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My idea for Space Travel

  1. Apr 16, 2008 #1
    Hi this is my 2nd post so pls be kind guys. Let me know of any other cool cosmology forums out there as they seem hard to find with google.

    So to my idea!

    Instead of waiting for some hyper-drive to be invented (I read of pushing spaceships with lasers?) how about we use our own star, the Sun, to travel to the nearest star with exoplanets that look capable of supporting life.

    The idea is to "push" our Sun in the direction of this star, which would take us along with it.

    I'm thinking massive nuclear explosions to divert our Sun off-course and in the direction we want to go. How viable do u think this is?

    I know we're 2/3 out of the Milkyway on a wing, and the centre of our galaxy is a compact source of radiowaves so theres a blackhole there that determines the course our Sun takes, but is this viable?

    Could we use our own Sun... say once its nearing the end of its life... to travel thru space?
  2. jcsd
  3. Apr 16, 2008 #2


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    Umm, no.

    For one, the sun is extraordinarily massive and it would take an unimaginable force to move it any substantial distance. Even the most destructive technology ever built doesn't even come close. Also, the sun was not designed to absorb any type of energy and convert it into motion. Nuclear explosions would simply give off a lot of high energy particles, which the sun probably wouldn't be able to turn into ANY type of motion.
    I believe Carl Sagan suggested a nuclear-based propulsion source which involves exploding high-yield nuclear bombs at the back of a space ship with a specially designed shield. However, this shield would have to be a) extraordinarily large b) extraordinarily durable. The sun has no such mechanism, so I doubt this would be effective.

    Also, by the time the sun nears the end of its life, we will either not be here, or exist in a form we cannot even begin to imagine.
  4. Apr 16, 2008 #3


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    No this is not viable. It seems like wild speculation to me.
  5. Apr 16, 2008 #4
    Thx for the response.

    I thought it was a good idea, and I know nuclear explosions wouldn't even come close as a destructive force - maybe dragging a blackhole in front of it would be a better analogy, something like this... :P

    I know most star-systems are binary so maybe we could join forces with another star this way.
    Last edited: Apr 16, 2008
  6. Apr 16, 2008 #5


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    I think it best to do a little research about the sun first before proposing an idea like moving the sun.

    The sun is already a giant thermonuclear furnace. It also has massive explosive events (Coronal Mass Ejections - CMEs) that dwarf anything mankind can produce.

    "As much as 1x1013(10,000,000,000,000) kilograms" or 1x1010 metric tons of material can be ejected into the solar wind.


    This site puts CMEs on the order of 100 billion kg -

    With regard to blackholes, one should try to find the location of where we believe a blackhole is located.
  7. Apr 16, 2008 #6


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    How would you move the black hole or other star in the first place? How would you protect the planets from gravitational perturbations that would alter orbits? Its not viable.
  8. Apr 16, 2008 #7
    Well if I recall there was the idea of a gravitational tractor of sorts. You place a massive object with propulsion near the sun and slowly set it off in the direction you wish for it to go. The object moves and due to gravity the sun moves with it.

    This of course is incredibly slow and takes a lot of energy anyways. But hey, if you're planning on moving a star then I'm sure you aren't doing so for fun.
  9. Apr 16, 2008 #8


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    Larry Niven uses something like this in his Hugo and Nebula award winner Ringworld. But what you might want to read is a short essay he wrote called "Bigger Than Worlds" where he explores Ringworlds, Dyson spheres, Dyson galaxies, and all sorts of interesting stellar engineering techniques.

    He imbues his Ringworld with superconducting material which puts the sun in a colossal magnetic bottle, causing it to lase. The resulting jet of plasma turns the sun into a rocket.
  10. Apr 16, 2008 #9


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  11. Apr 17, 2008 #10


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    I don't know about the rest of the article, but I'm making this my new desktop wallpaper.
  12. Apr 17, 2008 #11


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    There's something familiar about 1.21 Gigawatts. hmm :confused:
  13. Apr 17, 2008 #12
    "1.21 Gigawatts? 1.21 Gigawatts? Great Scott!" [picks up and talks to framed picture of Faraday is it?]

    "I'm sorry, but the only power source capable of generating 1.21 gigawatts of electricity is a bolt of lightning."
    [startled] "What did you say?"
    "A bolt of lightning!"

    "No, no, no. This sucker's electrical, but I need a nuclear reaction to generate the 1.21 gigawatts of electricity I need."
    "Doc, you don't just walk into a store and buy plutonium. Did you rip that off?"

    I always thought they said Jigawatt and not Gigawatt :D
    Last edited: Apr 17, 2008
  14. Apr 17, 2008 #13
    If you want to move the sun and the solar system along with it, the only way is to send something out of it. Efforts with rockets or atomic bombs are futile as long as the exhaust or vaporized rock doesn't leave the solar system.
    The best we could do at the moment would be to send some asteroid out of the solar system using atomic bomb explosions and a gravity assist from a planet.
    Unfortunately the escape velocity from the solar system is too high to do it from the earth, so apophis is 2029 won't do. We may be able to find an asteroid that is going to be close to Jupiter, and arrange a near miss and get it out of the solar system.
    of course the sun would still be at least a factor 10^15 heavier.
    We really have to push a planet out somehow to get anywhere.
  15. Apr 17, 2008 #14


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    Gravity assist won't accomplish anything. It steals energy from the solar system (by way of a planet's orbital speed) to launch the projectile. Net result on the solar system: a slight loss in energy, and no net movement.
  16. Apr 18, 2008 #15
    what about conservation of momentum? if an asteroid escapes with momentum p, the rest of the solar system will get a momentum -p.
  17. Apr 18, 2008 #16


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    Remember, the goal here is to get the SS moving.

    That energy you're imparting to the asteroid does npt cause an equal and opposite movement in the SS , it causes a change in the SS's internal moving parts.

    Firing an asteroid by gravity-assist will simply result in a SS with planet(s) that orbit slightly closer to the sun.
  18. Apr 18, 2008 #17
    Conservation of momentum is ALWAYS valid, so if you send something out of the solar system, the solar system itself will move in the opposite direction.

    I have to agree that almost all of the energy taken from the potential and kinetic energy of the planets will be spent on increasing the potential and kinetic energy of the asteroid, but this is inevitable, as accelerating a large mass M by throwing away a small mass m with speed v will give E_small = (1/2)mv^2 of kinetic energy to the small mass, and only (1/2)M(v*m/M)^2 = E_small*m/M kinetic energy to the large mass. (M>>m)
  19. Apr 18, 2008 #18
    is harnessing the power of a lightning bolt possible?
  20. Apr 18, 2008 #19


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    Nobody said it wasn't. But the SS isn't a single, solid object. There are ... options ... for conservation.
    Let's take it to the extreme to make it easier for me to grasp.
    You use all the energy in a planet's orbit to eject your asteroid. The planet falls into the sun. I don't see that the SS would move anywhere.
    Last edited: Apr 18, 2008
  21. Apr 18, 2008 #20


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    Consider it in terms of the barycenter of the Planet-asteroid-Sun.

    When you start, this barycenter is motionless. When you finish, this barycenter can not have moved to conserve momentum. But the position of the barycenter does change with relative to the Sun-planet barycenter and the center of mass of the asteroid.

    Imagine the asteroid moving to the left. Distance between the asteroid and the barycenter increases to the left, and the distance between the sun-planet and the barycenter increases to the right.

    Since the barycenter itself must remain stationary, This means that the Sun-planet pair must move to the right to compensate for the movement of the asteroid to the left.

    The Solar system will recoil from ejecting a body.
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