Swimming in Space

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Captain Kremmen, Jul 1, 2007.

  1. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    If an astronaut was floating freely in space, presumably any motions made would cause movement, equal and opposite. For example, a sweep of the arm should cause spinning, and movement away from the direction of the sweep.
    Now here's the question. Would it be possible for astronauts to manouvre themselves in a deliberate way and reach a desired destination?
    There is of course nothing to push against, as with a swimmer in water, so their technique would have to be different.
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Read-Only Valued Senior Member

    Messages:
    10,296
    Nope, wouldn't work at all. Action/reaction is true enough but first you have to have something to act with. If it's truly empty space (no slowly moving rocks floating by or a tank of compressed gas with you, you're simply stuck - no matter how much flailing around you might do.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. devire Registered Member

    Messages:
    79
    were u planning on swimming to the moon? lol.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    Read Only:
    You would act using the energy in your own body. Do rockets not work in space?


    Devire:
    That's not a bad idea. Planet to planet swimming competitions.
     
  8. (Q) Encephaloid Martini Valued Senior Member

    Messages:
    20,855
    The rocket propels mass out, which is the action/reaction, the body does not.
     
  9. Read-Only Valued Senior Member

    Messages:
    10,296
    As Q just pointed out, and as I said earlier, you need something to push against. A rocket does that by pushing against it's reaction chamber or you could toss rocks - like I said - if there were any handy.

    Why do you suppose spacewalkers use tether cables and all scifi movies have them wearing jet-packs?

    Please Register or Log in to view the hidden image!

    Use all the body energy you like - action/reaction first requires there be something to perform the action on. In empty space there is nothing.
     
  10. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    Try this scenario. You are floating in space. Wiith your right arm stretched in front of you with your fist clenched. Using the muscles in your arm, you contract your arm and strike yourself in the chest. Firstly, Will you feel it? (Pretend you don't need a space suit)
    Secondly, will it cause any movement or rotation? Why would this mass, your fist, driven by your muscle strength, be different from a rock striking you.
     
  11. Smellsniffsniff Gravitomagnetism Heats the Sun Registered Senior Member

    Messages:
    364
    The momentumvector does not change direction from inner movement, the energy preserves its p*angle at all times. Even if the mass divide into 2 masses or one mass moves itself. Even though some mass can be transported and turn into kinetic energy and then momentum later on, but momentum that has 2 directions.

    All momentum caused by energy has a vector sum that is 0, and atleast 2 opposit directions.
     
  12. orcot Valued Senior Member

    Messages:
    3,488
    Perhaps you could somehow use the earths magnetic field... it gives something to push against, without ejecting mass
     
  13. Janus58 Valued Senior Member

    Messages:
    2,394
    yes
    It is different for the very rreason that it is driven by your own muscles. As you contract your fist towards your body, their is a action-reaction connection that causes the rest of your body to move towards your fist. Whn your fist strikes your body, those two motions (fist toward body and body toward fist) cancel each other out and leave you with no net motion.

    And though different parts of you(body and fist) do move during this exercise, your center of mass never moves.
     
  14. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

    Messages:
    8,967
    Actually, since space isn't a perfect vacuum, you could swim, just not very quickly.
     
  15. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    Nicely Put.
    Drifting in space must be very frustrating.
     
  16. iceaura Valued Senior Member

    Messages:
    30,994
    If there were some way to eject mass, you could move.

    A properly set up suit mechanism, and a diet of beans ?
     
  17. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    With a supply of snuff, you could sneeze yourself almost anywhere.
     
  18. mybreathyourlung Registered Senior Member

    Messages:
    152
    Sadly, you'd still require a spacesuit so a diet of beans and snuff would make for a messy space-travel scenario.

    Speaking about using the Earth's magnetic field, would it be possible to orbit the Earth using the magnetic field if you were attached to a big enough magnet?

    Also, with this deal of objects orbiting the earth and slowly falling back to Earth (satellites, mostly) and burning up, why don't they just equip these expensive pieces of equipment with something to slowly propel themselves back into their intended orbit?
     
  19. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    MBYL:
    Messy yes, but imagine it. A tin of snuff, a few cans of beans, and you could go anywhere you liked. You'd be King of Space!

    Anyone:
    Would this go for a spaceship powered with a nuclear reactor as well. Could it not use any of that huge amount of energy to actually move anywhere?
     
  20. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

    Messages:
    2,559
    Chris:

    Ya gotta have thrust. Gotta throw mass in the opposite direction you wish to travel.

    Try taking off your helmet, and throwing it.
     
  21. Jeff 152 Registered Senior Member

    Messages:
    364
    the way to do it is to throw a space boomerang that works even in a vacuum so when you throw it you move and then when it comes back and hits you it moves you again. Go anywhere in half the time!

    *kidding...
     
  22. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    Everything you do just neatly cancels itself out.
    What a nightmare!
     
  23. Read-Only Valued Senior Member

    Messages:
    10,296
    Well, not really. You just don't have anything to interact with.
     

Share This Page