Scientists from the Natural History Museum in London have confirmed the discovery of a meteorite within twelve hours of a fireball meteor (defined as a meteor brighter than the planet Venus) being seen over England. The fireball was seen over the West Midlands region of England slightly before 10.00 pm GMT on Sunday 28 February 2021, and within a few hours a resident of the village of Winchcombe in Gloucestershire had reported finding a chunk of meteorite on their driveway.
The meteorite is described as soft to the touch, and is of a type known as a carbonaceous chondrite. Such meteorites are rich in clay minerals (implying the freezing of water within the rock at some point in their history), and are much rarer than stoney (generally basaltic) or iron meteorites, largely because they tend not to survive the journey through the Earth's atmosphere, however similar material has been recovered from asteroid 162173 Ryugu by the Hayabusa2 space probe, and from asteroid 101955 Bennu by the OSIRIS-REx space probe, implying that carbonaceous chondrite material may be more common in the Solar System than on Earth.
The fact that the Winchcombe Meteorite made it to the ground at all implies that the body which produced it was travelling relatively slowly compared to the Earth; most meteors hit the atmosphere at about 70 km per second, which means that material, particularly soft material, from them has little chance of reaching the ground intact. However, if a body is travelling on a trajectory similar to that of the Earth, it may intersect the atmosphere at a much lower speed, making it much more likely that some of it will reach the ground.
This makes the Winchcombe Meteorite special for several reasons. Carbonaceous chondrites are rare, and yield much more information about the early Solar System than iron or basaltic meteorites, as they frequently contain organic molecules, important for our understanding of the emergence of life. Such meteorites seldom make it through the atmosphere intact, and those that do need to be recovered quickly, as their soft nature means that they are quickly altered and eroded by Earth's atmosphere and moisture. Moreover, meteorites connected to observed meteors are also rare, and can tell us more about their origin than a meteorite found, for example, on top of an Antarctic glacier, which might have sat there for hundreds of years before being discovered. About 90 000 meteorites are known in museum collections around the world only 51 are carbonaceous chondrites that can be linked to meteor observations. Because the Winchcombe Meteorite was observed not only by a large number of Human observers, but by a large number of fixed cameras, it is highly likely that scientists will be able to reconstruct its original trajectory, and determine where abouts in the Solar System it came from.
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