Okay - the thing is that Mercury is a small planet - and there's a resonance between the tiny Mercury and Jupiter. It just so happens that the perihelion of Mercury (when it is closest to the sun) precesses by about 1.5 degrees every thousand years, which is very close to the rate of precession of the perihelion of Jupiter. No reason why that should be, just a coincidence as far as we know.
They are out of sync at present, but when they are in sync, this can cause Jupiter to keep tugging at Mercury at its perihelion. And it's possible that in the future, some hundreds of millions of years from now, that this effect could pull change its eccentricity enough so it interacts with the other inner solar system planets and gets diverted out of its orbit and start doing gravity assist type flybys of the other inner solar system planets.
Then - with Mercury as a "loose cannon" it could do many things - like our spacecraft when they do gravity assist flybys of the planets - it could end up anywhere in the solar system pretty much. It could hit the sun. It could hit Jupiter. It could escape from the solar system altogether. It could hit Earth or Venus or Mars. Since Mars is so small, then with Mercury changed, that could have repercussions on Mars and send it out of its orbit also, indeed Mars also could escape from the solar system.
None of these are particularly likely to happen. There's at least a 98% probability that nothing happens at all, but a 1 or 2% chance that one of these things happens some time in the future. Not immediately - not for the next few hundred million years. But could happen some time in the next one or two billion years.
For a bit more about this see: Solar system could go haywire before the Sun dies - New Scientist
Stability of the Solar System
Yes I think it could easily leave Venus intact, if it misses Venus and hits Earth. As for turning Earth into an asteroid belt - not so sure about that. The usually accepted view now is that the asteroid belt never did form a single very large body though it surely had some larger asteroids and comets that later got broken up into smaller ones.
For Earth - if it was hit by Mercury - well I expect it would be like the formation of the Moon - lots of debris, but eventually it would all gather together again. Still, immediately after the impact - Earth probably pretty much intact but molten crust - and lots of debris, large asteroids, some forming into a new Moon but many just careering around and eventually hit the other planets. But they would probably all be gone after 20 million years or so, that's how long it typically takes to clear out debris from the inner solar system around Earth.
Still for a science fiction story, 20 million years, though brief in geological timescale, is a huge canvas for your story :).
Needless to say - not something we need to be concerned about with our present solar system right now for at least a hundred million years or so - we are not in the middle of any such resonance of Jupiter with Mercury right now.
They are out of sync at present, but when they are in sync, this can cause Jupiter to keep tugging at Mercury at its perihelion. And it's possible that in the future, some hundreds of millions of years from now, that this effect could pull change its eccentricity enough so it interacts with the other inner solar system planets and gets diverted out of its orbit and start doing gravity assist type flybys of the other inner solar system planets.
Then - with Mercury as a "loose cannon" it could do many things - like our spacecraft when they do gravity assist flybys of the planets - it could end up anywhere in the solar system pretty much. It could hit the sun. It could hit Jupiter. It could escape from the solar system altogether. It could hit Earth or Venus or Mars. Since Mars is so small, then with Mercury changed, that could have repercussions on Mars and send it out of its orbit also, indeed Mars also could escape from the solar system.
None of these are particularly likely to happen. There's at least a 98% probability that nothing happens at all, but a 1 or 2% chance that one of these things happens some time in the future. Not immediately - not for the next few hundred million years. But could happen some time in the next one or two billion years.
For a bit more about this see: Solar system could go haywire before the Sun dies - New Scientist
Stability of the Solar System
Yes I think it could easily leave Venus intact, if it misses Venus and hits Earth. As for turning Earth into an asteroid belt - not so sure about that. The usually accepted view now is that the asteroid belt never did form a single very large body though it surely had some larger asteroids and comets that later got broken up into smaller ones.
For Earth - if it was hit by Mercury - well I expect it would be like the formation of the Moon - lots of debris, but eventually it would all gather together again. Still, immediately after the impact - Earth probably pretty much intact but molten crust - and lots of debris, large asteroids, some forming into a new Moon but many just careering around and eventually hit the other planets. But they would probably all be gone after 20 million years or so, that's how long it typically takes to clear out debris from the inner solar system around Earth.
Still for a science fiction story, 20 million years, though brief in geological timescale, is a huge canvas for your story :).
Needless to say - not something we need to be concerned about with our present solar system right now for at least a hundred million years or so - we are not in the middle of any such resonance of Jupiter with Mercury right now.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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