Diamonds in desert asteroid point to long-lost planet
- Author: Joe Gonzales Apr 19, 2018,
Apr 19, 2018, 1:44
Therefore, the Almahata Sitta meteorites finally confirm the existence of large proto-planetary bodies, which had only been speculated until now.
This meteorite named Almahata Sitta belongs to a class of rocks known as Ureilites - parts of a giant planet which is believed to have been catastrophically destroyed by a collision before the birth of our solar system. And what's even cooler than finding space diamonds?
"This is the first compelling evidence for such a large body that has since disappeared", said the authors of a new study, published Tuesday in the journal Nature Communications. Second, the flecks of diamonds inside the rocky meteorite were much larger than those often found in other space rocks.
The Swiss institute called it a planetary "embryo" - a proto-planet that was created in the early chaotic days when the solar system was just starting out, and that got torn apart by cosmic collisions some 4.5 billion years ago.
"We didn't expect to see these inclusions at all", he said.
Almahata Sitta was found by an automated telescope atop Mount Lemmon in Arizona, in October 2008. They are partly differentiated - not made of the primitive material that constituted the solar nebula, but also not as well mixed and baked as rocks that come from modern planets.
According to the researchers, this means the diamonds formed at the extreme pressure of 20 gigapascals, about 180 times as crushing as the pressure found at the bottom of the Mariana Trench, the deepest point in Earth's oceans.
The diamonds we're familiar with are formed when sheets of carbon called graphite - the same material in pencil lead - is squeezed to incredible pressures. Upon further inspection the team noticed that the diamonds were far from crystal clear. However, scientists chose to volunteer and search for fragments that came from the asteroid, and they were able to collect more than 600 pieces of the meteorite. He laughed. "And indeed they did". The analysis of the data showed that the diamonds had chromite, phosphate, and iron-nickel sulfides embedded in them - what scientists refer to as "inclusions". The study shows that the parent body from which the meteorite came was a planetary embryo of a size between Mercury to Mars.
Whatever happened to this lost world? The space rock, now dubbed 2008 TC3, didn't leave any damage but the fragments that fell on the ground after that explosion could be the key to understanding the history of our solar system, particularly planets that faded away with time. He plans to seek out similar meteorites and search them for inclusions that might provide clues about their origins.