In 2013, the UJ researchers announced that the Hypatia pebble found in southwest Egypt was "definitely not from Earth".
Researchers from the department of geology at the University of Johannesburg found exotic micro-mineral compounds in the "Hypatia" stone that are not known to occur on Earth, elsewhere in our solar system or in known meteorites or comets.
The researchers said the discovery of Hypatia presented a "tantalising piece for an extraterrestrial puzzle that is getting ever more complex".
"If it were possible to grind up the entire planet Earth to dust in a huge mortar and pestle, we would get dust with on average a similar chemical composition as chondritic meteorites", Prof Jan Kramers, lead researcher of the new study, said in a statement. Micro-mineral analyses of the pebble by Kramers and his colleague, Dr Georgy Belyanin, have now provided unsettling answers that spiral away from conventional views of the material our solar system was formed from. "Interstellar dust is also found in comets and meteorites that have not been heated up for a prolonged period in their history". It shows the enormous differences for all elements and how radically different Hypatia's chemical blend is from known objects in our solar system.
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"We also found silver iodine phosphide and moissanite (silicon carbide) grains, again in highly unexpected forms". One of the most unusual compounds, a mixture of phosphorus and nickel, with no iron was also found within the alien stone. "That means, matter that existed in space before our Sun, the Earth and the other planets in our solar system were formed", he said.
"What we do know is that Hypatia was formed in a cold environment, probably at temperatures below that of liquid nitrogen on Earth (-196 Celsius)", said the university's Professor Jan Kramers, a geochemist now specialising in dating techniques (especially for hominin fossils) and analysis of extraterrestrial objects.
'Some come from the Oort Cloud, even further out. In our Solar System it would have been way further out than the asteroid belt between Mars and Jupiter, where most meteorites come from. We know very little about the chemical compositions of space objects out there.