Speed of light and time

Discussion in 'Science and Nature' started by Smittyben12, Nov 22, 2010.

  1. I've been told light is instantaneous and that when you reach the speed of light that time literally stops for said person. But light travels at 186 thousand miles per second. So my question is. If it takes time for light to reach us (ie lightyear) then why would time stop at the speed of light? It seems to me that if time really slowed to a stop at the speed of light then we would not have a speed becouse it wouldn't move it would take up all the space from point a to point b without taking anytime at all. Please don't just say " theory of relativity" I know what that is. Thanks:smoke:
     
  2. Light isn't instantaneous.

    c = 2.998 x 10^8 m/s
     
  3. ^did you reed the post? I said that
     
  4. time doesn't stop at the speed of light
     
  5. It's been proven the faster you go the slower time moves for you.....
     
  6. #6 adambommb, Nov 22, 2010
    Last edited by a moderator: Nov 22, 2010
    so are you going to post some references? or are we supposed to take your word on that...
     
  7. for some reason i thought your post said something else... disregard, im familiar with relativity
     

  8. I'm well aware of c btw I passed sophomore chemistry Lambda= c/v
     
  9. Time would appear to stop to an observer at the speed of light, as the only reference you have of time moving forward, is light reflecting off of objects and hitting your eye, and if you were moving at the speed of light, there would be no light bouncing off your eye, you would be traveling at the same speed of it, so things would seem to have no time. Your body would also probably heat up to a billion degrees if it was to pass through anything of any mass... like a cloud of dust would destroy you..... hahahaha..... Like sand moving in high winds can fuck a person up, i can only imagine slamming into a cloud of gas in space at light speed.....
     
  10. Time is relative. Time on Earth, is not the exact same off Earth. I beleive mass has an effect on time.

    GPS sattelites have perfect time until put in space. In orbit they go off by a fraction of a second everyday. The onboard computer corrects this. If it didn't your GPS location would be off by over 6 miles.

    I know its something very difficult to comprehend. I still have trouble wrapping my brain around it. But, time is relative.
     
  11. Ya less relative gravity more time and more speed slower time I just find it odd that speed and time are intertwined space-time I guess:p
     
  12. #13 sikander, Nov 23, 2010
    Last edited by a moderator: Nov 23, 2010
    In any frame of reference, moving or otherwise, an observer will observe light traveling in a vacuum to travel at c relative to themselves. If you're stationary, and I'm moving at, for the heck of it, 0.5c, each of us will record the light to be moving away from us at around 186,000 miles per second relative to our own frame of reference (as if we were stationary).

    This means: either the light-beam is traveling at two different speeds at the same time, or, b) you and I are experiencing time differently. Einstein demonstrated it was the latter. The exact equation governing how differently we'll experience time based on our relative velocities isn't that difficult, but would be annoying to describe here. The upshot is that as the velocity of something relative to you increases, it appears to move more slowly (time passes more slowly for it).

    As you approach c the time difference approaches infinity (it gets closer and closer to completely stopped). At c, the time difference would be infinite (it'd be stopped), but due to certain practical considerations (mass increases as well, verging on infinity as well; photons are massless so aren't constrained by this, but matter is. Infinite amounts of energy don't exist, so the energy required for something with mass to move at c is unreachable) this state of affairs for anything other than photons is basically impossible.

    EDIT: The key is relative velocities and relative observed times. Motion is not absolute; it has to be in reference to something. Ideally there's be some kind of universal reference frame we could use to gauge all motion by, but there simply isn't. All you can say is that relative to a certain reference frame (say, yourself) something is moving. Relative to that something's reference frame, however, you're moving. There's no meaningful difference.

    The light is still moving at c relative to you, and always will be no matter how fast you're moving.
     
  13. #14 illadelphin, Nov 23, 2010
    Last edited by a moderator: Nov 23, 2010
    notice the PER second. speed is the magnitude of velocity, being the change of some distance over an amount of time.

    light would still have a velocity, but if you said the change in time is 0.. then it's instantaneous change of distance would be zero over zero seconds...

    if you don't want us explaining relativity, why 'ask' this question?

    time doesn't 'stop' at the speed of light. time is time, it is a change. SOL is the fastest known moving particle in the universe, so it is our upper limit of known reference velocities.


    edit: don't read this. sikander makes us all look stoopid.
     
  14. Haha... wow...

    I should cut down on the day drinking. Sorry.
     
  15. #16 fatkat, Nov 23, 2010
    Last edited by a moderator: Nov 23, 2010
    We don't really experience time differently at different speeds, rather the rate of the passage of time changes for us :)

    I think you had this in mind but I had to read your post a couple times to understand you weren't saying that moving faster actually makes us experience the difference in the rate of time.

    We don't start experience ourselves moving in slow motion as we approach c. An outside observer would see us apparently moving in slow motion if we were moving close to c but we wouldn't 'really' be moving in slow motion - at least not from our frame of reference. I think that's an important distinction.

    Also if we could somehow travel at the speed of light, would we 'experience' time actually stopped? I don't think we would (I'm not sure) but to an outside observer it would appear that we were freeze framed.
     
  16. To all the people saying that what you see would change that at c we would stop becouse we would see a frozen image relativity says that our whole body and being would stop. We would not age we would not think we would not move (relative to our spaceship) yet we would spend the rest of our lives in one single instant. Meanwhile life on earth would go on just as it does now. Wait what was my point...... Time "traps you" in a single instant light has nothing to do with time there could be no light or a great light it is simply the speed of light (c) that effects time and speed in general.
     
  17. If mass has an effect on time, if you lived on a larger planet, would time be faster or slower?
     
  18. Sorry. I was trying to say that we would experience the apparent time of the moving thing to be different. What we thought took 1 second would appear to take 2 seconds over there. But it's tricky. For the moving thing, what appears to take 1 second there would take 2 seconds here. Motion is relative, so is time. You can't make an absolute pronouncement on it, just observe how fast it appeared to be going at a given time.
     

  19. gravity is what actually does the affecting. Time would appear the same speed tho. As you are within the time being influenced.
     

Share This Page