jupiter takes another one for the team?

Jupiter may have once again saved us from an asteroid impact. But next time, it might steer one our way...

It's official. Something big smashed into Jupiter and left a black mark as big as the Pacific Ocean. The scar was originally captured by an amateur astronomer living in a suburb of Canberra, Australia and verified by teams of professionals as the aftermath of an impact. What exactly hit Jupiter is still a mystery since the object has long disintegrated in the thick atmosphere. So while the gas giant recovers, I thought it might be a good time to take a look at the complex relationship Earth has with Jupiter.

Our solar system isn't a collection of planets and rocks serenely floating around the Sun. In reality, the planets race around our star while marauding bits of rock are screaming through at dangerously high speeds. This is where Jupiter comes in. It's powerful gravity helps control large objects, like comets which could otherwise slam into the Earth. Without Jupiter, we should be pelted with so many large impacts, complex life would never evolve on our world. All its gains would be destroyed by another giant piece of rock. Jupiter is a benevolent vacuum cleaner which safeguards our little blue marble. Or so the thinking went…

However, some detailed models and calculations show that it's not quite as simple as that. Yes, Jupiter might protect the inner solar system to some extent, but its gravity also sends objects towards us. It all depends where the projectiles come from and when Jupiter catches them. If a comet comes from the Oort Cloud, it could be sent away from the Earth or fall into Jupiter, like Shoemaker-Levy 9 did in 1994. But when the gas giant perturbs rocks floating around the asteroid belt, it either catches them, flings them out of the solar system, or throws a few our way. The objects sent towards us become dangerous NEOs, or Near Earth Objects.

So as it turns out, rather than guarding us from dangerous debris, Jupiter can both deflect doomsday comets and litter our orbit with hazardous debris. I suppose nature just doesn't do benevolence…