Guided by a team of international fireball trackers including Western’s Denis Vida, scientists recovered almost 300 grams of an extremely rare meteorite this week in Winchcombe, England – a type which has never fallen anywhere in the U.K. before.
The meteorite, likely to be known as the Winchcombe meteorite, is an extremely rare type called carbonaceous chondrite, which have been known to contain organics and amino acids – ingredients for life.
The target of an unprecedented worldwide research effort providing answers to questions about the early history of our solar system and life on Earth, the meteorite samples are now being studied by a scientific team at Natural History Museum.
Footage of the meteor from the UK Fireball Alliance and Global Meteor Network (GMN) captured on February 28, 2021 helped locate the meteorite and determine where it came from in the solar system, linking this incredible sample to its origins in space. GMN is a world-wide collaboration between professional and amateur astronomers, which operates more than 300 meteor cameras in 22 countries. The international effort is coordinated by Vida, a meteor physics postdoctoral associate at Western.
The day after the incredible event, Vida was contacted by Jim Rowe, the coordinator of the UK Fireball Alliance, to compute the trajectory of the fireball using Western’s state-of-the-art meteor trajectory software. Vida reviewed the data from the GMN cameras and identified two of the U.K.-based cameras observed the fireball.
After adding his observations, Vida confirmed the fireball ended at the height of 27 km, which strongly indicated that there were some meteorites on the ground. In fact, the GMN camera was able to track the fragments which survived the atmospheric flight down to the velocity of 3 km/s, which is the theoretical limit at which meteors slow down so much that they stop producing light. Further analysis showed that the four largest fragments visible in the video have a mass of around 100 grams.
Immediately after the fall, Ashley King from Natural History Museum was on the scene and was able to quickly locate the meteorites.
“It turned out that they were of an extremely rare meteorite type, a carbonaceous chondrite. So far, this is only the fifth meteorite of this type with a known orbit, and the most pristine one because it was recovered immediately after the fall,” said Vida.
Carbonaceous chondrites are rocks that remained in the deep freeze for the last 4.5 billion years, untouched by any heating. They are the remnants of the formation of the Solar System – the ingredients for literally everything.
“Imagine you take some eggs, flour, and sugar. You follow a recipe, mix them together and bake them in the oven. Voila, you have nice cake,” said Vida. “The cake is our Solar System. Baked, mixed, changed. In this analogy, carbonaceous chondrites are a chunky mix of eggs, flour and sugar that somehow ended up in the freezer, and we’re using them now to figure out how the cake, in this case the Solar System, was made.”
Vida says carbonaceous chondrites are also very important because they contain presolar grains, which are small dust particles even older than the Sun.
“They are rare, direct evidence that we have for liquid water outside the Earth,” said Vida. “Some contain up to 20 per cent water, and are full of organic compounds, including amino acids.”
The Western meteor group, led by Canadian Research Chair in Planetary Small Bodies Peter Brown, was involved with a recovery of a similar meteorite in 2000. A large fireball dropped meteorites over Tagish Lake in northwest British Columbia, but most of the carbonaceous chondrite meteorites fell onto a frozen lake. Due to their black surface, they heated up during the day and melted through the surface of the lake, ending up encased in ice which irreversibly damaged them.
According to Vida, recovering abundant quantities of this pristine meteorite in Winchcombe so quickly is comparable to the samples recently returned from space by the Japan Aerospace Exploration Agency (JAXA) Hayabusa2 mission.