Jupiter Increases Risk Of Comet Strike On Earth

New Scientist ^ | 8-24-2007 | David Shiga

[blam]

Jupiter increases risk of comet strike on Earth

11:53 24 August 2007
NewScientist.com news service
David Shiga

Earth experienced an especially heavy bombardment of asteroids and comets early in the solar system's history (Illustration: Julian Baum)

Contrary to prevailing wisdom, Jupiter does not protect Earth from comet strikes. In fact, Earth would suffer fewer impacts without the influence of Jupiter's gravity, a new study says. It could have implications for determining which solar systems are most hospitable to life.

A 1994 study showed that replacing Jupiter with a much smaller planet like Uranus or Neptune would lead to 1000 times as many long-period comets hitting Earth. This led to speculation that complex life would have a hard time developing in solar systems without a Jupiter-like planet because of more intense bombardment by comets.

But a new study by Jonathan Horner and Barrie Jones of Open University in Milton Keynes, UK, shows that if there were no planet at all in Jupiter's orbit, Earth would actually be safer from impacts.

The contradictory results arise because Jupiter affects comets in two different, competing ways. Its gravity helps pull comets into the inner solar system, where they have a chance of hitting Earth, but can also clear away Earth-threatening comets by ejecting them from the solar system altogether, via a gravitational slingshot effect.

Tripled impacts

According to the new study, the worst scenario for Earth is when Jupiter is replaced by a planet with about the mass of Saturn. "[Such a planet] is fairly capable of putting things into an Earth-crossing orbit, but still has some difficulty ejecting them, so they will stay on an Earth-crossing orbit for a much longer time," Horner told New Scientist. The projected result was more than three times as

[El Gato]

Darn, you mean somebody stole my idea before I even had it. Drat, I hate it when that happens. But it happens a lot.

OTOH, great minds tend to work alike.

[mikrofon]

"D*mn, with this new iRove I can't tell if I'm
diverting the asteroids toward or away from Earth..."

[Hot Tabasco]

Then we’re all in agreement.....Jupiter must be destroyed!

Well, since the lefties have already stripped Pluto of its planet status, don't expect any help from them........They're pissed!

[SunkenCiv]

:’)

[Army Air Corps]

I still believe that the earth is a very privileged planet, in many ways.

Jolly right! We are the only planet with queso dip and nuoc mam.