Extra-terrestrial water has been found in a British meteorite for the first time - and it closely resembles Earth’s oceans, scientists have confirmed.
The Winchcombe meteorite landed on a driveway in Gloucestershire in February last year, and was found so soon after impact that researchers believe it is one of the most pristine ever discovered.
The chunk of space rock came from the asteroid belt between Jupiter and Mars, and crucially contains significant amounts of water which match closely to that on Earth, as well as amino acids - important building blocks of life.
Many scientists believe that life began on Earth following bombardment by asteroids or comets containing life-giving ingredients. But most that have been studied contain water that is a different composition to that found on our planet.
The new research shows that the Winchcombe meteorite is comprised of water that is very close to that in Earth’s oceans, suggesting that life was seeded on our planet by meteorite strikes.
Meteorites often contaminated after landing
Dr Ashley King, of the Planetary Materials Group at NHM and the UK Fireball Alliance, told delegates at the British Science Festival in Leicester: “What's really exciting for us for us is that Winchcombe meteorite was collected about 12 hours after landing, so the water that's in the rock hasn't been contaminated with the water that we have in our atmosphere. So it's basically really fresh.
“We can be really confident when we measure the water that it is extra-terrestrial water. The composition of that water is very very similar to the composition of the water in the Earth’s oceans.
“So it’s a really good piece of evidence that asteroids and bodies like Winchcombe were delivering really important contributions to the Earth’s oceans.
“It’s also got two per cent carbon, and a significant fraction of that is organic materials, like amino acids. If you want to start making DNA and stuff, you need amino acids, so all of these starting materials are locked up in the Winchcombe meteorite.”
Although other meteorites have been found containing water that resembles water on Earth, scientists had never been sure whether they had picked it up while lying around after landing.
Usually meteorites are not found for a long time after they land, leading to contamination.
The Winchcombe meteorite was originally part of a larger carbonaceous asteroid, which formed around 4.6 billion years ago, from the leftover planet building material of the early Solar System.
But after a chunk was knocked off, it took around 300,000 years to reach Earth, scientists believe. It contains around 12 per cent water, which is locked up in minerals in a kind of mud.
Dr King added: “We think that the Earth formed dry, and you need water to start having atmospheres and start having life and everything.
“So one of the big questions we have in planetary science is where does the water come from? Were comets the main source, were asteroids the main source?
“The composition of water on comets, at least a few that we visited, doesn't really match the Earth's oceans, but the composition of the water in the Winchcombe meteorite is a much better match. So that would imply that carbonaceous asteroids were probably the main source of water for Earth.”
Initial remains of the meteorite were found by the Wilcox family, and further fragments were found by meteorite hunters in the following month.
It was the first to be found in Britain since 1991, and fragments are now on display at the Natural History Museum.
A meteor spotted this week over the skies of Scotland and Northern Ireland is believed to have fallen in the Atlantic, near the Hebrides.