The biggest planet in the solar system might be a bully, not a protector, as previously believed.
Jupiter has been catching passing rocks and flinging them at Earth, rather than sucking them away, two astronomers have claimed.
Physicist Kevin Grazier and astrobiologist Jonti Horner told tech news site Gizmodo their research has "laid to rest" beliefs that Jupiter protects the inner planets.
"Our simulations show that Jupiter is just as likely to send comets at Earth as deflect them away, and we’ve seen that in the real solar system," said Grazier, who has worked for NASA and consulted on science fiction productions like Battlestar Galactica and Gravity.
"It takes things that threaten Earth and flings them away, clearing space near our planet. So in that sense, it is something of a shield," said Horner, of the University of Southern Queensland.
"On the flip side, though, it takes things that come nowhere near Earth and flings them our way, meaning it is also a threat."
Icy bodies in the outer solar system known as Centaurs can be pulled in by Jupiter's immense gravity, the scientists say, turning them into potentially deadly comets.
This was great in Earth's early years - it's believed early comets asteroids brought to Earth stuff essential for life - but now that we've made a home here, it's not so great.
"We already know that Earth is in the cosmic cross-hairs," said Grazier. "There are hundreds of near-Earth objects that are potentially hazardous. I think we now just have to pay more attention to what's happening a bit farther away in Jupiter's neighbourhood."
Horner and Grazier have published two recent papers on the threat Jupiter poses, one in the Monthly Notices of the Royal Astronomical Society and the other in the Astronomical Journal.
