Last updated July 20, 2018 at 3:02 pm
Mercury-sized world was lost in space.
Credit: NASA/Bill Ingalls.
Researchers analysing diamonds in the Almahata Sitta meteorite in Sudan recently discovered that the crystalline structures held the remnants of an early proto-planet – a world that would have existed in the first 10 million years of the Solar System.
The latest theory on planet formation hypothesises that small planetary bodies collide with each other to create larger worlds.
To form a terrestrial planet the size of Earth, tens of proto-planets between the sizes of the Moon and Mars would need to smash and stick together over time, yet we haven’t been able to see the remains of these ancient astronomical objects since.
Almahatta Sitta meteorite fragment. Credit: NASA/Paul Jenniskens.
“We have long suspected that some of the asteroids are relics from the messy business of planet formation,” says Professor Alan Duffy, Lead Scientist at The Royal Institution of Australia and astrophysicist at Swinburne University.
“It has long been expected that asteroids in our solar system can be chipped away from the collision between these worlds, and that many billions of years later will land on Earth as a fossil record of their formation.”
Lead researcher Farhand Nabiei and colleagues examined tiny crystal strands embedded in the diamonds to predict the conditions within the heated mantle of its ureilite parent body.
Although many of these strands were damaged by gradual accretion and the impact of the meteorite’s fall in the Nubian Desert in 2008, the team used transmission electron microscopy to discover these rocks were formed at sustained, high pressures above 20 gigapascals, a force that is 200,000 times the pressure we experience on the Earth’s surface.
“The diamonds act as the hardest time capsule imaginable and preserve the chemical mix in the mantle of this ancient baby world, revealing the minimum pressures it must have experienced to form,” says Duffy.
“That enormous pressure means the world was at least Mercury-sized, if not as big as Mars.”
This research not only improves our current knowledge on planetary formation, but allows scientists to better examine collected meteorite samples for any related material to the existence of more proto-planets.
The study was published in Nature Communications.
