Hang on tight : Speed of LIGHT!

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  1. Outlaw71

    Outlaw71 Well-Known Member

    Something else I was wondering... if you were driving along at night, at the speed of light with your headlights on... would you be able to see where you were going?

  2. wxman2003

    wxman2003 Well-Known Member

    You cant reach the speed of light. You can approach it, but not achieve it, so your headlights will work. :D
  3. Outlaw71

    Outlaw71 Well-Known Member

    HA! Try telling that to a beam of light why don't ya!

  4. Romoko

    Romoko Active Member

    If you're referring to a bike, then it's called "out-riding" your light. But it doesn't mean you're riding faster than the speed of light. It just means that you're riding faster than you can react due to your field of vision.
  5. TLDspectre

    TLDspectre Well-Known Member

    Not until you reach Alpha Centauri - and then you would have to stop and ask the Robinsons for directions...
  6. Outlaw71

    Outlaw71 Well-Known Member

    My only hope is that they have one of those signs... you know the one they place a little ways before a stop sign, warning you that there is indeed a stop sign up ahead so you can prepare yourself. I'd hate to have to slam on the brakes whilst traveling a few hundred thousand miles per hour!
  7. racinwarrior

    racinwarrior Well-Known Member

    terminal velocity of a car is just over 700 mph. not quite fast enough for acheiving the jump to light speed there Han Solo

    P.S. I know you were joking but i couldnt resist

  8. redifrogger

    redifrogger Well-Known Member

    I know this is off track a little (ok a lot) but the speed of light is exponentially higher than a few hundred thousand miles per hour. Try 186,000 miles per SECOND. That still boggles my mind. Or how about 671 million miles per hour!
  9. ricksievers

    ricksievers Well-Known Member

    I think yes, you will see where you were going. Its like a fighter jet shooting its guns, the speed of the guns are projected faster than at the speed its going than sitting still.
  10. redifrogger

    redifrogger Well-Known Member

    While I understand what you're saying, your analogy doesn't work, since nothing can exceed the speed of light. In fact nothing with mass can travel the speed of light. OK - I'm done pulling this off track. Sorry to contribute to this everyone.
  11. jcash3

    jcash3 Well-Known Member

    This may be the aerospace engineer in me, but where do you get 700 mph for the terminal velocity of a car? Unless your using a different meaning for the term, I assume that it means the free fall speed of an object once the downward force equals that of the upward force causing no acceleration.

    If I did my math right, that would be about 90 mph for an average car, if its falling front side down.

    Time to go back to the ADHD website
  12. racinwarrior

    racinwarrior Well-Known Member

    It's the maximum speed an object under acceleration can reach minus fictional, gravitational, wind, and mechanical friction. Mostly determined by the shape of the object.
  13. Stevessvt

    Stevessvt Well-Known Member

    Wouldn't that be mass of an object?
    (thinking to myself)
  14. GrandMasterB

    GrandMasterB Go Go Gadget Flow! VIP Member

    All discussions regarding the speed of light should be confined to this thread. Thanks to all who participate!

  15. eyebeam

    eyebeam Well-Known Member

  16. Outlaw71

    Outlaw71 Well-Known Member

    Are you certain of that? I remember learning that they originally developed the Blackbird as a fighter plane, but ended up removing the guns and missiles and turned it into a spy plane because it out ran all of the weaponry they had outfitted it with.
  17. dan330

    dan330 Well-Known Member

    1... yes.. airplanes been shown to out run thier own bullets and even shot by their own bullets!

    2. for the sake of this question... if the headlights could show you what is in front of you.. even up to 1000 miles head...
    WOULD IT MATTER????????????????
    moving at over 186k mps.. what the F--- would you see???
  18. DannyB

    DannyB Well-Known Member

    You are directly between two spaceships approaching you from opposite directions.
    Each spaceship is approaching you at 90% the speed of light.
    From either spaceship, what is the closing speed of the other spaceship?

    (Answer: less than the speed of light, but much higher than 90% the speed of light.)
  19. Thefoodman52

    Thefoodman52 Well-Known Member

    I would see...
  20. Stevessvt

    Stevessvt Well-Known Member

    If a plane was traveling the speed of light on a treadmill moving in the opposite direction at the speed of light....,
  21. Thefoodman52

    Thefoodman52 Well-Known Member

    The plane would travel in it's direction at the speed of light. Look up the physics, the wheels on the plane have no impact on the direction it'll fly in. A plane works by moving air under the wings to create lift, unlike how a car moves forward by relying on the wheels.
  22. Stevessvt

    Stevessvt Well-Known Member

    I know. I seen the mythbusters episode that conducted the experiment.
  23. EarlyMon

    EarlyMon The PearlyMon Moderator

    Fun with physics - here goes.

    Light isn't a speed per se - it looks like one - (approximately) 186,282 miles/second (aka - c - the speed of light).

    That looks like speed - like 80 miles/hour.

    But it's really a conversion factor. Just like 2.54 cm/inches changes your notation of length - 186,000 miles/second changes your notation from the 3 x, y, and z measures of a location in space to a location in time - or more specifically - spacetime.

    At speeds close to the speed of light, time changes compared to what you'd consider normal. We've all seen the hard-to-understand, but ever-popular, thing on the science channel where you hop in a spaceship and go near c in speed back and forth to some star - a few years pass for you while on Earth, your friends die off, and you come home to your grandchildren.

    Because you've left the more-space-kinda-spacetime and gotten closer to the more-time-kinda-spacetime.

    What about at the speed of light?

    Because the speed of light is a conversion factor - at the speed of light, there is no time with respect to space.

    We say that Proxima Centauri is about 4.3 light years away - light takes some 4 years to reach us from there.

    For the photons that hit us from Proxima Centauri - or any star or galaxy - no time has passed at all. For us, some 4 years passed - for the photons, no time has passed.

    At the speed of light, there is no distance in time - only distance in space. Time is instantaneous everywhere.

    So the first reason that you can't go faster than the speed of light is because you can't go slower than the speed of light. You're going to go at that speed through spacetime, because it's a conversion factor.

    This is why for all speeds below c, no matter how much or howlittle below c, the speed of light will always measure at about 186,282 miles / second. Just like 2.54 cm/inch is always true no matter how fast you go.

    Why can't you travel at the speed of light?

    When things move, they have momentum - move faster, more momentum - swing a hammer and you know it's true.

    So - news flash - E=mc^2 is not true - it's a popular fiction and a simplification.

    The real equation is E=mc^2/square_root(1 - v^2/c^2) where v is your speed - this accounts for that pesky momentum thingy while also calculating equivalent energy (E) of anything with mass (m). If you move at the speed of light, then v^2/c^2 becomes c^2/c^2 - which is one - and square_root(1-1) is square_root(0) which does not compute.

    So nothing with mass can travel at the speed of light.

    Photons can, because they have no mass.

    But - there's the solar wind and sci-fi books say you can build a solar sail and cruise in space that way. How so if photons have no mass? Because they still have momentum. Another rule they get to break, just like they break the time-standing-still rule.

    So, if your car were traveling at the speed of light - how much time would pass to see what's ahead?

    No time whatsoever - you're already simultaneously there while traveling there.


    PS - for a full discussion, see also - Amazon.com: Relativity Visualized (9780935218053): Lewis Carroll Epstein: Books
    SaleenFiend and Frisco like this.
  24. DaSchmarotzer

    DaSchmarotzer Blame it on me VIP Member

    What you are saying is absolutely correct, but E=mc^2 is actually true if "m" is the relativistic mass and not the commonly known mass, which is a vulgarization as you said.

    Cheers! :D
    EarlyMon likes this.
  25. EarlyMon

    EarlyMon The PearlyMon Moderator

    M-nought, m-nought, tastes great, wish I had some...

    You... are correct, sah!

    DaSchmarotzer likes this.

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