Is Jupiter Earth's Cosmic Protector? 222
Hugh Pickens writes "Last Sunday, an object, probably a comet that nobody saw coming, plowed into Jupiter's colorful cloud tops, splashing up debris and leaving a black eye the size of the Pacific Ocean — the second time in 15 years that this had happened, after Comet Shoemaker-Levy 9 fell apart and its pieces crashed into Jupiter in 1994, leaving Earth-size marks that persisted up to a year. 'Better Jupiter than Earth,' say astronomers who think that part of what makes Earth such a nice place to live is that Jupiter acts as a gravitational shield, deflecting incoming space junk away from the inner solar system where it could do to humans what an asteroid apparently did for the dinosaurs 65 million years ago. 'If anything like that had hit the Earth it would have been curtains for us, so we can feel very happy that Jupiter is doing its vacuum-cleaner job and hoovering up all these large pieces before they come for us,' says Australian amateur astronomer Anthony Wesley, who first noticed the mark on Jupiter. But others say the warm and fuzzy image of the King of Planets as father-protector may not be entirely accurate. In 1770, Comet Lexell whizzed by the earth, missing us by a cosmic whisker after passing close to Jupiter. The comet made two passes around the Sun and in 1779 again passed very close to Jupiter, which then threw it back out of the solar system."
Re:Is Jupiter Earth's Cosmic Protector? (Score:5, Informative)
the far side is much more cratered than the front side which shows how the Earth
...which is much larger than the moon, protects the moon from impacts more than the other way around.
Re:Orbital Mechanics, not Conscious Intention (Score:2, Informative)
The author of TFS obviously didn't claim that Jupiter takes them all since he mentioned the dinosaur extinction. Since your post is devoted to attacking something that wasn't said, we can safely ignore it. Thanks.
Re:A New Criteria? (Score:3, Informative)
Re:On a galactic note... (Score:3, Informative)
It's a bit like saying one speck of dust is protecting another speck of dust from other, smaller dust, as they swirl around an eddy of warm air in a coliseum.
Right, if the dust is going fast enough to vaporize on impact... Hey, that might be pretty except for the UV damage to the eyes. Anyway, as someone stuck on the "protected" speck, I'll take any extra protection I can get... Sure hope our magnetic field "condom" continues to hold up against all the nasty stuff in the sunlight too...
Re:Is Jupiter Earth's Cosmic Protector? (Score:3, Informative)
Wrong. Both sides of the moon have had the same level of impact
Wrong, the far side has about 1.67 times more recent impacts than the near side (citation [citeulike.org]).
The 'near' side of the moon only looks smoother because mare lava flows have smoothed it out somewhat. It's just chance that put those flows on the side we see.
No, we don't know that, there surely is a reason other than chance, we just don't know for sure what it is yet. Also, not all of it was covered by lava flows, and you can tell these areas look different from the far side. Well at least they look different to me.
Fun fact: if the earth had no weather, it would look just like the moon in terms of impact craters.
I'll assume that you chose the word weather instead of atmosphere for a reason, not too sure why, but the Earth is geologically active and has an atmosphere (assuming you weren't talking about there not being an atmosphere) then it would look more like Venus. And Venus doesn't have so many visible craters. Yeah, there's quite a difference between a body that died over 3 billion years ago and one that's still active, radiating and erupting.
Re:Luckily... (Score:2, Informative)
This part of the neighborhood is getting boring.
Re:Uhhhhhh.....NO (Score:3, Informative)
Re:On a galactic note... (Score:3, Informative)
It's a bit like saying one speck of dust is protecting another speck of dust from other, smaller dust, as they swirl around an eddy of warm air in a coliseum.
The difference is that the bulk of material in the solar system lies in a plane, and while Jupiter may only cover a tiny fraction of that plane _on any given orbit_ it, and its gravity, does cover a larger radial sweep than the Earth does, so when an object makes enough passes to have a significant chance of hitting Earth, the chance of getting ejected or consumed by Jupiter is much greater.
I'd hardly call it a 100% effective shield, but Earth's rate of bombardment may be an order of magnitude or two lower because of Jupiter's presence.
On a funny note, I was just reading the liner notes of this album [wikipedia.org] yesterday, which calls out the very same theory of Jupiter as Earth's protector.
Re:A good reason for manned exploration... (Score:3, Informative)
I think you're missing the benefit of people going into space:
Really smart people the best of humanity no longer have to answer to the politics of the earth and therefore can have new moralities based on secular science that don't have to cow to the stupids, a civilization on another planet is not within reach of the crazy fundies here on earth.
When the earth was less populated it was possible to create new traditions and moralities by moving away and setting up your own shop, now imagine you can do that in a less hostile atmosphere with technology where people are smarter and better then the average human being.