Late last year, scientists discovered the asteroid ‘Oumuamua which travelled through our solar system after arriving from another star.
While the cigar-shaped asteroid passed through the solar system, scientists began theorising that asteroids could have come from far away and then stayed.
This has now been confirmed after scientists found a space rock called 2015 BZ509.
The asteroid was actually first discovered in 2014, but after four years of tracking it, scientists have been able to determine that the rock arrived in our solar system some 4.5 billion years ago – just as Earth was beginning to form.
The asteroid orbits the sun clockwise – the opposite way to all the planets – and is in the same path as Jupiter.
Astronomer and cosmologist Fathi Namouni of the Observatoire de la Côte d’Azur in France said: “How the asteroid came to move in this way while sharing Jupiter’s orbit has until now been a mystery.
“If 2015 BZ509 were a native of our system, it should have had the same original direction as all of the other planets and asteroids, inherited from the cloud of gas and dust that formed them.”
After running computer simulations on the asteroid, they found that it has been there for 4.5 billion years and it will continue on that path for 43 billion more years – although this will not happen as our sun would have burned out by that point.
Study co-author Helena Morais of the Universidade Estadual Paulista, Brazil, said: “Asteroid immigration from other star systems occurs because the Sun initially formed in a tightly-packed star cluster, where every star had its own system of planets and asteroids.
“The close proximity of the stars, aided by the gravitational forces of the planets, help these systems attract, remove and capture asteroids from one another.”