{"id":46418,"date":"2020-09-29T14:28:25","date_gmt":"2020-09-29T12:28:25","guid":{"rendered":"https:\/\/aktuelles.uni-frankfurt.de\/?p=46418"},"modified":"2023-02-22T14:17:17","modified_gmt":"2023-02-22T13:17:17","slug":"geoscience-cosmic-diamonds-formed-during-gigantic-planetary-collisions","status":"publish","type":"post","link":"https:\/\/aktuelles.uni-frankfurt.de\/en\/english\/geoscience-cosmic-diamonds-formed-during-gigantic-planetary-collisions\/","title":{"rendered":"Geoscience: Cosmic diamonds formed during gigantic planetary collisions"},"content":{"rendered":"
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Artist\u2019s impression of the collision of two protoplanets.Credits: NASA\/SOFIA\/Lynette Cook https:\/\/www.nasa.gov\/image-feature\/what-happens-when-planets-collide<\/a><\/em><\/figcaption><\/figure><\/div>\n\n\n\n

Geoscientists from Goethe University have found the largest extraterrestrial diamonds ever discovered \u2013 a few tenths of a millimetre in size nevertheless \u2013 inside meteorites. Together with an international team of researchers, they have now been able to prove that these diamonds formed in the early period of our solar system when minor planets collided together or with large asteroids. These new data disprove the theory that they originated deep inside planets \u2013 similar to diamonds formed on Earth – at least the size of Mercury. <\/strong><\/p>\n\n\n\n

It is estimated that over 10 million\nasteroids are circling the Earth in the asteroid belt. They are relics from the\nearly days of our solar system, when our planets formed out of a large cloud of\ngas and dust rotating around the sun. When asteroids are cast out of orbit,\nthey sometimes plummet towards Earth as meteoroids. If they are big enough,\nthey do not burn up completely when entering the atmosphere and can be found as\nmeteorites. The geoscientific study of such meteorites makes it possible to\ndraw conclusions not only about the evolution and development of planets in the\nsolar system but also their extinction.<\/p>\n\n\n\n

A special type of meteorites are\nureilites. These are fragments of a larger celestial body \u2013 probably a minor\nplanet \u2013 which was smashed to pieces through violent collisions with other\nminor planets or large asteroids. Ureilites often contain large quantities of\ncarbon, among others in the form of graphite or nanodiamonds. The diamonds on\nthe scale of over 0.1 and more millimetres now discovered cannot have formed\nwhen the meteoroids hit the Earth. Impact events with such vast energies would\nmake the meteoroids evaporate completely. That is why it was so far assumed\nthat these larger diamonds \u2013 similar to those in the Earth\u2019s interior \u2013 must\nhave been formed by continuous pressure in the interior of planetary precursors\nthe size of Mars or Mercury.  <\/p>\n\n\n\n

Together with scientists from Italy, the\nUSA, Russia, Saudi Arabia, Switzerland and the Sudan, researchers from Goethe\nUniversity have now found the largest diamonds ever discovered in ureilites\nfrom Morocco and the Sudan and analysed them in detail. Apart from the diamonds\nof up to several 100 micrometres in size, numerous nests of diamonds on just\nnanometre scale as well as nanographite were found in the ureilites. Closer\nanalyses showed that what are known as londsdalite layers exist in the\nnanodiamonds, a modification of diamonds that only occurs through sudden, very\nhigh pressure. Moreover, other minerals (silicates) in the ureilite rocks under\nexamination displayed typical signs of shock pressure. In the end, it was the\npresence of these larger diamonds together with nanodiamonds and nanographite\nthat led to the breakthrough.<\/p>\n\n\n\n

Professor Frank Brenker from the\nDepartment of Geosciences at Goethe University explains:<\/p>\n\n\n\n

\u201cOur extensive new studies show that these unusual extraterrestrial diamonds formed through the immense shock pressure that occurred when a large asteroid or even minor planet smashed into the surface of the ureilite parent body. It\u2019s by all means possible that it was precisely this enormous impact that ultimately led to the complete destruction of the minor planet. This means \u2013 contrary to prior assumptions \u2013 that 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.\u201d<\/p>\n\n\n\n

The international research team comprises\nscientists from the following institutions: <\/p>\n\n\n\n