Extraterrestrial diamonds form when planets collide, study of meteorites' insides finds

Scientists from Goethe University have found the largest extraterrestrial diamonds to be ever discovered inside meteorites. The diamonds are a few tenths of a millimetre in size. According to a statement by the Goethe University, the team of international researchers has been able to prove that the diamonds formed in the early period of the solar system when minor planets collided together or with larger asteroids. According to study authors, these new data disprove theory that the diamonds originated deep inside planets.As per the university statement, at least ten million asteroids are circling the Earth in the asteroid belt. One of these are the Ureilites asteroids – fragments of a larger celestial body that was smashed to pieces through violent collisions with other minor planets or larger asteroids. The Ureilites contain large amount of carbon in the form of graphite or nanodiamonds.According to study authors, diamonds on the scale of over 0.1 and more millimetres could not have had formed when the meteoroids hit the Earth, since such impact with such vast energies would make the meteoroids evaporate completely. And so, it was earlier assumed that these larger diamonds must have been formed by continuous pressure in the interior of planetary precursors the size of Mars or Mercury.[caption id="attachment_8866711" align="alignnone" width="1280"]

A urelite meteorite, NWA 4231. Image Credit: Geology In[/caption]Scientists from the university, along with researchers from Italy, the USA, Russia, Saudi Arabia, Switzerland and the Sudan found the largest diamonds ever discovered in Ureilites from Morocco and the Sudan and analysed them in detail.The researchers found diamonds of up to several 100 micrometres in size as well as numerous nests of diamonds on just nanometre scale as well as nanographite in the Ureilites.Analysis showed that londsdalite layers – modification of diamonds that only occurs through sudden, very high pressure -- exist in the nanodiamonds.Professor Frank Brenker from the Department of Geosciences at Goethe University stated that the studies show that the unusual extraterrestrial diamonds formed through immense shock pressure due to the planetary phenomenon of a large asteroid or even minor planet smashing into the surface of the urelite planet body."This means – contrary to prior assumptions – the larger ureilite diamonds are not a sign that protoplanets the size of Mars or Mercury existed in the early period of our solar system, but nonetheless of the immense, destructive forces that prevailed at that time," he added.