the first time in a meteorite that landed in the UK.
The meteorite crashed into a driveway in the Gloucestershire town of Winchcombe last February and is believed to hold clues about where the water in the Earth’s vast oceans came from.
Some 12% of the sample was made up of water, and offers a lot of insights since it was the least contaminated specimen to be collected, according to Ashley King, a researcher in the planetary materials group at the Natural History Museum.
“The composition of that water is very, very similar to the composition of water in the Earth’s oceans,” he told the British Science Festival.
“It’s a really good piece of evidence that asteroids and bodies like Winchcombe made a very important contribution to the Earth’s oceans.”
Dr King also confirmed that it was the first time a meteorite containing extra-terrestrial water – albeit locked up in minerals – had fallen in the UK, in the historic Cotswold town.
He explained that because the 1lb (0.5kg) meteorite was retrieved quickly, within around 12 hours, it was not contaminated by water and materials on Earth.
He continued: “We always try and match the composition of the water meteorites and other extra-terrestrial materials to the composition of the water on the Earth.
“For most meteorites, the challenge we have is that they are just contaminated, whereas with Winchcombe we really know that it really hasn’t been contaminated, so it’s good evidence.”
Dr King went on: “One of the big questions we have in planetary sciences is where did the water on Earth come from? And one of the obvious places is either through comets that have loads and loads of ice in them, or asteroids.
“There’s always a debate – were comets the main source, were asteroids the main source?”
But he explained that data from missions to comets suggest they are not a good match for the water on earth, adding: “The composition of the water in Winchcombe is a much better match, so that would imply that asteroids – carbonaceous asteroids – were probably the main source of water to the inner solar system, to the Earth.”
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Dr King continued: “We’ve had a hint that some asteroids match back nicely to the Earth.
“But now we have a meteorite which is really fresh that we know hasn’t been modified, and it’s confirming that same story.”
Speaking at De Montfort University, which is hosting the festival, Dr King revealed that analysis suggests that the meteorite derived from an asteroid somewhere near Jupiter.
It is believed to have been formed around 4.6 billion years ago and has taken some 300,000 years to reach Earth.
As it stands, there are approximately 65,000 known meteorites on Earth.
The meteorite found in Winchcombe is the first known carbonaceous chondrite to have been found in the UK, and the first to be recovered across the country in 30 years.