A pristine chunk of space rock found just hours after colliding with Earth may tell us about the birth of the solar system

At approximately 10pm on February 28, 2021, a fireball streaked across the sky over England. The glowing extraterrestrial visitor was seen by more than 1,000 peopleand its descent was filmed by 16 cameras dedicated to tracking meteorites from the UK Fireball Alliance Y lots of dash cams and doorbell.

With the time difference with Australia, the Global Fireball Observatory The Curtin University team was the first to delve into the data from their cameras and quickly realized that there may be very special meteorites to find in the town of Winchcombe, Gloucestershire.

The news the next morning told people in the area to look for black rocks in their yard. The Wilcock family discovered a pile of dark dust and small rock pieces in their driveway. They called in specialists from the Natural History Museum who confirmed that it was a meteorite and collected the space debris for further analysis, all within 12 hours of landing.

More fragments were collected from the surrounding area over the next month. In total, the samples totaled about 600 grams of exceptionally pristine asteroid rock from the outer solar system.

We have been studying this precious find with colleagues around the world for the past 18 months. As we reported in a new role in Progress of science, it is a very fresh sample of ancient rock formed in the early years of the solar system, rich in water and organic molecules that may have been crucial in the origin of life on Earth.

How to catch a fireball

Meteors are rocks from space that have survived the fiery descent through our atmosphere. They are remnants from our (very) distant past, around the time the planets formed, that hold clues to what our solar system was like billions of years ago.

There are more than 70,000 meteorites in collections around the world. But the Winchcombe meteorite is quite special.

Why? Well, of all the meteorites that have been found, only about 50 have been seen to fall accurately enough to calculate their original orbit, the path they took to impact Earth. Figuring out the orbit is the only way to understand where a meteorite came from.

the Global Fireball Observatory is a network of cameras looking for falling meteorites. It is a collaboration of 17 partner institutions around the world, including the University of Glasgow and Imperial College in the UK. This collaboration arose from the initiative of Australia Desert Fireball Network, run by Curtin University. Of the few meteorite samples with known origins, the Fireball Global Observatory team has recovered more than 20 percent.

Winchcombe meteorite tracking

The Winchcombe meteorite was one of the best observed so far. All these observations helped us determine that this special sample came from the main asteroid belt, between Mars and Jupiter.

Observing a fireball from a network of cameras allows us to recreate the path of the rock through the atmosphere and calculate not only its orbit, but also its fall to the ground.

An illustration from Google Earth shows the estimated trajectory and landing site of the meteorite.
Observations from the fireball cameras helped scientists calculate the meteorite’s likely landing area. Richard Greenwood / Open University / Google Earth

In an email to the UK team seven hours after the fireball, my colleague Hadrien Devillepoix noted that the unusual amount of fragmentation and orbit could mean we’d be looking for a less common type of meteorite.

A space rock usually stops burning when it reaches 30 km altitude. The rest of the fall is affected by high-altitude winds, so predicting where the meteor will land is not always easy.

Curtin’s team played an important role in predicting the drop area from the fireball data. We recreated the space rock flight path to tell people where to look for meteor fragments.

Although many samples were found in the town of Winchcombe, the largest complete piece was recovered in a field during a dedicated search, found within 400 meters of the predicted position.

The building blocks of life

Winchcombe is a very rare type of meteorite called a carbonaceous chondrite. is similar to Murchison Meteorite which fell in Victoria in 1969. They contain complex carbon-based molecules called amino acids, which are considered the “building blocks of life”.

These meteorites are believed to have formed in the early solar system, billions of years ago. They formed far enough from the sun that the water had not completely evaporated, and it was close to being incorporated into these meteorites. They may have been responsible for bringing water to Earth later.

Carbonaceous chondrites are known to contain water, although most samples have been contaminated by prolonged contact with the Earth’s atmosphere. Some pieces of the Winchcombe meteorite are barely contaminated because they were recovered within hours of its fall. These samples are incredibly pristine, containing almost 11 percent water by weight.

A space rock delivered to your home

Space agencies go a long way to find space rocks this fresh. In 2020, Japan Hayabusa Mission2 delivered a few grams of material from a carbonaceous asteroid called Ryugu back to Earth. Next year, NASA OSIRIS-REx will bring home a somewhat larger part of asteroid bennu.

The speed with which samples of the Winchcombe meteorite were discovered, combined with the precise observations that made it possible to determine its original orbit in the asteroid belt, which is similar to the materials returned from space missions.

The Winchcombe fireball triangulation, orbital analysis, recovery, and geochemical techniques used to investigate the history of this space rock required a great deal of teamwork.

Along with the scientific secrets it will reveal, the story of the Winchcombe meteorite is a fantastic demonstration of the power of collaboration to unlock the mysteries of our solar system.The conversation

This article is republished from The conversation under a Creative Commons license. Read the Original article.

Image credit: Sarah McMullan / UKFN / Global Fireball Observatory

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