Only Jupiter protects us?

[Airbrush]

I've heard this several times before, but what about Saturn, Uranus, Neptune and the Asteroid Belt? It seems to me that we get protection from ALL those. Any comet coming from outside our solar system, that is moving on the plane of our solar system, must pass all those obstacles before hitting Earth. Especially the asteroid belt, since there are so many objects there that can hinder a comet with our name on it. I left out Mars, since it is so small compared to the others I mentioned above. But even Mars and the Moon could possibly take a hit for us.

Edited August 6, 2013 by Airbrush

[mathematic]

You need to describe in detail what you mean by "Jupiter protects us".

[Spyman]

Jupiter has been called the Solar System's vacuum cleaner, because of its immense gravity well and location near the inner Solar System. It receives the most frequent comet impacts of the Solar System's planets. It was thought that the planet served to partially shield the inner system from cometary bombardment. Recent computer simulations suggest that Jupiter does not cause a net decrease in the number of comets that pass through the inner Solar System, as its gravity perturbs their orbits inward in roughly the same numbers that it accretes or ejects them. This topic remains controversial among astronomers, as some believe it draws comets towards Earth from the Kuiper belt while others believe that Jupiter protects Earth from the alleged Oort cloud.
http://en.wikipedia.org/wiki/Jupiter#Impacts

[Airbrush]

Thanks Spyman, that's the answer, mostly because Jupiter is closest to the INNER solar system and it's greater mass results in it having a much more active role in perturbing asteroids in our vicinity. But some argue that it also acts like a magnet pulling asteroids or comets in towards us.

 

Why would the asteroid belt not help block such possible impactors? That is even closer to us than Jupiter.

Edited August 8, 2013 by Airbrush

[Delta1212]

Thanks Spyman, that's the answer, mostly because Jupiter is closest to the INNER solar system and it's greater mass results in it having a much more active role in perturbing asteroids in our vicinity. But some argue that it also acts like a magnet pulling asteroids or comets in towards us.

 

Why would the asteroid belt not help block such possible impactors? That is even closer to us than Jupiter.

The asteroid belt is not very massive. People picture it as this dense ring of asteroids, but two asteroids being within 100 miles of each other in the belt would be close together. It's very spread out, so the odds of a comet colliding with anything by chance is pretty small, and the odds of colliding with anything large enough to slow it down are even smaller.

 

Jupiter at least has its gravity, but the mass in the asteroid belt is so dispersed that it doesn't generate enough to deflect anything.