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How to Build a Time Machine

Posted by michael on from the mad-scientist dept.

frank249 writes "The September issue of Scientific American has an article discussing the possibility of time travel. They say that it wouldn't be easy, but it might be possible. It could be a while until we can expand worm holes and tow them to a neutron star but didn't someone say that if it is possible it will happen. If it is impossible it will just take a little longer."

2 of 456 comments (clear)

  1. Some Say it Has Already Happened ... by Crispin+Cowan · · Score: 5, Interesting
    If backward time travel is ever possible, then it has "already" happened. Someone has likely aleady travelled back before August 2002 and done something, we just don't know it.

    Of course, this induces the potential for paradox, causing great cosmological and philosophical consternation. I don't know what will happen if/when someone goes backwards through time, but here's some ideas:

    • The universe forks in two when a paradox is induced.
    • The universe forks in two at the instant the traveller enters history (because at a micro-level, paradox is induced as soon as they appear).
    • Paradox induces a cascading feedback loop of self-modifying universes (each inducing a time-traveller who goes back and causes another chage) until the sequence halts with a universe in which time travel is not developed. My bet is that if time-travel is possible, then this is what has happened, because there is no evidence of time travel.
    Forward time travel is of course possible right now, requiring only some patience :-) Accelerated time travel is also possible due to reletavistic effects and (possibly) cryogenics, allowing you to travel forward in time at some rate greater than 1 second per second.

    Crispin
    ----
    Crispin Cowan, Ph.D.
    Chief Scientist, WireX Communications, Inc.
    Immunix: Security Hardened Linux Distribution
    Available for purchase

  2. Re:The point you're missing is... by debrain · · Score: 4, Interesting

    I believe that travelling to the past would merely let us perform certain travelling at speeds faster than light.

    Or, put another way, the time required at maximum velocity to return to your point of origin is at least the amount of time you travelled back in time. I believe you must sacrifice time or sacrifice position.

    Position may or may not be in the way we expect; I suspect it is based upon your "depth" in the gravitational field, and as such, you would travel towards or away from heavy celestial bodies, such as the sun. Travelling towards them requires velocity. By the same token, you can temporally return to the beginning of the universe if you travel far enough away from the centre of it (assuming that the gravitational "depth" continues to decrease with distance, and the exponential energy increase required to travel as such is not unreasonable) ...

    Binary stars and other equilibrium comes to mind, but I conjecture that "free" time travel in perfect equilibrium would be impossible; your relationship with time can only be altered in respect to changes in the gravitational depth. However, they may have .. quirks of worthy pursuit.

    So goes a theory ...