On the night of February 28, a rocky shard fell from the sky, illuminating the atmosphere over England. The impressive fireball was captured by an international network of meteorite-tracking cameras, and scientists were sent to the sleepy town of Winchcombe. One chunk of the meteorite was found in a driveway, while another was found in a field full of sheep poo.
About 18 ounces of space rock have been found so far, all of which has been promptly delivered to a select number of scientific institutions – primarily the Natural History Museum in London – for preliminary analysis. Fast transporting the samples to the laboratories was critical to ensure that the Earth’s environment did not significantly alter the chemistry of these near-pristine materials from space.
As it turns out, the meteorite – the first found in the UK in 30 years – is a fairly rare type known as a carbonaceous chondrite. These ancient fragments contain not only the building blocks of planets, but also compounds that can help explain how the Earth got its water or even provide clues as to how life itself originated.
“This is like the magical type of meteorite that many people are completely fascinated by,” said Katherine Joy, a meteorite expert at the University of Manchester.
Oddly, the meteorite’s chemistry, minerals, and textures do not appear at first glance to belong to any particular type of carbonaceous chondrite. Each of the fragments studied so far appears to be slightly different from the others.
“Could it be a new meteorite type, a new meteorite class, something we’ve never seen before?” asks Luke Daly, a meteorite expert at the University of Glasgow. It’s an intriguing possibility, but it takes additional research to say one way or another.
Scientific work on what will likely become known as the Winchcombe Meteorite has only just begun. But the meteorite’s rarity, combined with the speed with which it was recovered, has exploded the meteorite community with cheers.
“We’ve all just gone banana,” said Sara Russell, a planetary scientist at the Natural History Museum in London. “For our meteorite group it is the most important acquisition, I would ever say.”
Time capsules from above
Meteorites strike Earth all the time, but most of them are not big enough to announce themselves with a fireball. Even when they do, many of them fall into the oceans. The vast majority of collected meteorites are found in deserts, particularly the cold Antarctic desert, a vast expanse where conveyor-like ice flows deposit space debris in specific areas, and the continent’s white hues make black meteorites easily stand out.
The UK is small, so meteorites don’t often fall on the islands, and it’s full of cities and vegetation, making meteorites difficult to find. But occasionally space rocks just happen to fall right in front of people. On Christmas Eve 1964, a meteorite “bounced off a driveway, through someone’s window and landed under their Christmas tree,” said Matthew Genge, a meteorite expert at Imperial College London.
In recent years, meteorite hunters in the UK have increased their chances by setting up cameras designed to spy on fireballs, which are used to find out where the fragments fall to Earth. Over the past decade, six different networks of sky-facing cameras, operated by both amateur and professional researchers, have been integrated into the UK Fireball Alliance.
These cameras “point at the sky all the time,” always recording and looking for striking flashes or objects shooting through the sky, said Jim Rowe, the group’s organizer. During the pandemic, he wrote computer code that allowed these individual networks to communicate with each other to track objects falling from above.
The system has occasionally caught fireballs for the past five years, but the impact locations were not convenient for collecting. A few years ago, “there was a fireball that dropped a meteorite directly into the North Sea,” says Daly, missing the surrounding countries of the UK, Northern Europe or Norway where it could have been found.
Welcome to Winchcombe
In late February, after years of watching and waiting, a six-second fireball was caught throwing meteorite fragments through Gloucestershire, a county in southwest England. The trajectory was immediately analyzed by a team of international researchers working with the UK Fireball Alliance, the likely impact zone was determined and experts from all over England descended on the town of Winchcombe and the surrounding region.
After a few days of looking around, scientists alerted the local press and asked the public to help them find strange-looking rock fragments. People from all over the country sent experts numerous photos of possible fragments.
A family woke up to find black rock fragments and sooty splashes in their driveway. After hearing reports of a fireball, they soon learned that the debris was a meteorite and contacted the British Meteor Observation Network. Just 12 hours after impact, much of the meteorite had already been bagged, ready to be collected by the experts.
“How generous to recognize how important this is to science and to want to contribute to it,” says Joy.
Daly and his girlfriend Mira Ihasz joined a group who combed through a nearby field full of sheep poo. As a rock shoots through Earth’s atmosphere, material melts and hardens into a black shell, and the dark hues of the sheep dung uncomfortably resembled the scorched crust of meteorites.
“Another promising shit, as we began to call it,” said Daly. But after that five days of searching, Ihasz stumbled upon the real deal
The chunk was found within 400 feet of where the models said fragments should have landed – a remarkable degree of accuracy, but not precise enough for the modellers, who expressed some disappointment, according to Daly, that their prediction was not more accurate.
‘A mud ball from the start’
Preliminary work indicated that the meteorite was a carbonaceous chondrite – rocky objects as old as the solar system named for their carbon-rich compositions. Such space rocks are rare. Of the 65,209 cataloged meteorites, only 2,639 are carbonaceous chondrites.
The exact origin of most meteorites remains a mystery. But thanks to the Winchcombe meteorite’s well-documented terrestrial trajectory, it was traced back to the outer edge of the asteroid belt, between Mars and Jupiter.
“Knowing where this thing came from and what it is is really special,” says Joy. This knowledge makes it easier to figure out what type of asteroid the meteorite came from, and it also helps scientists better understand the types of perturbations in space that can send rocks our way.
Although the Winchcombe meteorite shows features of multiple types of carbonaceous chondrites, meaning this could be something completely new, it was identified as a CM type in the first chemical analysis. These meteorites contain (among other things) abundant water-bearing minerals.
“It’s been a mud ball from the start,” said Genge of Imperial College London. Only 652 of them have ever been found.
Compared to most other types of meteorites, CM chondrites are “incredibly delicate,” says Daly. The minerals inside are broken down quickly in Earth’s wet atmosphere, so when exposed to the elements for a long time, “these things just turn to dust.”
“The fact that it is so fragile and delicate, and the fact that it was retrieved so quickly, was critical,” says Joy. “This one was packed up and back at the museum within 36, 48 hours after it fell, which just doesn’t happen that often.” The rapid recovery means that the ingredients have been preserved almost perfectly – and they will reveal a lot about the early solar system and the lush planet we live on today.
Secrets of Earth and Space
A secret hidden in rocks like the Winchcombe meteorite has to do with how Earth got such massive amounts of water. The gigantic impact on our planet that led to the formation of the moon some 4.5 billion years ago probably took away much of the water that Earth began with.
Whether the surface water we have today mainly came from within the planet and escaped through volcanic eruptions, or whether it was mainly delivered by swampy asteroids is a matter of debate. By studying the hydrated minerals in carbonaceous chondrites, Russell says, we can discover what process filled the oceans of our modern world.
CM chondrites also generally contain many different organic molecules, including amino acids and sugars, and this meteorite is not expected to be any different. Asteroids bombarding early Earth are said to have brought with them this organic matter, perhaps the materials needed to form the first living organisms.
“That organic chemistry may have accelerated the origin of life on Earth,” says Genge.
Meteorites can also tell us about the time before the Earth formed. The Winchcombe Meteorite contains properties known as Calcium Aluminum Rich Inclusions or CAIs. “They are the oldest solids in the solar system, which is of course the most amazing, cool thing,” says Russell.
The chemistry of CAIs suggests that they all formed at the same time and place, 4.56 billion years ago, right next to the sun, before becoming trapped in rocky material that clumped together in the cold reaches of the outer solar system. The dramatic journey out of this material is not easy to explain, but collecting more CAIs will help unravel how matter moved and mixed as planets formed and the solar system evolved into its modern form.
CM chondrites also often contain substances such as graphite and diamond grains that are, quite remarkably, older than the solar system itself. Their chemistry is so different from anything found in our solar system that scientists believe they came from the atmosphere of giant stars or formed by supernova explosions before drifting into our still-forming cosmic environment.
Such grains were “blown into the universe, floated around for hundreds of millions of years, and then collapsed inward to form our solar system,” says Genge. While these primal gems have not yet been identified in the Winchcombe meteorite, scientists fully expect it, like other CM chondrites, to contain grains predating the solar system.
The Winchcombe meteorite could therefore hold clues not only to the history of our neighborhood around the sun, but also to the ghosts of other planetary systems that have been lost over time – and the international effort to decipher its many secrets is just started.