Mercury

[Fallingstar1971]

Is Mercury the burnt out core of a dead world?

What kind of impact on the orbits of the inner planets would a Jupiter size object in Mercurys orbit have?

Star

 

[vgeric]

Mercury used to have some sort of atmosphere, but being so close to the sun made the gases burn away/blow away (solar wind) from the planet... so maybe that helps answer part of your question!

Eric

 

[MeteorWayne]

It seems unlikely (though not impossible) that Mercury is such a core. As we have learned from our exoplanet discoveries, such bloated planets seem to survive quite well for a long period. But certainly, we have no firm theory of how Mercury formed, or how it got to where it is. That is one of the main goals of the current MESSENGER mission.

 

[Shpaget]

On the Jupiter sized object (by "size" I'll assume you meant mass) in Mercury's orbit would probably not allow inner planets to form as they did in the first place so your question is not really answerable.

If something Jupiter sized just appeared out of nowhere that close to Venus and Earth, it would probably make our orbits lower than they are now and in time it might even suck us in completely (my guess, not based on any calculation).