The Cerberus of the asteroid world has been discovered – and let’s hope it won’t crash into Earth anytime soon.
A lone stargazer discovered 44 Nysa from his flat in 1857, seeing just a pinprick of light in the sky between Mars and Jupiter.
But a joint effort by scientists in Arizona and Chile has discovered that Nysa isn’t your average rock – it has not one, not two, but three heads.
The 47-mile-wide space rock marks the first time a three-lobed asteroid has been discovered. And it even has its own moon.
‘A colleague of mine recently told me she was “disturbed” to know that this thing was out there and we didn’t know about it,’ Kate Minker, the study’s lead author at the Lowell Observatory in Flagstaff, Arizona, tells .
‘I think it’s a really great example of how much we don’t know what we don’t know. It’s definitely possible there are more out there.’
Nysa is named after the nymph in Greek mythology who cared for the goddess of marriage and family, Hera, and the wine-making god Dionysus.
German-French star-gazer Hermann Goldschmidt spotted the rock using a 10cm telescope he stored on the top floor of his flat.
Nearly 170 years later, Minker and her team used slightly more advanced equipment to get a close-up of Nysa.
As Minker’s team wrote in the paper published on the website arXiv, they used the rather literally named Large Binocular Telescope in Arizona and the Very Large Telescope on Paranal mountain in Chile.
There, they found the rock has two valleys wrapping around its circumference, which are the necks of lobes.
They even spotted a 0.6-mile-wide moon doing laps around Nysa 106 miles away, which they called S/2026 (44) 1.
While we’ve had our fair share of ‘city-killer’ asteroid scares in recent years, Minker says we have nothing to worry about.
‘Nysa will not be hitting Earth anytime soon – and that’s a good thing, because if it did we’d be toast,’ she says. (At the time of writing, it’s about 27,300,000 miles away from Earth.)
‘For context, the Chicxulub impactor, famous for sparking the mass extinction of the dinosaurs, was about 10km in diameter – meaning that Nysa is about seven times as wide, and therefore about 400 times the volume of that object and likely a higher density.
This would cause a significantly more energetic impact… the aftermath would definitely be on a global scale.’
Minker adds that some loose chunks of Nysa, such as this ‘itty bitty 2m one’, could be hazardous to Earth as they are near-Earth objects (NEA).
Experts have previously told that we do have a few ways we could defend ourselves against an NEA colliding with the Earth.
They range from smashing an asteroid with a probe to nudge it off-course, or drilling a hole into it and exploding a nuclear weapon.
But why is it shaped like that?
Minker isn’t sure why Nysa is shaped like a three-chambered peanut but believes the lobes could be smushed moons or ‘some exotic’ fracture.
It could be a ‘contact trinary’, three smaller space rocks glued together by gravity, or just an asteroid that’s been battered around by larger ones.
A chunk of the debris could have hitchhiked onto Nysa and formed a moon, Minker says, though there should be more floating around if so.
Two-lobed asteroids, otherwise called ‘cosmic snowmen’, are thought to form when space rocks contract under their own gravity.
For now, astronomers know Nysa is made of the streaky mineral called enstatite, which lacks the iron typical of most space rocks.
This makes it an ‘E-type’ asteroid, made from primordial dirt near the Sun that was forged at the dawn of the solar system.
Most of the time, scientists look to the ring of ancient, icy debris beyond Neptune called the Kuiper Belt for answers.
‘However, we don’t live in the Kuiper Belt; we live in the inner Solar System where terrestrial planets formed,’ she says of Mercury, Venus, Mars and, of course, Earth.
‘There is a lot less direct evidence for how this happened, since most of that material ended up in the planets so it’s not floating around for us to look at.’
Whatever space dirt that failed to form planets was left formed the asteroid belt between Mars and Jupiter, where Nysa is.
Minker says that studying Nysa would give us clues about how the Earth formed some 4.5billion years ago, as we haven’t had a chance to study asteroids quite like it before.
‘Some facet of the material properties may make it more likely to form like this,’ Minker says, ‘making these objects really interesting test subjects to try to understand that process better.’
Get in touch with our news team by emailing us at webnews@metro.co.uk.
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