Meteorites used to crash into Earth all the time. What makes the meteorite shard called Hypatia unusual is where it possibly came from, and that could mean a seismic shift in the understanding of how our solar system formed and evolved—or what extrasolar star systems are made of.
Unearthed in southwest Egypt in 1996, the Hypatia stone (named after female astronomer and mathematician Hypatia of Alexandria) confounded scientists who examined it further and found bizarre mineral compounds. Wherever they came from, that place definitely wasn’t our planet.
“You don’t want to be like the guy that says, ‘I don’t want to say it’s aliens, but it’s aliens,’” planetary physicist Philip Metzger told Seeker. “Is this rock possibly from outside the solar system? Parts of it almost certainly are but that’s not unusual. A lot of material in the solar system contains pre-solar grains.”
Metzger echoes a study by researchers Jan Kramers and Georgy Belyanin, who confirmed that this piece of rock was not from Earth. Its origins are more complicated. Further investigation by Kramers and Belyanin could either give us insight into the birth of a faraway star system or possibly shatter everything we think we know about how our own came into being.
Think of this strange object as a mass of rock studded with mineral grains that has some Earth dirt lingering in the cracks. No comet or meteorite that ever plummeted through the atmosphere looks remotely like it under a microscope. Chondritic meteorites would have a similar chemical composition to that of Earth if you were to smash the planet into a pile of dust. Think a massive amount of silicon with some carbon.
Kramers observed that Hypatia’s matrix, the mineral mixture in which those grains (more on that later) are embedded in, reverses that with an overwhelming amount of carbon and much less silicon. Things get weird when you realize Hypatia contains the same stuff as interstellar dust. Space dust from outside our solar system is made mostly of polyaromatic hydrocarbons, which the matrix has high levels of. Most of it morphed into micro-diamonds on impact. It was because of these diamonds, which are pretty much impervious to weather, that the specimen stayed intact for 28.5 million years.
The grains in Hypatia are even weirder. When Belyanin anazlyzed them, he found pure metallic aluminum, which rarely occurs on its own outside of a chemical compound. Rare forms of silver iodine phosphide and moissanite were also revealed along with a mostly nickel-phosphorous compound that is not found in meteorites or on Earth.
If the Hypatia stone isn’t a relic from before the sun formed and came from somewhere in our solar system, it could lead scientists to question the idea that our star and planets formed in an enormous cloud of interstellar dust that was supposedly homogeneous, meaning all of it had the same chemical composition. Hypatia literally throws a rock in that theory.
“If Hypatia itself is not presolar, both features indicate that the solar nebula wasn't the same kind of dust everywhere–which starts tugging at the generally accepted view of the formation of our solar system", said Kramers.
The question of Hypatia’s chemical deviance could be answered much more easily if it really is extrasolar. We just need proof that it actually did come from beyond the solar system, or at least proof that nothing in the solar system like it exists.
What Kramers and Belyanin do know is that it formed at temperatures even lower than liquid nitrogen (about -321 Fahrenheit). This opens up the possibility of it being from a rogue comet or asteroid that ran away from the Kuiper Belt or the Oort Cloud. Both of these flying object zones are within the solar system, except we know hardly anything about the chemistry of things that far out.
Until can actually extract samples from objects that distant, the mystery of Hypatia will remain exactly that.