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Absence of Jupiter

  1. Sep 13, 2007 #1
    Absence of Jupiter....

    Jupiter instantaneously vanishes. What are some events likely to happen? Accretion of the asteroid belt? How immediately detrimental to earth would this be?
  2. jcsd
  3. Sep 13, 2007 #2
    Without putting too much thought into it, I imagine that the inner planets would enter a tighter orbit around the sun while the outer Jovian planets would most likely enter a higher orbit. As stable as the whole system currently is, i'd be willing to bet that most (if not all) would simply enter unstable orbits and end up either getting flung into space, crash into the sun, or collide with one another. More specific details are beyond my scope.


    Perhaps someone on here has played around with an N-body simulation such as this?
  4. Sep 13, 2007 #3


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    The inner planets wouldn't enter tighter orbits. The outer planets wouldn't enter higher orbits. For the most part, nothing would change. The exception would be Jupiter's moons. Depending on where they are in their orbits, some would be on hyperbolic solar trajectories, and would leave the solar system.

    Subtle changes to the planets' orbits would occur over millions of years. Currently, the Earth's eccentricity rises and falls in 100,000 year and 400,000 year cycles. Since Jupiter is the primary cause of this, Earth's and Mars' eccentricities would be virtually frozen at their current values.
  5. Sep 13, 2007 #4
    So, Jupiter's absence of mass wouldn't be sufficient enough to produce a notable change in say, Mars's orbit?

    *edit* Nevermind Tony. Reread your answer. Never realized the perturbations were so small.
    Last edited: Sep 13, 2007
  6. Oct 13, 2007 #5
    Even over billions of years? I find that hard to believe.
  7. Oct 13, 2007 #6


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    Did you read the second paragraph of tony873004's response? "Subtle changes to the planets' orbits would occur over millions of years."
  8. Oct 14, 2007 #7
    I've read in many journals that there is evidence that Jupiter helps to keep too many asteroids and comets from wondering in the inner solar system, so I would imagine that if it were to suddenly disappear impacts would start to occur much more frequently.

    Other then that nothing much would change since all the planets are in relatively stable orbits.
  9. Oct 14, 2007 #8
    Maybe Neptune or Saturn would just take its place?

  10. Oct 14, 2007 #9
    Also, if all the planets were aligned on the same side of the Sun, the combined center of mass would lie about 500,000 km above the Sun's surface..this says a lot about how much the mass of the Sun dominates the solar system. The barycenter of the entire Solar System lies "just outside of" the photosphere.

    The loss of Jupiter, though huge with respect to the Earth's mass, seems trivial in comparison to the rest of the center.

    Just a thought,
  11. Oct 17, 2007 #10
    for one thing, the halleys comet would come to earth a lot quicker, as it wont suffer any retardation due to jupiters gravitational pull...
  12. Oct 17, 2007 #11
    I could be wrong here, but I highly doubt that the absence of Jupiter would have any effect on Halley's comet's velocity. As I posted in the previous post, Jupiter's mass seems negligible in comparison to the Sun's mass (around which Halley's comet orbits).

  13. Oct 17, 2007 #12
    dude, last time halleys comet was delayed by approx 520 days because of gravitational pull frrom jupiter and saturn...
  14. Oct 17, 2007 #13


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    Halley crosses the orbits of many of the planets. So it's much more capable of being perturbed than objects in nearly-circular orbits. Haley is also a comet, and outgassing that produces the tail we see also affects its orbit.
  15. Oct 17, 2007 #14


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    Do you have a reference for that? Perhaps it happened to pass unusually close to them...
  16. Oct 18, 2007 #15

    I don't think so. Gravity is much weaker due to the distance involved. Jupiter is not only the biggest planet in the solar system (about 1.5 times bigger than all the planets in the solar system combined),but the fact that it is close by compared to the others means that its orbit is smaller (making it much more likely to intercept an asteroid or comet, unlike Saturn) and it can actually have some sort of influence on the motion of the asteroids going in and out of the inner solar system. For one, impacts with Jupiter are estimated to be about ten thousand times more likely than impacts on Earth. The gravitational affects of the other planets are minuscule compared with Jupiter.
    Last edited: Oct 18, 2007
  17. Oct 18, 2007 #16
    You are wrong. If it was far away from Jupiter, then it's gravity would have negligible affect. But if it passed close by, then it could influence its orbit a great deal....

    You have to remember that the gravitational pull of the sun is very negligible at large distances, especially for an object traveling with so little mass (I think Halley's comet is about 2.2x10^14 kg, from what my sources tell me). Also, Halley's Comet has a very eccentric and elongated orbit, so it is not always the same distance from the sun, and it has a very low mass.

    If you do a rough calculation for the gravitational pull from the sun on Halley, you can find that to be approx 1.30x10^12 N when it is the same distance from the sun as Earth (the closest it can get is about .5 - .6 AU). Likewise, the gravitational pull from the Sun on Earth is much bigger (about 3.54x10^22 N).
    If Halley's comet were about, say, 4 million miles (about 6437376000 meters) from Jupiter, then the gravitational pull from Jupiter on Halley would be about 6.72x10^11 N, while from the sun (which from this point it would be about 5 AU from the sun) it would be about 4.83x10^10 N, an order of magnitude lower.
    Last edited: Oct 18, 2007
  18. Oct 19, 2007 #17


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    Even though the gravitational force on Haley is small due to Haley's small mass, Haley's small mass makes it easier for this small force to accelerate Haley. F=ma, therefore a=F/m. So let's just say for example that Earth is 1 tillion times more massive than Haley. a=1,000,000,000,000 / 1,000,000,000,000 is the same as a=1/1. This is why you can drop a big rock and a small rock from the same height, and they hit the ground at the same time.

    So even when Haley is at the same distance from the Sun as Earth, the Sun's gravity accelerates them equally.

    Here are the results of 2 simulations of Haley's comet. In the first simulation the masses of all the planets and Pluto are included. In the second simulation Jupiter is deleted. Both simulations run for 455 years, from 2007 to 2462.

    It's obvious from these images that Jupiter is by far the largest perturber of Haley's orbit. The changes in Haley's semi-major axis, which can be seen by looking at its aphelion (furthest point from the Sun) will have an effect on its orbital period. I would guess that 500 days is reasonable.
    Last edited: Oct 19, 2007
  19. Oct 19, 2007 #18
    I knew that, the reason for comparing the values was so that I could demonstrate the differences between the magnitudes of the forces acting on the bodies at certain distances.
  20. Oct 19, 2007 #19


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  21. Oct 19, 2007 #20


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    oops, sorry for the explanation then :smile:
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