can you, or can you not, travel faster than the speed of light?

[macbeth91]

got a problem. me and my friends are always arguing about the said title's question. i'm always the only one left fending for my thoughts on not being able to. problem is, i'm not a physics student, and my friends are. i tell them that the speed of light stays at a constant. its like, you can reach the speed of light, but it will always be the exact same speed faster than you. need help. i dont want help in arguing my point, but want to know what you people think is the right answer and why.

[Edtharan]

Acceleration = Force / Mass

 

But as you approach the speed of light you mass increases towards infinity (if you were to reach the speed of light your mass would be infinite).

 

So what is a finite (force) divided by Infinity (mass)?

 

This means that no matter how much you accelerate, you can never reach the speed of light.

 

but it will always be the exact same speed faster than you.

This is true for your own frame of reference, however, someone in a different frame of reference would see your speed getting close to the speed of light (but as it would take an infinite amount of energy to accelerate you to the speed of light, you will never actually reach it even from another person's frame of reference).

[Mr Skeptic]

Not normally. But you may be able to cheat and use a wormhole. Then you could travel faster than the speed of light as compared to outside the wormhole, though locally you would be traveling below the speed of light.

[dirtyamerica]

If you used a wormhole wouldn't your velocity still be less than c but space/time warped in a way that you got there sooner as if you actually went faster than c? In other words, you'd be perceived as getting to your destination faster than light by onlookers but as you travel through the wormhole wouldn't you be traveling slower than c?

[Sisyphus]

Just curious, what arguments do your friends use to say you can go faster than light?

[Klaynos]

I don't really like any of the above replies

 

Massless particles move at the speed of light relative to any inertial reference frame.

Massive particles move at less than the speed of light relative to any inertial reference frame.

 

The traditional way of explaining this is, as your velocity tends to c, the energy required to accelerate tends to infinity, the momentum also tends to infinity.

 

This can be seen in the equation:

 

E²=(mc²)² + p²c²

 

This in most physicists who work with relativity (especially theorists) is far preferable to using relativistic mass, it tends to be simpler to say there is only one mass, which is a Lorentz invariant and then you have Lorentz variant momentum and energy, as opposed to having all 3 variant.

 

There are some alternatives, group velocities in waves, and shadows, but in both of these information travels at or slower than c.

[DJBruce]

Under normal circumstances it is impossible to go faster to the speed of light because as you approach the speed of light your mass becomes infinite. But if you could some how create a worm hole or Rosenberg bridge you could go faster than the speed of light. But this is very improbable

[Klaynos]

Under normal circumstances it is impossible to go faster to the speed of light because as you approach the speed of light your mass becomes infinite. But if you could some how create a worm hole or Rosenberg bridge you could go faster than the speed of light. But this is very improbable

 

The mass increasing argument sucks Energy and momentum are far nicer

 

Rosenberg bridges and wormholes are currently outside mainstream physics

[iNow]

Rosenberg bridges and wormholes are currently outside mainstream physics

 

And according to this link that Martin shared a while back, may not even be possible:

 

 

http://www.scribd.com/doc/3366486/SelfOrganizing-Quantum-Universe-SCIAM-June-08

 

"Although such phenomena have never been observed, physicists have speculated that wormholes might fnd a justifcation within the still unknown theory of quantum gravity. In view of the negative results from the computer simulations of Euclidean quantum gravity, the viability of wormholes now seems exceedingly unlikely. Wormholes come in such a huge variety that they tend to dominate the superposition and destabilize it, and so the quantum universe never gets to grow beyond a small but highly interconnected neighborhood."

[macbeth91]

Just curious, what arguments do your friends use to say you can go faster than light?

 

my friends said: "ages ago, people said it was impossible to fly. when they achieved flight, people said it was impossible to travel faster than the speed of sound....etc":doh:

[insane_alien]

those were technological barriers rather than physical barriers though.

[swansont]

my friends said: "ages ago, people said it was impossible to fly. when they achieved flight, people said it was impossible to travel faster than the speed of sound....etc":doh:

 

Which are statements either taken out of context, or are poorly thought out. Birds fly, ergo flight is not impossible. Travel faster than the speed of sound was along ago observed with supersonic projectiles, so again, not impossible. What was being observed were the engineering difficulties, not ones imposed by physics, as insane_alien has pointed out.