Astronomers believed that Jupiter was protecting Earth from dangerous comets and asteroids.
A new research shows the opposite: The gas giant is actually actively flinging objects into the inner solar system.
There is a popular theory suggesting that Jupiter, with its tremendous mass, acts like a gigantic shield in space, sucking in or deflecting dangerous space objects left over from the formation of the solar system. But a group of astronomers suggests the opposite: Jupiter is more a sniper than a shield.
In a pair of papers, Grazier shows how Jovian planets – Jupiter, Saturn, Neptune, and Uranus – affect other objects in the outer solar system and how icy bodies can be transformed by Jupiter into potentially deadly comets.
The latest 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.
Such an impact would trigger mass extinctions similar to the one that extinguished non-avian dinosaurs some 66 million years ago.
Turning distant celestial bodies into local threats
Grazier’s works demonstrate the complex astrophysical processes required to convert distant celestial bodies into local threats. The publications indeed show how Centaurs, a group of icy bodies in orbit beyond Jupiter and Neptune, are transformed by Jupiter into potentially Earth-threatening comets.
It also testifies that Centaur objects, Jupiter Family Comets, and objects in the Scattered Disk are not dynamically distinct populations, but evolve under the gravitational influence of the Jovian planets.
Finally, the new model affirms that Centaurs are fed by the scattered disc and that the Jovian planets play a role in this process and shows how Jupiter Family Comets (JFCs) are born.
Birth of dangerous Jupiter family comets
In their simulations, a large fraction of the objects that become JFCs are first grabbed by Jupiter into what are called temporary capture orbits, or TSCs. These orbits circle Jupiter a few times, then leave Jupiter, often on a very different orbit.
A good example for TSC is comet P/111 Helin-Roman-Crockett that spent over 11 years in orbit around Jupiter in the 70s and 80s, and will be captured again in the 2070s.
And we have known that Jupiter converts outer Solar system objects into JFCs. In 1767, an object called D/1770 L1 Lexell made a close approach to Jupiter, causing it to migrate into an Earth-crossing orbit, thus becoming the first-known Jupiter Family Comet.
Another interesting aspect of those simulations is that Saturn, Uranus and Neptune also have their own comet families.
Does Jupiter protects Earth from celestial objects?
Yes. Gas giants protect Earth from objects caught between them but not from those found in the outer solar system.
Jupiter takes things that threaten Earth and flings them away, clearing space near our planet. So in that sense, it is something of a shield.
On the flip side, though, Jupiter takes things that come nowhere near Earth and flings them our way, meaning it is also a threat.
We already know that Earth is in the cosmic cross-hairs. 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. Meanwhile Jupiter’s storm is decreasing. Find similar headlines on Strange Sounds and Steve Quayle. [Gizmodo]