Scientists have analyzed diamonds found in a meteorite that crashed on Earth a decade ago. They were able to demonstrate that the origin of the diamonds wasn't a result of the impact but that the growth took place inside of a planet.
An ancient planet may have aged long enough to form diamonds but not survive the tumultuous period during the formation of the solar system.
Diamonds From Another Planet
A meteorite crashed into the Nubian desert of Sudan in 2008. This was the first time that a team of scientists tracked an asteroid that became a meteor. Students from the University of Khartoum recovered more than 600 pieces of the meteorite. The meteorite was then named the Almahata Sitta.
Researchers from Switzerland, France, and Germany published a study in the journal Nature Communications showing that the Almahata Sitta contained tiny diamonds inside it. They also determined that the diamonds were formed on a protoplanet during the formation of the solar system at least 4.55 billion years ago.
Scientists determined that the pressure needed to form the diamonds would have to have taken place inside of a planet. They calculated that there would need to be a pressure of 200,000 bar (2.9 million psi). This calculation suggests that the protoplanet may have been as large as Mercury or even Mars.
Lead author of the study Farhang Nabiei says that these materials are coming from a time that science has no access to. By examining these materials, they're able to get a picture of the early solar system. At that point, there were many more planets, and some were still forming.
Almahata Sitta is classified as ureilite. These rocks come from a time that's between the primitive material at the beginning of the solar system and the rocks that come from modern planets.
These types of rocks always have diamonds inside of them. Scientists can't trace them to a source because the planet in question no longer exists.
These diamonds may not fit a typical opinion of diamonds. They're small. The Washington Post describes them as "less than a fraction of a percentage of an inch in diameter." At first, it was believed that the diamonds formed with the shock of colliding with another body. This was disproved when the researchers noticed that the diamonds were too large to have formed that way.
Coauthor of the study Philippe Gillet says that the meteorite is a remnant of a planet that no longer exists. He describes it as the first generation of planets that were destroyed or swallowed up by a larger planet.