Scientists have confirmed that extraterrestrial water was first found in a British meteorite and looks a lot like Earth’s oceans.
The Winchcombe meteorite landed on a driveway in Gloucestershire in February last year and was found so soon after the impact that researchers believe it is one of the most pristine ever discovered.
The piece of space rock came from the asteroid belt between Jupiter and Mars and crucially contains significant amounts of water that closely match that on Earth, as well as amino acids – important building blocks of life.
Many scientists believe that life began on Earth following the bombardment of asteroids or comets containing life-giving ingredients. But most of those that have been studied contain water that has a different composition than that found on our planet.
The new research shows that the Winchcombe meteorite is composed of water very close to that of Earth’s oceans, suggesting that life has been seeded on our planet by rocks that float closer to home.
Often contaminated meteorites after landing
Dr Ashley King, of the NHM’s Planetary Materials Group and UK Fireball Alliance, told delegates at the British Science Festival in Leicester: “What’s really exciting for us is that the Winchcombe meteorite was collected around 12 hours. after landing, so the water that’s in the rock hasn’t been contaminated with the water we have in our atmosphere, so it’s basically very cool.
“We can be really sure when we measure water that is extraterrestrial water. The composition of that water is very very similar to the composition of water in Earth’s oceans.
“So it’s really good proof that asteroids and bodies like Winchcombe were making really important contributions to Earth’s oceans.
“It also has 2% carbon, and a significant fraction of this is made up of organic materials, such as amino acids. If you want to start making DNA and stuff, you need amino acids, so all these starting materials are locked up in the Winchcombe meteorite. “
Although other meteorites have been found containing water that resembles water on Earth, scientists were never sure if they collected it while lying down after landing.
Meteorites are usually not found for long after landing, leading to contamination.
The Winchcombe meteorite was originally part of a larger carbonaceous asteroid, formed about 4.6 billion years ago, from the building material of the remaining planet from the early Solar System.
But after one piece was detached, it took about 300,000 years to reach Earth, according to scientists. It contains about 12% water, which is encased in minerals in a kind of mud.
Dr. King added: “We think the Earth formed dry and you need water to start having atmospheres and start having life and all.
“So one of the big questions we have in planetary science is where does water come from? Were comets the main source, asteroids the main source?
“The composition of the water on the comets, at least some we have visited, doesn’t quite match the oceans on Earth, but the composition of the water in the Winchcombe meteorite is much better. So this would imply that carbonaceous asteroids were probably the main source of water for the Earth. “
The initial remains of the meteorite were found by the Wilcox family, and other fragments were found by meteorite hunters in the following month.
It was the first to be found in Britain since 1991 and the fragments are now on display in the Natural History Museum.
A meteor seen this week in the skies of Scotland and Northern Ireland is believed to have fallen into the Atlantic near the Hebrides.