How Scientists Found Rare Fireball Meteorite Pieces on a Driveway — and What They Could Teach us

Monica Grady, Professor of Planetary and Space Sciences in the Open University, related who on February 28th at 21:54 GMT, around the time of the late evening news in the UK, a different news story emerged in the night sky – a sizeable and radiant fireball visible in southern England and northern France. The incident was captured not only by several doorbell webcams but also by the automated cameras of the UK Meteor Observation Network and similar networks, making it a well-observed fireball.

The meteor-watchers, working with colleagues in France and Australia, determined the fireball’s trajectory and narrowed down the possible location of the meteorite pieces to just north of Cheltenham in the UK.

While examining the photographs he received, one, in particular, stood out: a small pile of dust and pebbles on a driveway in the tiny village of Winchcombe. Richard Greenwood, Open University researcher, was asked by King to check the sample since he lived the closest. The sample was a meteorite of a very rare species, much to Greenwood’s astoundment, which was fortunate for the UK since this meant a new addition to the meteorite collection.

Specialist researchers from several UK institutions systematically searched the surrounding Winchcombe in teams for the following four days. As a result, several stones weighing around 500g, a hefty amount of dust, and fragments were found and are now at the Natural History Museum.

Precious rocks

Why is this important? Meteorites are categorized into two groups: primitive or processed. The primitive ones preserve the composition of the solar nebular that birthed the Solar System. It is also where they are from, while the processed ones come from larger bodies, contain information about planetary surfaces and interiors, and were altered by heat.

The collected stones are carbonaceous chondrites, a sub-category of primitive meteorites considered the most pristine (or unchanged) of all meteorites. They are rich in organic compounds – the molecules that form the building blocks of life- containing tiny particles of dust from stars that have died, and are older than the Sun, carrying evidence of the earliest stages of Solar System history.

The newfound rocks have their differences; some are dark grey with irregular, pale patches, while others are almost completely black and featureless. The complexity of the meteorite suggests that it came from the surface of an asteroid where several different bits of it got mixed up during collisions.

Presently, scientists are collecting samples from two asteroids in space. The first is a sample of approximately five grams collected from the asteroid Ryugu by the Japanese Hayabusa2 mission that arrived safely in December 2020. The other is a sample of approximately 200g collected from the asteroid Bennu by Nasa’s OSIRIS-Rex mission. It is already on its return trip and is expected to arrive in September 2023. The mysteries of the origins of life and the Solar System could be unveiled with the help of these missions; however, they are extremely expensive. Moreover, ironically, almost 500g of rock from an asteroid, possibly very similar to Ryugu and Bennu, falls over part of England seemingly out of nowhere.

Next steps

Now, the material will be analyzed practically on a grain-by-grain basis by meteoriticists in the UK. Around the first month or so of a fresh fall, things must happen in a sequence, given that there are time-sensitive measurements to carry out during that frame of time. Despite not being radioactive – do not emit harmful radiation – meteorites contain unstable elements and fall apart. By measuring the amounts of the elements that degrade, the fastest valuable information can be attained.

The Earth itself poses a risk of contamination to the meteorite, especially regarding the organic compounds of its composition, meaning that these compounds in the meteorite should be analyzed as promptly as possible. Understanding more about these materials in meteorites means

being closer to piece together the chemistry that led to life on Earth, allowing a better understanding of how common that chemistry might be (or have been) in the Solar System, or even the universe.

Usually, searching for a meteorite in a small village and its surrounding fields is not hazardous and requires little risk assessment: ask permission of the owners to access their land, observe the country code, remember to close gates, and do not tread in anything soft. However, everything changes amid a pandemic.

Currently, the UK government forbids citizens from traveling far from home except when it is essential, as it was for the group of meteoriticists to travel to Winchcombe. With completed fieldwork risk assessments and permission to travel from their institutions, each meteoriticist traveled and meticulously wore a mask while maintaining a 2m distance when talking to locals.

Grady expressed her interest to participate in the search; however, upon hearing the account of her colleague Sara Russel, reporting how strenuous cleaning a driveway with a toothbrush was after the first hour, she admitted it would be impossible with her arthritic knees. During the sample collection, Grady was at the base putting machinery in motion to get the risk-assessment paperwork for Greenwood sorted, a task equally important. As a reward, Grady saw the first close-up photographs of the new family member, dubbed “Winchcombe,” which resembled a broken barbecue briquette but was absolutely beautiful in her opinion.

This article is republished from The Conversation under a Creative Commons license. Read the original article.