An artist’s impression of a star being thrown out of the Milky Way after a close encounter with the supermassive black hole at the core of the galaxy. Image: James Josephides (Swinburne Astronomy Productions)
Five million years ago, a binary star system wandered too close to the supermassive black hole lurking at the core of the Milky Way. The hole’s ferocious gravity likely captured one of the stars, but the other was flung away with a velocity of more than 6 million kilometres per hour (3.7 million mph).
That’s fast enough to escape the Milky Way, but even so, it will still take the outward-bound star, known as S5-HVS1, some 100 million years to pass through the galaxy’s outskirts and into the great void of intergalactic space.
“We traced this star’s journey back to the centre of our galaxy, which is pretty exciting,” said Gary Da Costa, an astronomer at the Australian National University. “This star is travelling at record-breaking speed, 10 times faster than most stars in the Milky Way, including our Sun.
“In astronomical terms, the star will be leaving our galaxy fairly soon and it will likely travel through the emptiness of intergalactic space for eternity. It’s ...