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Mars, Mercury May Have Formed From Earth and Venus
goran72 sends along a report on a radical new theory of planet formation that suggests that Mars and Mercury were formed from the scraps of Earth and Venus. The theory has testable predictions — for example that the compositions of the rocky inner planets should be more similar than the current theory of planet formation would have them.
Very true but the 4 inner planets have almost circular orbits.
Any planet that get flung around will have a very eliptical orbit.
The Hot Jupiters are a different thing. They are caused by the system having enough material to cause drag and slow them down enough to collapse the orbit.
Very true but the 4 inner planets have almost circular orbits.
Any planet that get flung around will have a very eliptical orbit.
Orbits get circularized by a number of effects over time, both orbital and viscoelastic coupling. Hot-Jupiter orbits somehow get circularized, after all, and they're much harder to circularize than smaller planet orbits.
The Hot Jupiters are a different thing. They are caused by the system having enough material to cause drag and slow them down enough to collapse the orbit.
Any process that can move Jupiter and super-Jupiter size planets will easily reposition smaller planets.
http://www.geoffreylandis.com
Actually, it's the reverse. If you put a planet in the disk, it tries to open a gap. (See the Keeler and Encke gaps in Saturn's A ring for examples.)
So that's not it. (And besides, it sounds like these guys are positing the bands form FIRST.)
Eccentric orbit's are destabalized during the process of circularization which then either ejects them OR crashes the orbit. But it is also true the eccentric orbits tend to be a bit more stable than true circular ones...but only a little.
I never said the sol system had a hot jupiter. But it had been cited in the grandparent therefore I was adressing the issue. Hot Jupiters happen in specific conditions where the gas that formed the original system was thick enough to not get blown away quickly. Therefore the jupiter sized planet, with it greater porportional size and gravitational field effect due to lower density, are disporportinaly slowed through friction. As they slow they eat or eject all inner planets until they get close enough so that the solar wind HAS cleared everything out.
The sol system did not have these conditions therefore no hot Jupiter.
With the higher density but smaller size of rocky planets they are not as likley to experience the slowing effect before they clear the neighboring space therefore any moving will probably be due to colision or near collision with other large bodies and will be entierly random.
The reason Venus, Earth and Mars probably haven't moved is because the planets chemistries match theory fairly closely. Planetary genesis theories suggest that there will be subtly chemical differences at varius altitudes from the star. Mercury has unexpected chemistry which could come from collision (there is evidence for such an event) or being moved