Seven years ago, astronomers were surprised to find the first runaway star moving out of our galaxy at a speed of 2.4 million kilometers per hour. The question they asked themselves was: if a star can reach such extreme speed, could the same thing happen with the planets?
New research shows that it is. What’s more, they not only existplanets “out of control”, but some of themmove through space at 30 million miles per hour. “These planets would be some of the fastest objects in our galaxy. If someone lived in one of them, they would be on a wild ride from the center of the galaxy to the Universe,” said astrophysicist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. “Apart from subatomic particles, we know of nothing that leaves our galaxy as fast as these planets“added lead author Idan Ginsburg of Dartmouth University.
These new worlds, calledplanets at hypervelocity, they occur when a star system with planets in close orbit wanders too close to the supermassive black hole that occupies the center of the galaxy, and strong gravitational forces push one of them at full speed outwards, while the other is captured orbiting the black hole. The expelled outward star could take its planets on the journey. The second star, captured by the black hole, could be stripped of its planets and they would be thrown into the icy darkness of interstellar space at enormous speeds.
A typical hypervelocity planet catapults at a speed of 7 to 10 million kilometers per hour. However, a small fraction of them could achieve much higher speeds under ideal conditions.
The research will be published in the journalMonthly Notices of the Royal Astronomical Society.
