A Piece of Comet Has Been Discovered in the Last Space Object You'd Think to Check

Meteorites are a bit like fruitcake – chunks of mineral held together by a stone matrix. These minerals can contain some pretty fascinating glimpses into the stuff of the Solar System – but now they have never seen before.

In a meteorite recovered from Antarctica in 2002 is a tiny, ancient sliver of the building blocks of comets – encased, the researchers said, like an insect in amber.

The meteorite is called LaPaz Icefield 02342 (LAP 02342 for short), and it has a type of meteorite known as a carbonaceous chondrite.

Meteorites come in a variety of types, asteroids or even planets, and they are hurtling through space until they collide with Earth, after surviving the explosive effects of atmospheric entry.

Their composition can vary, and that is used for meteorite classification. Carbonaceous chondrites are among the most primitive, thought to originate from asteroids that formed around 4.5 billion years ago – when the Solar System was also formed – out of the orbital range of Jupiter.

Comets, too, formed from the same protoplanetary disc of dust and gas that circled the newborn Sun, but much farther away than asteroids, so their composition is different. They have a lot more water – that is what creates the famous tail when they get close to the Sun. And they have a lot more carbon.

The team was not actually looking for comet giblets. Meteorites are a lot of time capsule to the early Solar System, rich with grains presolar, and information about the heating and chemical processes present during the training system.

But comet giblets is what they got.

(Larry Nittler / Carnegie Institution for Science)

"When I saw the first electron images of the carbon-rich material," said Jemma Davidson cosmochemist of Arizona State University, "I knew we were looking for something very rare. "

That tiny carbon-rich sliver, measuring just a tenth of a millimeter, boron strong similarities to interplanetary dust particles and micrometeorites thought to originate in comets that formed in the Kuiper Belt at the outskirts of the Solar System.

The team conducted isotopic analysis of the sliver, and concludes it in the same place.

Its inclusion in a meteorite suggests that it must be migrated inwardly from this starting position, drawing slowly closer to the Sun until it reaches the region where the carbonaceous chondrites form.

Then, around 3 to 3.5 million years after the formation of the Solar System, this microscopic sliver somehow, perhaps via a collision, became incorporated into the asteroid that would fragment to produce LAP 02342.

The Solar System and the Chemistry of the Protoplanetary Disc at various distances.

"Because this sample of cometary building-block material was swallowed by an asteroid and preserved inside this meteorite, it was protected from the ravages of entering Earth's atmosphere," said cosmochemist Larry Nittler of the Carnegie Institution for Science.

"It gave us a material that would not have survived our planet's surface on its own," "Solar System's Chemistry."

The research has been published Nature Astronomy.