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Fleeing earth at the speed of light

  1. Mar 18, 2005 #1

    Pengwuino

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    Ok i was wondering something. Whats the closest planet/moon capable (possibly with human interevention) of supporting life that isnt in our solar system? And If you age slowely nearing the speed of life, wouldnt we be able to leave our solar system and reach another planet if we can go near the speed of light (and we'd age much slower so we could actually live out journey)? I know mass has to go incredibly high but its just a mental excercise :)
     
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  3. Mar 18, 2005 #2

    Integral

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    We have only begun to find other planetary systems in the last few years. There is virtually NO information about conditions on any of the planets found. So the only answer to your question is "We do not know".

    and NO! Your mass would not change if you imbarked on a high speed interstellar journey.
     
  4. Mar 18, 2005 #3

    Pengwuino

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    Well i meant if we did find one and had to leave Earth and we sent over equipment to sustain life and all that. My main focus on would we make the journey in only a few years of our time even though it might be millions of light years away?

    And why does everyone say as your speed -> c, mass - inf.
     
  5. Mar 18, 2005 #4

    SpaceTiger

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    I think it would be the most cost-effective to colonize Mars. In terms of other habitable planets, however, my guess is that they wouldn't be that far. I would be very surprised, however, if we found one nearby capable of supporting us sans equipment.
     
  6. Mar 18, 2005 #5

    Integral

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    Because they do not understand Relativity?

    Suppose you were in a space ship accelerating away from the earth with a known constant force applied. To a stationary observer on earth using the Laws of Newton, the ship's acceleration would appear to be reduced as it neared the speed of light AS IF ITS MASS were increasing. In fact the occupants of the ship may have been on a forced diet and actually lost mass as the journey progressed. The crew of the ship would not experience any reduction in their acceleration nor any change in mass nor would the operation of thier lights change. They would note, however, that the Earth was not receding as fast as NEWTON would predict for their rate of acceleration.

    The answer is that for relative velocities between 2 objects Newtons laws loose accuracy as you exceed a separation velocity which is a measurable fraction of c. At separation velocities greater then about .1c you must use the Lorentz transforms to correctly surmise the distance traveled.
     
    Last edited: Mar 18, 2005
  7. Mar 18, 2005 #6

    JesseM

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    Yes, in theory. See the relativistic rocket, which talks about how much time it would take to reach various destinations for travellers on a ship accelerating continuously at 1G--for example, it would take 3.6 years to reach the nearest star, but only 20 years to reach the center of the galaxy, and 28 years to reach the Andromeda galaxy. But accelerating for this long would be pretty much impossible if you had to carry the fuel onboard--the section of that page titled "How much fuel is needed?" explains why (for example, it says that to get to the center of the galaxy with a 100% efficient rocket, accelerating for the first half of the journey and then decelerating for the second half, you'd need 955,000 tonnes of fuel for every kilogram of payload mass, with 1 tonne = 1000 kilograms). It might be possible to scoop up interstellar hydrogen to use as fuel instead of carrying it on the ship--this idea is known as the Bussard ramjet.
     
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