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How did life spawn on Earth? This meteorite might know the answer

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Jul 28, 2021, 2:08 PM EDT

Space rocks are so common, you can even find them on eBay, but some meteorites that fall to Earth are invaluable. An eerie greenish-yellow fireball streaked across the sky one night back in February.

Almost certain it was a meteorite and eager to find out where it would crash, analytical chemist Derek Robson and his research team of the East Anglian Astrophysical Research Organization (EAARO) drove out to see if they could find any surviving pieces. Thousands of minor meteors never make it to Earth because they burn up in the atmosphere before they have the chance. 

The researchers weren't sure they would find anything. After no fragments turned up, they left the site behind just as another meteor blazed through the atmosphere. It was as if it was an omen to return. Fast-forward a month and they were back at the same site, searching through the mud for any signs of a meteorite. This time, something surfaced.

Credit: Derek Robson / EAARO

What Robson saw at his feet was a small crater in which was embedded a piece of rock with a telltale iridescence, shifting colors in the sunlight. They knew they had found what they were looking for but had no idea what it was made of. When they took it back to the lab for testing, they realized just how much it stood out. This meteorite had shot at least 110 million miles through space from the asteroid belt, somewhere between the orbits of Mars and Jupiter. It also had a distinctive smell that gave away volatile (easily evaporating) organics that could tell the team where it came from.

This meteorite was hiding something else. It had an unusual composition unlike anything else they—or anyone else—had ever seen. Though much about it is still unknown, that could mean that its chemistry, physical structure or both are something entirely alien to us.

Credit: EAARO

There are many different types of asteroids, with varying compositions, floating around in the asteroid belt. Some formed close to where they are orbiting now. Others emerged from the edge of the solar system and carried water and frozen carbon dioxide with them. Some meteorites that have landed on Earth were found to have traces of these substances, meaning that our own water may have come from somewhere nowhere near the one planet in the universe we know of that can support life. The asteroid Robson found was like a cosmic time capsule: a rare form of carbonaceous chondrite.

Credit: EAARO

 

Carbonaceous chondrites encompass some of the most primitive meteorites that exist. They are made mostly of olivine and pyroxene and full of tiny spherical embeds, or chondrules, of minerals, but also tend to have high levels of carbon. While carbon itself isn't necessarily organic, the carbon found in certain carbonaceous chondrites has proven to be attached to complex organic molecules such as amino acids. DNA is made of proteins that are sequences of amino acids. It is possible that meteorites like this one could have transported the necessary ingredients for life to Earth. 

Credit: EAARO

The scientists subjected the rock to almost every test imaginable, from X-ray diffraction to vibrational spectroscopy, which studies how atoms in a molecule move. It was observed on a micro and nano scale. What they found was nothing short of incredible. This meteorite had remained pristine for billions of years. Most debris from space that ends up on Earth has taken a beating. When the solar system was still forming, things were constantly crashing into each other, sometimes so hard that pieces of one object would transfer to another or melt into another surface from the heat of an impact.

What else will this meteorite reveal? Whether or not it discloses the secrets of life, there is bound to be something in this deceptively unimpressive piece of rock that will make time travel possible.