Research on the first meteorite to be found on UK soil for 30 years has revealed how fast space rocks are contaminated by the Earth’s atmosphere.

The meteorite landed in Winchcombe in the Cotswolds last February with fragments recovered from a domestic driveway hours after it entered the Earth’s atmosphere.

More pieces were found in a sheep field six days later.

Analysis of the meteorite show the fragments quickly developed salts and minerals from the interaction of their surfaces with the damp environment in which they landed

The findings could help protect new meteorites after they are found.

Lead author, Laura Jenkins, a PhD student at the University of Glasgow said once meteorites are exposed to terrestrial contaminants they change.

She said: “Analysis of meteorites can provide insights into the asteroids they come from and how they have formed.

“Winchcombe and other meteorites like it contain extra-terrestrial water and organics, and the asteroids they come with may be responsible for delivering water to Earth, giving it enough water to form its distinctive oceans.

“However, when a meteorite is exposed to terrestrial contaminants, especially moisture and oxygen, it undergoes changes, affecting the information it provides.”

Researchers examined two small pieces of Winchcombe for signs of terrestrial modifications.

They used scanning electron microscopy, Raman spectroscopy and transmission electron microscopy to scrutinise the surfaces of the samples.

One sample was taken from the driveway fragments and the other from those found in the sheep field.

They found that two forms of salt - sulfates of calcium and calcite - had formed on the fusion crust of samples recovered from the sheep field.

And they found halite, also known as table salt, on the sample taken from the driveway.

The fusion crust is the distinctive material formed when meteorites melt during their fiery entry to the Earth’s atmosphere.

Researchers said since the sulfates appeared on the outside of the fusion crust, it is likely they appeared after it landed, as a result of exposure to damp conditions in the sheep field.

The halite appeared only on the surface of polished sections of the driveway fragment.

Since the polishing was done after the meteorite was recovered, it is likely that it was formed by the interaction of the rock slice with the humid laboratory air.

Ms Jenkins added: “The Winchcombe meteorite is often described as a ‘pristine’ example of a CM chondrite meteorite, and it’s already yielded remarkable insights.

“However, what we’ve shown with this study is that there’s really no such thing as pristine meteorite – terrestrial alteration begins the moment it encounters Earth’s atmosphere, and we can see it in these samples which we analysed just a couple of months after the meteorite landed.

“It shows just how reactive meteorites are to our atmosphere, and how careful we need to be about ensuring that we take this kind of terrestrial alteration into account when we analyse meteorites.

“To minimize terrestrial alteration, meteorites should be stored in inert conditions if possible.

“Understanding which phases are extra-terrestrial and which are terrestrial in meteorites like Winchcombe will not only help our understanding of their formation but will also aid in relating meteorites that have landed on Earth to samples returned by sample return missions.

“A more complete picture of the asteroids in our solar system and their role in Earth’s development can be built.

Co-author Dr Luke Daly is a lecturer at the University of Glasgow and part of the UK Fireball Alliance which spotted the Winchcombe meteorite and estimated where it landed.

Dr Daly led the search party that recovered the largest chunk of the Winchcombe meteorite from a sheep field, where it was spotted by volunteer Mira Ihasz.

He said: “We’ve always known that exposure to Earth’s atmosphere affects the surface of meteorites but this is the first time we’ve been able to see just how quickly the process can begin and advance.

“We were very lucky to be able to recover the Winchcombe meteorite so quickly through the monitoring of the UKFall network and the efforts of the volunteers who helped us recover the largest pieces from the field.

“This research shows just how vital it is that we keep watching the skies and assemble search parties as quickly as possible after meteorites are spotted.”

The paper, titled ‘Winchcombe: An Example of Rapid Terrestrial Alteration of a CM Chondrite ‘, is published in early view in Meteoritics & Planetary Science at https://onlinelibrary.wiley.com/doi/full/10.1111/maps.13949


18-year-old finds meteorite that fell to Earth hours after being discovered

An asteroid that was recently identified plummeted to the surface of Earth only hours after it was discovered, and now the meteorite has been found.











Jak Connor @JakConnorTT

Published Feb 17, 2023

European skywatchers that were lucky enough to catch a fireball lighting up the sky should know that fragments of the space rock have been found.

An asteroid estimated to be 3.2 feet in diameter was discovered by Krisztian Sarneczky, an asteroid hunter working at the Konkoly Observatory in Budapest, Hungary, who promptly gave his findings to the European Space Agency (ESA). The asteroid was confirmed, and only hours later, it began its descent to Earth over Europe, stunning at least 61 people that reported seeing its bright entry into the European night sky and its eventual disappearance after it burned out.

The fireball began falling to Earth at 10 p.m. EST on February 12 (0300 GMT February 13), and the event was captured from multiple angles. Videos show the meteor beginning to grow in brightness, eventually reaching a level of brightness that the entire night sky was illuminated before burning out. The American Meteor Society confirms sightings of the fireball from various locations across England, the Netherlands, Belgium, and France.

The discovery of the asteroid was made during a routine Near-Earth-Object (NEO) check conducted by Sarneczky. The asteroid hunter said it was immediately obvious that it was a NEO and that he noticed it wasn't moving particularly fast, but was headed straight for Earth. The asteroid was named SAR 2667 and caused the fireball event 2023 CX1.

Interestingly and luckily enough, fragments of the fireball have been recovered from SAR 2667's entry. According to reports Lois Leblanc, an 18-year-old student with the volunteer group Vigie-Ciel (rough English translation "Sky Lookout"), discovered a meteorite fragment when he noticed a dark stone that was barely level with the ground of a field, in the town Saint-Pierre-le-Viger located in the Normandy region in northern France. With the discovery of the meteorite fragment, the team of researchers plans to further inspect the area for any more pieces that may have been missed.

Coincidentally, 10 years ago, almost to the day, a meteor entered Earth's atmosphere on February 15, 2013, and exploded over Chelyabinsk, Russia. The fireball was much larger than SAR 2667, with researchers estimating it had a diameter of 59 feet. Since that fireball was much bigger than SAR 2667, it released much more energy when it exploded.

Reports indicate that the Chelyabinsk meteor released the same amount of energy as 440,000 tons of TNT exploding. The explosion generated a shockwave that blew out windows for 200 square miles, injured 1,600, and damaged 7,200 buildings.

Read more: 

https://plawiuk.blogspot.com/2023/02/meteor-filmed-exploding-above-france-as.html