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Restructuring of the solar system theory

  1. Nov 10, 2009 #1
    Is it possible to move the planets Mars and Venus from their current orbits to ones more likely to support life, or at least have liquid water on their surface. The only idea I can imagine is to "steal" moons from the gas giant planets and put them on a path to be captured by the gravity of the object planets, and at the same time causing the necessary acceleration of their orbits to allow basic terraforming. This might just be crazy, but people thought Tesla was crazy too.
  2. jcsd
  3. Nov 10, 2009 #2


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    There's nothing particularly impossible about it at all. The energy required for such endeavors is undoubtedly orders of magnitude larger than the human race can provide at the present time, though. Such concepts have been around for quite a while and science fiction authors have not hesitated to use them (my mind drifts immediately to Olaf Stapledon's Starmaker).
  4. Nov 10, 2009 #3
    Wow, so I'm not crazy. There must be a way to produce such energy, I guess it wont be until antimatter is readily available that such things can be attempted. BTW is Starmaker a good book to read?
  5. Nov 10, 2009 #4


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    If you like Stapledon's style of writing, then definitely. As with all of his work the prose can get to be a little heavy at times, and you might feel like it drags on a little longer than necessary, but overall I liked it a lot. Well, except for the glaring scientific errors but it was written like pre-1940, so I can't really blame him that much for some of those.

    As far as the original post is concerned, why do you think you need a moon? I know our moon has played a fairly important role in the development of the current life-supporting conditions we experience here on Earth, but that role was played over geological time scales. I'm not sure what good having a moon will be other than something pretty to look at if you're only planning on scales of millions~100s of millions of years.

    The real biggie is how to move a planet to a different orbit without physically strapping rockets to the planet and blasting away for a very long time. It may be conceivable to redirect large asteroids/comets such that a close encounter with a planet robs it of a bit of its orbital angular momentum, which would tend to lead to a radial increase in the orbit. However, my celestial mechanics is a little fuzzy so I'm not sure if this will work and if so how effective it would be given asteroid sizes and planet masses (I'd guess bloody ineffective, though).

    Altering the atmosphere is probably a cheaper and more feasible alternative. This way you can take advantage of the greenhouse effect and attempt to use what energy is derived from the sun at a given radius to achieve a desired temperature. Another annoying thing you have to think about though is the fact that some planets rorate pitifully slow compared to the Earth (for example, Venus' day is something like 240 earth days). This creates an enormous temperature differential between light and dark sides, which would obviously be a problem for any building enterprises.

    There are a ton of other things you can think of, all you really need is basic basic physics and imagination. Nobody's fleshed this out in much detail, so you can pretty much propose whatever you want!
  6. Nov 11, 2009 #5
    Well it would be easier to move a moon of smaller mass and with less gravity pulling on it then it would be to move a planet.* But if the planet were to capture a moon, it would allow the rotation to be increased to better suit life.* The increase in rotation along with the introduction of water to the surface should take care of the temperature difference problem.* But if large amounts of nuclear weapons were to be fired at precise locations at certain timed intervals, then over a period of time could the desired effect work.*
    ********* When the moon has escaped the gravity of Jupiter its trajectory and velocity will be passed along to the other planet as they begin to react to each others gravity and be tugged into proper orbits.* From this point terraforming could begin.*
  7. Nov 12, 2009 #6
    Much easier merely to position big mirrors or shades in the right location to change the light levels reaching the planets. Or put a shell around them with a variable albedo and adjust accordingly. But if you really do want to move a planet then you need to read Paul Birch's papers on the technologies required...

    http://www.paulbirch.net/MoveAPlanet.pdf" (0.4 MB pdf)

    and his home-page stocks a lot of other papers worth reading...

    http://www.paulbirch.co.uk/" [Broken]

    ... since the 1980s his papers have basically defined the possibilities for large-scale planet-crafting. Two of direct relevance...

    http://www.paulbirch.net/TerraformingMarsQuickly.pdf" (1.7 MB pdf)

    Terraforming Venus Quickly
    (1.8 MB pdf)
    Last edited by a moderator: May 4, 2017
  8. Nov 12, 2009 #7
    I read this rather disturbing paper that was just posted on the arXiv...
    "[URL [Broken]
    An Overview of the 13:8 Mean Motion Resonance between Venus and Earth[/URL]

    ...which describes very rapid (~Myr) scenarios in which the eccentricity of the planet Mercury is chaotically amplified, sending it careening past the orbits of Venus and Earth. Venus's inclination needs to increase to only 7o for Mercury to start getting pumped up in eccentricity.

    Thus you might be able to trigger some interesting interactions between the planets by just tweaking their orbits a wee bit.

    BTW someone mentioned Olaf Stapledon's "Star Maker" and his discussion of "planet-moving". He uses it in an earlier book too, "Last and First Men" which is about human evolution over 2 billion years. In about 2 billion AD the last species of Man uses a planet drive to slowly spiral Neptune away from the Sun after it begins brightening due to a collision. Stapledon's astrophysics is old and his nucleophysics is SF hand-waving, but they're both good stories. "Star Maker" is the history of our Universe over billions of decades. In both books planets get moved by gigantic mass-annihilation (sub-atomic energy) drives. He was writing before antimatter was even imagined by Dirac, let alone detected, so he was merely using a common SF trope from the time.
    Last edited by a moderator: May 4, 2017
  9. Nov 12, 2009 #8


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    Ah right! I forgot he uses it there too! Unfortunately, it serves the men much worse than it served the species of Star Maker!
  10. Nov 13, 2009 #9


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    I'm pretty sure that replacing the entire atmosphere, then changing the rotation speed is bound to be orders of magnitude more energy-efficient than moving the planet to a new orbit. Anybody want to do estimate how much energy replacing the Venetian atmosphere would take?
  11. Nov 13, 2009 #10
    I'm sure the Venetians quite enjoy their atmosphere, aside from the occasional stink of the canals.
  12. Nov 13, 2009 #11
    Well they were moving Neptune and the Sun did brighten quicker than they expected. Psychologically the Last Men couldn't handle interstellar travel - the few brave souls who tried went kind of nuts, thus the Solar System couldn't be evacuated.

    Arthur C. Clarke sets about moving a large planet, Sagan II, in "The Songs of Distant Earth". The time frame he quotes might be excessively "quick"... about 25 years to change eccentricity, then 30 to circularise. The problem was that the crushing force of the Zero-Point Drive producing enough thrust to do the job would've buried the drive rather deep down in the body of the planet. To move a planet requires a more spread out application of forces.
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