Apropos of absolutely nothing, would it make any difference to us if, tomorrow, all the other planets of the solar system were to completely disappear (I’m aware that the method of disappearance would probably be of greater concern than the disappearance itself, but for the sake of argument let’s just assume they vanish), or if other planets simply did not form, or were somehow flung off into interstellar space early in the history of the Solar System?
I’m aware that the Jovian gravitational pull acts as a sort of ‘vacuum cleaner’, sucking in comets and other cosmic bric-a-brac, so we’d rather be with Jupiter than without it.
I’m guessing we probably wouldn’t miss planet(oids) like Mercury and Pluto all that much. Would our orbit be affected in any way? Given the vast mass of the sun and the comparative minuteness of any effects the gravitational pull (the discredited ‘planetary alignment’ doomsday sayer argument) of the other planets. Would a lack of Luna make any difference, also?
TL;DR - Would it make any difference to us if Earth was suddenly the only body in the Solar System other than Sol?
Long Term - more comets and random rocks would be problematic, as you mentioned.
Every part of the solar system from Venus to Neptune is vital in keeping Earth in the habitable zone for a long enough term to develop life to where it is now. If nothing else each planet sheparded the nearby planets into near circular orbits. I can’t outright write off Mercury, but Pluto and all that other stuff beyond Neptune was important early on, (Comets may have brought Ice/Water to earth) but not so much important for the future.
If it were just Earth and Sol…We’d be a geologically dead, wet rock. Life may have still happened without the moon…but the moon certainly helps.
The other bodies did play a role in circularizing the Earth’s orbit, but a two-body orbit (like the Earth around the Sun) is stable. Once you’ve got a planet in a circular orbit, absent any other bodies, it’s going to stay in a circular orbit forever.
And the loss of Jupiter keeping our space clean would hardly be a problem, if all of the comets and asteroids it sweeps up were also gone. Even at that, the Solar System is pretty empty nowadays, so even if you left all the comets and asteroids in place, they still wouldn’t be much of a threat.
Not so inconsequential actually. A decent chunk of early science and mathematics was developed to predict planetary motions for horoscopes and calendars, I could see the lack of that impetus delaying human progress a couple centuries. Granted there’d still be the sun and moon and the fixed stars.
According to the assumption, nothing but Earth is left in te Solar System, as of now. The effect of the Moon’s absence would alter tides significantly – which might in turn change deposition patterns and what is accessible (there are some ports only accessible to oceangoing ships at high tide, if I’m not mistaken).
However, in planetary formation, I’m given to understand that Jupiter had a relatively important ‘shepherding’ role in causing the assortment of smaller bodies to coalesce into the worlds we know, as well as in “sweeping clear” debris left over so we don’t have dinosaur killer impacts every few years. So there may be an issue in whether Earth would have formed as the size planet we know and love in the absence of Jupiter.
IIRC the moon is still to this day important in stabilizing the earths axis of rotation. IIRC if you got rid of it the Earth would be subject to some serious “axial flips” in fairly short order ( a few million to 10s of millions of years). Wouldnt wipe out life on Earth, but it would make global warming and ice ages look piddly by comparision.
Jupiter is still somewhat important in getting rid of comets. Though my WAG is that Jupiter being gone would eventually be a problem in the 100s of millions of years range statistically speaking.
sigh No, it wouldn’t. This pernicious nonsense stems from the French astronomer Jacques Laskar, whose work his highly criticized, uses a number of methods that make his conclusions suspect, and in general is not well-regarded. Other studies, such as Project LONGSTOP have concluded that while there are chaotic responses to perturbative influences between planets, these tend to damp out for a body the size of the Earth. Earth’s rotational axis may shift due to changes in the mass distribution of the mantle and would probably undergo greater fluctuations in nutation, but these would be gradual changes, not “axial flips” or polar shifts described by doomseers.
billfish678, regardless of whether Laskar’s work is valid or not, the other planets are providing the perturbations causing the (alleged) axis wandering, so the Earth’s axis would be stable if the Moon and all the other planets were gone.
I just recall a study claiming that the moon stabilized the earths axis…and it wasnt something I read in the National Enquirer…
If its somewhat bogus science published in a somewhat not perfect journal sue me… and if doesnt perfectly apply to a hypothectical that will never happen, couldnt even happen, and probably has a dozen unforeseen consequences…well…
Without the other planets we probably wouldn’t have any short period comets. Short period comets ultimately come from the Kuiper Belt. Objects from there are perturbed into noncircular orbits by Neptune. These may be further perturbed by the other outer system planets. Think of it as Neptune handing them off to Uranus, which then passes them to Saturn. Eventually Jupiter either swallows them or sends them into the inner system, where they become short period comets and a hazard to dinosaurs and other living things.
So Jupiter does sort of guard us from comets, but it wouldn’t need to do that if it didn’t exist!
It doesn’t really have much effect on long period comets, which would still be around without the planets.
