Scientists discover that the Hypatia stone, a collection of mysterious rock fragments, dates back to before the solar system was born.
What can the fragments of the Hypatia stone tell us about the days before our solar system was born? [Photo by Dr Mario di Martino, INAF Osservatorio Astrofysico di Torino]
Hypatia was discovered in December 1996 in a part of an Egyptian desert littered with yellow glass. It was a strange stone taken from a strange region of the desert and named “Hypatia” after Hypatia of Alexandria, a female ancient Egyptian astronomer and mathematician. Later on, it was discovered that the stone had extraterrestrial origins and was touted as the first known fragment of a comet nucleus ever found.
However, it turned out that there’s more to the Hypatia stone that scientists haven’t discovered yet. It was certainly a mystery, since it was very hard but at the same time brittle and already fragmented. 17 years after the stone was first discovered, scientists confirmed that it was indeed from outer space, but it didn’t fall under any known comet or meteorite categories.
The stone was found in the same area as the mysterious Libyan desert glass. [Photo by Mohamed El-Hebeishy]
The findings of a new study are challenging what scientists thought they knew about the materials that formed the solar system, and our solar system itself. Looking into the insides of the stone clears up a lot of the confusion, but brings up a lot of new questions as well.
The study’s lead author Prof. Jan Kramers likens the internal structure of the Hypatia stone to a fruitcake. "We can think of the badly mixed dough of a fruit cake representing the bulk of the Hypatia pebble, what we called two mixed 'matrices' in geology terms,” says Kramers. “The glace cherries and nuts in the cake represent the mineral grains found in Hypatia 'inclusions'. And the flour dusting the cracks of the fallen cake represent the 'secondary materials' we found in the fractures in Hypatia, which are from Earth."
What was immediately clear is that the mix of Hypatia’s minerals does not resemble that of any known meteorites. These meteorites usually have a bit of carbon and a lot of silicone, but Hypatia has large amounts of carbon and tiny amounts of silicone. The carbon content also had a high amount of polyaromatic hydrocarbons, or PAH. PAH is a component of interstellar dust, which existed before the birth of our solar system.
Video uploaded by James Kelly; credit to Therese van Wyk, University of Johannesburg
But that’s not all. The PAH in Hypatia’s internal structure has also turned into tiny diamonds smaller in diameter than one micrometer. The researchers think that these diamonds may have formed when the extraterrestrial rock that the stone was part of made impact with the Earth’s atmosphere or surface. There are also metals dotting the structure like cherries and nuts in fruitcake, one of the metals being pure aluminum. This is also another surprise find, since aluminum doesn’t naturally occur in nuggets—at least not on Earth, or anywhere else in the solar system as far as we know.
Scientists now think that the bits of metal in Hypatia were once part of the building blocks that formed the solar system. Eventually, these metal chunks were enveloped in interstellar dust that contains PAH and other forms of carbon, which then turned into tiny diamonds upon impact with Earth. It’s possible that the original rock that slammed into our planet was several meters wide, though a few bits of rock are all that remains of it now. Still, these fragments have served as a small window into the era before our solar system was ever formed.
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