4.6 billion-year-old meteorite that crashed into Earth solves the mystery of water on our planet

The ratio of hydrogen isotopes in meteorite's water resembles the composition of water on Earth.
Deena Theresa
The Winchcombe meteorite.
The Winchcombe meteorite.

Natural History Museum 

In February 2021, a rare carbonaceous meteorite crashed into a driveway in Gloucestershire. Called Winchcombe, the meteorite was recovered only hours after its fireball lit up the skies over the UK. 

A year later, experts from the Natural History Museum and the University of Glasgow have reported that the 4.6-billion-year-old meteorite has been found to contain extra-terrestrial water - providing solid evidence that water on Earth can be traced to asteroids in the outer solar system. The results are published in Science Advances.

Researchers were able to quickly recover the meteorite, thanks to public reports and video footage of the fireball captured by 16 cameras coordinated by the UK Fireball Alliance.

4.6 billion-year-old meteorite that crashed into Earth solves the mystery of water on our planet
A fragment of the Winchcombe meteorite.

Winchcombe contained 11 percent extra-terrestrial water

"The rapid retrieval and curation of Winchcombe make it one of the most pristine meteorites available for analysis, offering scientists a tantalizing glimpse back through time to the original composition of the solar system 4.6-billion-years-ago," Dr. Ashley King of the Natural History Museum and author on the paper, said in a statement.

Winchcombe is a rare CM carbonaceous chondrite containing two percent carbon and is the first ever meteorite of this type to be found in the UK. 

The team carried out detailed imaging and chemical analyses and found that Winchcombe contained approximately 11 percent extra-terrestrial water by weight. Most of it is in minerals that formed during chemical reactions between fluids and rocks on its parent asteroid in the earliest stages of the solar system, as per the release.

When the team measured the ratio of hydrogen isotopes in the water, they found it to closely resemble the composition of water on Earth. Fragments of the meteorite also contained extra-terrestrial amino acids – prebiotic molecules - essential for the origin of life. 

The meteorite provides the strongest link yet between carbonaceous meteorites and asteroids

These results highlighted that "carbonaceous asteroids played a key role in delivering the ingredients needed to kickstart oceans and life on the early Earth".

The team also discovered that Winchombe was blasted off the surface of an asteroid near Jupiter and then traveled to Earth within the last million years.

"One of the biggest questions asked of the scientific community is how did we get here? This analysis on the Winchcombe meteorite gives insight into how the Earth came to have water – the source of so much life," said Dr. Luke Daly, a lecturer in Planetary Geoscience at the University of Glasgow and author of the paper. "Researchers will continue to work on this specimen for years to come, unlocking more secrets into the origins of our solar system."

Study Abstract:

Direct links between carbonaceous chondrites and their parent bodies in the solar system are rare. The Winchcombe meteorite is the most accurately recorded carbonaceous chondrite fall. Its pre-atmospheric orbit and cosmic-ray exposure age confirm that it arrived on Earth shortly after ejection from a primitive asteroid. Recovered only hours after falling, the composition of the Winchcombe meteorite is largely unmodified by the terrestrial environment. It contains abundant hydrated silicates formed during fluid-rock reactions, and carbon- and nitrogen-bearing organic matter including soluble protein amino acids. The near-pristine hydrogen isotopic composition of the Winchcombe meteorite is comparable to the terrestrial hydrosphere, providing further evidence that volatile-rich carbonaceous asteroids played an important role in the origin of Earth’s water.

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