These are based on Theoretical Physics.

We can achieve 90% of speed of light but reaching 100% is not possible.

Till now nothing is found which can travel faster than light.

But in 1994, a Mexican physicist, Miguel Alcubierre, theorized that faster-than-light speeds were possible in a way that did not contradict Einstein.

His theory involved harnessing the expansion and contraction of space itself. Under Dr. Alcubierre’s hypothesis, a ship still couldn’t exceed light speed in a local region of space. But a theoretical propulsion system he sketched out manipulated space-time by generating a so-called “warp bubble” that would expand space on one side of a spacecraft and contract it on another.

“In this way, the spaceship will be pushed away from the Earth and pulled towards a distant star by space-time itself,”.

But Dr. Alcubierre’s paper was purely theoretical, and suggested insurmountable hurdles. Among other things, it depended on large amounts of a little understood or observed type of “exotic matter” that violates typical physical laws.

Reference: www.nytimes.com/2013/07/23/science/faster-than-the-speed-of-light.html

Regards:

Nitish

Vijaykumar,

Indeed, the Special Theory of Relativity, backed by a great deal of experimental evidence, suggests that no object with mass can be seen to travel at the speed of light.

An object with mass, when accelerated, appears to become harder to accelerate.

You can treat this as an increase in its mass.

At ever-higher speeds, the object becomes ever harder to accelerate, without limit.

There is, however, nothing to stop an object from travelling *faster* than c, but you have to then accept that such an object would have imaginary mass (ie, its square is negative).

There is no evidence for such classes of objects.

http://en.wikipedia.org/wiki/Tachyon

According to Einstein's General Theory of Relativity If an object moves faster, its mass increases and its length contracts. At the speed of light, such objects will have an infinite mass, while its length will become 0(zero), which is impossible. Thus, no object can reach the speed of light.

Regards:

Nitish

Let's start with the basics: It is not good to introduce the concept of the mass M = m / sqrt(1 - v^2/c^2) of a moving body for which no clear definition can be given. It is better to introduce no other mass concept than the ’rest mass’ m. Instead of introducing M it is better to mention the expression for the momentum and energy of a body in motion. — Albert Einstein in letter to Lincoln Barnett, 19 June 1948 (quote from L. B. Okun (1989), p. 42[1])

The internal structure of particles does not change in any way when they travel with constant speed, and hence it makes no sense to attribute a different mass to them. Explaining that you can not travel faster than the speed of light because you will be infinitely heavy does therefore not answer the question. Furthermore, if solving relativistic equations of motion is your daily job, as is mine, the concept of relativistic mass does not make your life easier. Not at all. If someone would insist on a simple explanatinon I would settle for "The Lorentz factor is part of the equations of motion, and as a consequence you need an infinite amount of energy to reach the speed of light".

But let's not spoil all the fun. There are 'things' than actually can travel faster than the speed of light. For example the light of a lighthouse can sweep faster than the speed of light given sufficient distance. But thats too simple to be interesting. Intellectually far more challenging is the concept of quantum entanglement. If you are interested in the combination of 'faster than light' and 'proven to be true' this is your field. But I have to warn you that 'what it is' that can travel faster than the speed of light is not easy to understand.

I believe that the "fuzzy" answer is that you cannot transfer "information" (which includes physical objects). between two points faster than light in a vacuum. (even using wormholes and the like). If you do, then there exists a frame (say a rocket moving relative to those two points), where the information is received before it is sent. This violates "causality" - again being fuzzy, but it would allow "causes" before "effects". Using two of these setups, you could transfer information into your own past.

If you can violate causality, much of the way we think about physics breaks. That doesn't necessarily mean it is wrong, but it is very difficult to figure out how to approach doing physics in a world where causality doesn't work.

So a lighthouse beacon doesn't transmit information between two points it hits - so it can sweep faster than light. Faster than ligtht particles could exist, but they can't interact with normal matter at all - so they would not be observable. Invisible parts of the universe can expand faster than light because they don't transmit information. Wave functions (might) change faster than light, but they are not directly observable - none of the measurements based on wave functions can travel faster than light. etc.