The space rock that hit a town in England last year contains water similar to our planet’s oceans.
A meteorite that landed in Winkcombe in south-east England last year contained almost as much water as Earth.
This reinforces the idea that rocks from space could have brought important chemical components, including water, to our planet early in its history, billions of years ago.
This meteorite is considered the most important meteorite ever recovered in the United Kingdom.
The scientists, who have just published their first detailed analysis, say the body has yielded fascinating information.
More than 500g of dark debris has been collected from residential gardens, sidewalks and fields after a giant fireball lit up the nighttime sky over Winkcombe.
The fragmentary remains were carefully cataloged at London’s Natural History Museum, then loaned to teams across Europe for investigation.
Water accounts for up to 11% of the meteorite’s weight? It contained a very similar ratio of hydrogen atoms to water on Earth.
Some scientists say that the young Earth was so hot that it would have expelled much of its volatile content, including water.
The fact that the Earth has a lot of water today? 70% of its surface is covered by oceans? It is suggested that there should be a later addition.
Some claim that this may be from bombardment by icy comets? But their chemical composition doesn’t match very much.
But carbonaceous chondrites? Meteorites like Winchcombe? Definitely coincide.
And the fact that it was recovered less than 12 hours after it fell means that it absorbed very little of the Earth’s water, or even any pollutants.
“All the other meteorites were compromised in some way by Earth’s environment,” Ashley King, lead co-author of the study, from the Natural History Museum in London, tells BBC News.
“But Winchcombe is different because of the speed at which it was captured.”
“This means that when we analyze (the meteorite) we know that the composition we’re looking at takes us back to a formation in the early solar system, 4.6 billion years ago.”
“Aside from sampling rocks from an asteroid with a spacecraft, we couldn’t get a more pure sample.”
accurate path
Scientists who examined meteorite carbon and nitrogen-containing organic compounds, including amino acids, got an equally clear picture.
It’s the kind of chemistry that could be the raw material for biology to begin with on Earth.
The new analysis also confirms the meteorite’s origin.
Video footage of the fireball allowed the researchers to determine a very precise trajectory.
A retrospective calculation indicates that the meteor came from the outer part of the asteroid belt between Mars and Jupiter.
Further research reveals that it broke off the top of a larger asteroid possibly due to a collision.
After that, it only took between 200,000 and 300,000 years to reach Earth, as evidenced by the number of specific atoms, such as neon, created in the meteorite material by the continuous radiation of high-speed space particles, or cosmic rays.
“0.2 to 0.3 million years seems like a long time – but from a geological point of view it’s actually quite fast,” explains Helena Bates of the Natural History Museum in London.
“Carbonaceous chondrites have to get here quickly or they won’t survive, because they’re so fragile, so brittle that they fall apart.”
More secrets
The scientists’ first analysis, published in this week’s issue of Science Advances, is just an overview of the properties of the Winchcombe meteorite.
Dozens more articles on more specific topics should be published soon in an issue of Meteoritics & Planetary Science.
And it shouldn’t stop there.
“Researchers will continue to study this sample for years to come, to uncover more secrets about the origins of our solar system,” said co-author Luke Daly of the University of Glasgow in Scotland.
– This text was published in https://www.bbc.com/portuguese/geral-63669358
