The first evidence of extraterrestrial water has been found in a meteorite that landed in the UK.
The meteorite, which struck a driveway in the Gloucestershire village of Winchcombe in February, is believed to have clues on the origin of the water that fills the planet's immense seas.
According to Ashley King, a researcher in the planetary materials section at the Natural History Museum, the sample, which included water in proportion to around 12% of the total weight, provides a wealth of information since it was the least contaminated one ever obtained.
"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 further affirmed that the ancient Cotswold town was the site of the first meteorite to fall in the UK that contained extraterrestrial water, however, encased in minerals.
He said that since the 1lb (0.5kg) meteorite was recovered so quickly—in only 12 hours—it was unaffected by the water and other substances 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.
The problem with most meteorites is that they are just contaminated, but with Winchcombe, we are certain that it hasn't been at all, therefore this is strong proof.
Where did the water on Earth originate from is one of the major problems in planetary sciences, said Dr. King. And one of the obvious routes is either by asteroids or comets with a tonne of ice in them.
Was asteroids or comets the primary source, which is the subject of ongoing discussion?
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."
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."
Dr. King stated during a speech at the festival's host institution, De Montfort University, that examination indicates the meteorite originated from an asteroid close to Jupiter.
It is thought to have originated approximately 4.6 billion years ago and traveled to Earth over the course of around 300,000 years.
There are now over 65,000 known meteorites on Earth.
The meteorite discovered in Winchcombe is the first carbonaceous chondrite to have been discovered in the United Kingdom and the first to have been retrieved in the whole nation in the last 30 years.