asteroid belt an exploded planet?

[Frostbite]

Ok so I was having this debate with some guy about how possible it is that the asteroid belt between Mars and Jupiter might have been a planet at one point. We agreed that the total mass of the asteroid belt is barely enough to equal a planetoid half the size of the Moon, so then we thought, what about rogue comets and meteors and all the craters on the Solar System's planets. At some point there must've been a lot more debris flying around and we were wondering how likely is an exploded planet hypothesis.

Thanks!

 

[drkitten]

Ok so I was having this debate with some guy about how possible it is that the asteroid belt between Mars and Jupiter might have been a planet at one point. We agreed that the total mass of the asteroid belt is barely enough to equal a planetoid half the size of the Moon, so then we thought, what about rogue comets and meteors and all the craters on the Solar System's planets. At some point there must've been a lot more debris flying around and we were wondering how likely is an exploded planet hypothesis.

My understanding is that the composition of asteroids is radically different than the composition that would be expected from an exploded planet. Basically, planets or planet-like objects -- even small ones like the moon -- have a certain degree of gravitation "fractionation," meaning that the heavy elements like iron sink to the center, and the lighter ones like silicon move to the surface. In the case of the Earth, we talk about the "core" and the "mantle" and the "crust," respectively.

Any time you see a silicon-iron mixture (as you do in a fairly large fraction of asteroids), you can be relatively confident that it didn't come from an exploded planet-like object. A typical "stony asteroid" might be about 25% iron and 25% silicon.

 

[FreakBoy]

I heard another theory that the astroid belt is a failed planet with some bad realty contracts.

With the Jupiter not so far off there would be a constant tug-o-war with any planetoid that started to form. All pieces being tugged by the sun, and then any within range during Jupiter's orbit would be tugged the other way.

But I'm the amateur's amateur.

 

[CaveDave]

The way I understand it, there would be too much gravitational stress to form a single planet at that location. Sort of like the gas giant planets' ring systems, the periodic tugs from other satellites don't allow for much consolidation to take place.

Dave

 

[Just thinking]

Actually what happened is that the inhabitants of Atlantis knew their continent was doomed -- and not liking anywhere else on Earth -- left for the planet just beyond Mars. Alas, they had issues too, and fought among themselves to the point of blowing it all up.

(Shows how advanced they were. They could blow up an entire planet.)

 

[drkitten]

Re: Re: asteroid belt an exploded planet?

Actually what happened is that the inhabitants of Atlantis knew their continent was doomed -- and not liking anywhere else on Earth, they left for the planet just beyond Mars. Alas, they had issues too, and fought among themselves to the point of blowing it all up.

(Shows how advanced they were. They could blow up an entire planet.)

Along with all evidence of themselves as well. Not a single broken sonic screwdriver casing or verteron coil to be found.

Truely a very thorough technology of desctruction.