Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Space time question

  1. Feb 19, 2007 #1
    keep in mind i am just an average highschooler who likes to read, but i was just wondering about something that i couldnt find in books or the internet. i know that the speed of light is 186,390 miles per second, so in turn you would have to travel that many miles to "go" back in time one second. but wouldnt that only be the case if you were on a level plane of time? i guess my real question is that if you were standing on a black hole, would that one second be much much closer due to gravity bending time? i hope that made sense enough for you to clarify for me. thx.
  2. jcsd
  3. Feb 20, 2007 #2
    It would be impossible for anyone to travel back in time. Time is not continum. And even if it were you would have to travel double the speed of light, mabey even triple just to travel back in time. Travelling 180,000 miles per second won't even get you anywhere probably one second in the futuer and even then it would still take you eight minutes to travel eight minutes to travel just 9 TRILLION MILES!

    If you were even near a black hole, much less just a few hundread trillion miles away you would still be sucked into oblivion. And on top of that Gravity bending time would create a wormwhole. Which is why a straight line isn't the shortest distance between two pionts it would be a wormwhole (the cloest to time travel you'll ever get.)
  4. Feb 21, 2007 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    c=299792458 m/s to be exact.

    You can't go back in time by traveling in space (at any speed), but maybe you just meant that if you look at an object at that distance you see it as it was a second ago.

    Did you mean "only if you're in a region of space-time that's flat"? In that case, the answer is no. The speed of light is always c.

    The answer is probably no, but I'm not sure I understand the question.
  5. Feb 21, 2007 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    It is in general relativity, which is still the best theory of gravity we have.

    Even if you could travel faster than c, you still wouldn't be able to go back in time. The weird thing that would happen is that in some inertial frames you would be seen to do everything in reverse order. For example, the end of your trip would occur before the start.

    Not necessarily. To create a wormhole you have to change the topology of space-time, not just the curvature.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Space time question
  1. Space-Time Questions (Replies: 9)