Jupiter: Taking One for the Gipper

Last week, a comet smashed into Jupiter. The damage: a hole the size of the Pacific Ocean. If not for Jupiter, some say, that hole would have decimated Earth. But Jupiter, huge and gravitationally attractive, stood bravely between us and destruction.

As it turns out Jupiter has stood between us and destruction more than once.

For example, according to an article in the New York Times, Jupiter has shielded us for millennia from asteroids in the "... Oort Cloud, a vast spherical deep-freeze surrounding the solar system as far as a light-year from the Sun. Every once in a while, in response to gravitational nudges from a passing star or gas cloud, a comet is unleashed from storage and comes crashing inward." When that happens, Jupiter and its gas-giant sister Saturn attract the lion's share of dangerous flying space debris.

Despite its protective role, though, Jupiter isn't all sweetness and light. In fact, some astronomers say, the biggest planet in our solar system occasionally turns ugly. Like that time back in the 1700s when a comet was caught in Jupiter's orbit and slingshot toward Earth. One astronomer puts it like this: “It was as if Jupiter aimed at us and missed! ... The comet would never have come anywhere near the Earth if Jupiter hadn’t thrown it at us in the first place."

On average, it seems that Jupiter's done a pretty good job of taking meteoric whacks for the Gipper. But don't get too comfortable. It seems that our planetary protector tends to swing both ways.

Image courtesy of NASA, ESA, and H. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team.