A pebble found in a field of Libyan desert glass in southwest Egypt has proven to be quite a mystery, and may even shake up our very understanding of the history of our solar system. The pebble is known as the Hypatia Stone, named after 4th century Greek philosopher and mathematician Hypatia who is remembered as being one of the first notable female mathematicians. The pebble appears unremarkable on the surface, measuring just a few centimeters across and dark grey in color. What makes the pebble unique is its chemical composition, one that is unlike any other known substance on Earth or in space. Where did the Hypatia stone come from?
Most planets and known meteorites contain silicate minerals and a small amount of carbon, but the Hypatia pebble has been found to have a nearly opposite composition of mostly carbon with very little silicon. Even stranger, the pebble contains a high amount of polyaromatic hydrocarbons, a major component of interstellar dust which existed before our own solar system formed. Georgy Belyanin, a geologist at the University of Johannesburg and one of the authors of the study of the hypatia stone, says this unique composition may date it to before the birth of our own Sun and place its origin outside of our own solar system:
In the grains within Hypatia the ratios of these three elements to each other are completely different from that calculated for the planet Earth or measured in known types of meteorites. As such these inclusions are unique within our solar system. We think the nickel-phosphorus-iron grains formed pre-solar, because they are inside the matrix, and are unlikely to have been modified by shock such as collision with the Earth’s atmosphere or surface, and also because their composition is so alien to our solar system.
If confirmed, that would make it the only own fragment from this period of the universe’s history. It’s still unknown from where the pebble originated, however. There is a chance it could have originated in a comet or meteorite from the far edges of our solar system, but since we haven’t been able study those objects, scientists are still unsure of their compositions. Furthermore, if it came from our solar system, it would challenge our entire understanding of how our solar system formed. Pretty impressive for a pebble.