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Can You Travel Faster Than The Speed Of Light?

  1. May 15, 2008 #1
    This Question begs an answer and that is impossible but i'm sure we can agree on one 'unified answer'

    I Know from a lecture about energy needed to travel at the speed of light and found:
    E=(Gamma)Mo(Mass In A Stationary Postiton)C2 (Constant/Speed Of Light)

    Now according to this formula there cannot be an answer for 99.999999...%< as Gamma
    Gamma=√1-v2 (squared) V Is the index form of the speed of light 99%=0.99

    this 'supposedly' proves there cannot be a speed greater than or equal to 100% of the speed of light.

    could someone prove this wrong...?
    I will post another theorem with this to help justify both answers.
  2. jcsd
  3. May 15, 2008 #2


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    No, "you cannot travel faster than the speed of light."

    I think you should review the forum rules before you make any more posts, especially the part regarding "overly speculative posts."
  4. May 15, 2008 #3
    sorry :)
  5. May 15, 2008 #4
    Theorectical physics is, by inherent nature, speculative. But it also demands responsibility of factual foundation as a basis for the speculative.
    It is not enough to ask "what if", rather the demand is to base the "what if" on established facts or to persue a course of action to establish new facts for support.
    This is very difficult... best of luck.
  6. May 15, 2008 #5
    Correct me if I am mistaken:E=mc2 does not prove you cannot travel faster than light.I thought the fact that the speed of light in vacuum is constant(supported by experiments).So if a spaceship travels at c and has a headlight...an observer would measure the light beam and the spaceship to be at the same point(because the light beam goes at speed c and spaceship also goes at speed c).However,the speed of the light beam RELATIVE to the spaceship should be c.This contradicts the spaceship and the light beam being at the same point.And therefore we can never go at nor faster than the speed of light.
  7. May 15, 2008 #6
    actually, you can get as close as possible to the speed of light, but you cannot reach the speed of light in a vaccuum, because it would take an infinite impulse to reach the speed of light.
  8. May 15, 2008 #7
    The paradox you point is solved by time being relative. An observer would see the light moving forward just slightly faster than the spaceship. The time inside the moving spaceship moves slower so people on the spaceship would still see light moving at c.
    As matthias points, you need an infinite impulse to reach c as your mass is increasing with speed, and that's why is not possible to move faster than c.
    You can move faster than the light but not in vacuum.
  9. May 15, 2008 #8


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    Right; hence Cherenkov radiation. As I understand it, though, the equations rule out only an object with mass travelling at the speed of light. The speculation about the existence of tachyons was based upon the possibility of something having c as it lower speed limit.
  10. May 17, 2008 #9
    however if we found a state of essence that light could be slowed down in and propelled an item faster than this wouldn't that still create the same effects as this whole discussion is Based around E=γMoC2 where C is the speed of light in a vacuum if we change the C Variable into... say... Diamond Or excited gas where the light is slowed down then it would take a considerable less amount of energy to do this.
  11. May 17, 2008 #10
    In my dreams...
  12. May 17, 2008 #11


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    Just look at the stars and start spinning around on your feet.. you will observe the stars to move faster than c. My point is that things can travel faster than c if we aren't talking about inertial motion. What exactly is it you wan't to know?
  13. May 19, 2008 #12
    Velocity addition has no limit as it is a hyperbolic function. Pseudo-rotations in spacetime due to accelerations cannot turn from a timelike to a nullike path.
  14. Sep 16, 2009 #13
    Hello MeJennifer
    The first remark about velocity addition I understand a little; do you mean it is an algebraic property with parallel consequences in geometry on hyperbolic surface? But the second about fourdimensional knowledge; could you enlighten me a little more?
    greetings Janm
  15. Sep 16, 2009 #14
    No, you cannot do that. The equation is [itex]E=\gamma m c^2[/itex], and c is the speed of light in vacuum. It is perfectly possible for something to go faster than the speed of light in a medium, but never faster than c. When it does, the body releases Cerenkhov Radiation.
  16. Sep 16, 2009 #15


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    You guys are responding to posts from May 2008, the original posters probably aren't around any more.
  17. Sep 16, 2009 #16
    Oh well. My argument still stands ;)
  18. Sep 17, 2009 #17
    Hello ZikZak
    If you want to use an energy formula of v, it is not appropiate to use the one for total energy, but rather use:
    E_kin=gamma m c^2 - m c^2
    Note that v=0 implies E_kin=0 as it should.
    greetings Janm
  19. Mar 28, 2010 #18
    its ok :)
    oh wait, you wernt talking to me
  20. Apr 6, 2010 #19
    Ok. Your question is that can you travel at the speed of light? Well, i'm sorry, you cannot. According to Einstein's General Theory of Relativity, simplified, E=MC2, it is directly stated that nothing may travel at the same speed of light, especially in a vacuum, which is the circumstance in space.Yet, there is a speed that far exceeds this, where particles travel at 1/1000000000000000000000000000000000000, or 6 millionth of a second. However, there is a twist. This speed is impossible to achieve in space but SPACE itself travels at that speed. Though this is only theoretical physics, because these rates are only recorded in the Big Bang. Hope I helped a bit. :rofl:
  21. Nov 8, 2010 #20
    Let's suppose one cannot travel faster than speed of light but can travel "At" speed of light for the purpose of this speculation.

    Here's the scenario:

    Master Vader, after having won the Ultimate Championship of Golf on Earth, takes off in the Ultra Luxury Space Ship Lady Gaga at the speed of light towards Intergalactic Jedi Golf Federation Hall of Fame in Delta Quadrant.

    Half way through the journey he notices Kendomaster returning from exile in a Compact Space Ship Volt at barely attained speed of light towards Earth.

    Before Vader could say "hello" both space ships pass each other and are travelling at opposite directions.

    "That Kendomaster....he must not know the Ultimate Championship of Golf is over. Always late. Poor chap," thought Master Vader.

    Now. Both Master Vader's Ultra Luxury Space Ship Lady Gaga and Kendomaster's Compact Space Ship Volt are travelling at the speed of light. However, since they are travelling at precisely opposite direction each ship is traveling 2x the speed of light away from each other.

    Applying Einstein's Theory of Relativity, speed of a moving object must be measured from a point relative to it's previous position to be exact. But that measured speed only applies to the moving object itself and not to any other object outside of it.

    From Kendomaster's point of view Vader is moving away from him at 2x the speed of light. And vice versa.

    To answer the quesion, "Can you travel faster than the speed of light?", the answer is no according to the equation. However, you can be traveling away from another object at 2x the speed of light if the other object is also traveling at speed of light in opposite direction.

    So the ultimate rule in space travel seems to be that no two objects can move away from each other faster than 2x the speed of light, relative or not.

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