Our Solar System stole asteroids from interstellar space
A cache of interstellar asteroids may have been hiding under scientists’ noses for billions of years according to new research focused on a handful of strange space rocks known as Centaurs, which orbit the Sun in the neighbourhood of Jupiter and Saturn.
Centaurs’ orbits are very unpredictable, with simulations suggesting that they should bang into things or fly out of the Solar System. The new research suggests that’s because they were stolen by our Solar System when it was very young. With so much less expansion under the universe’s belt, stars were closer. “The close proximity of the stars meant that they felt each others’ gravity much more strongly in those early days than they do today,” said Fathi Namouni, an astronomer at Observatoire de la Côte d’Azur in France. “This enabled asteroids to be pulled from one star system to another.”
The new research focused on 21 objects in the outer Solar System: mostly Centaurs and a few other strange space rocks. Using a computer program, the scientists virtually cloned these objects tens of thousands of times over to understand likely scenarios for their escapades.
The analysis suggests that the Centaurs’ strangebut-steady orbits are a hint they were born beyond our Solar System and trapped here. Scientists have long hypothesised that objects move between solar systems, seeing the first confirmed interlopers in our neighbourhood in the past few years with ‘Oumuamua and Comet Borisov.
Both of those objects only passed through our Solar System and weren’t caught by the Sun’s gravity. Scientists think early asteroids may have been more likely to wander into other star systems and get stuck because in the early days of the
Solar System, with more than 4 billion years less of expansion, things were closer together.