 ## Why traveling at the speed of light is theoretically impossible

• • 6

If something has taught us ‘Star Wars‘ the thing is Going at the speed of light is not easy. Han Solo, in fact, is clear when he warns that “traveling through hyperspace is not like taking a walk in the countryside.” And it is that, despite the fact that in the well-known movie franchise they jump at the speed of light like the one that changes from second to third in the car, the truth is that, in practice, on a day-to-day basis, it is not So easy. Not to say that it is theoretically impossible.

There is a lot written about this and, on this occasion, we are not going to get into mathematical formulas and complex things. We are going to explain why, as far as science, mathematics and physics know, it is impossible to reach the speed of light. To do this, we have to understand something relatively simple, and never better said: the well-known formula E=mctwo.

## Einstein already warned us: we are doomed to be slow

Albert Einstein is a scientist who needs no introduction. One of his great milestones is the theory of relativity, and, for the case at hand, the theory of special relativity, whose formula is known to all: E = mctwo. In this formula, which is the equivalence between mass and energy, we find three main components, which are:

• AND: Energy.
• m: the mass of an object.
• c: the speed of light, which in the formula is squared.

The speed of light in a vacuum is 299,792.458 kilometers per second, although it is always said that it is 300,000 kilometers per second to approximate and that is the same as saying 1,080,000,000 kilometers per hour. Amazing, plain and simple.

And what does this formula tell us? That the energy can be calculated by multiplying the mass by the speed of light squared, that is, that when there is mass, there is energy. Even a relatively small object at rest, that is, not moving, has a generous amount of energy. Christophe Galfard gives a very good example in his book ‘The universe in your hand’ (21.85 euros): if we could transmute the mass of a 70-kilogram person into energy, we would get the same energy as 210,000 Hiroshima nuclear bombs.

Now, the formula we have used so far considers the energy at rest, that is, it is not complete. To complete it and discover why we cannot travel at the speed of light, we have to add one more ingredient: the energy associated with movement, so that the complete formula becomes ANDtwo=(mctwo)two+(pc)twowhere:

• AND: Energy.
• m: mass
• c: speed of light.
• p: momentum of the object, which is obtained by multiplying the mass of the object by its speed (p=mv).

In other words, the total energy of an object is the sum of its rest energy (mctwo)two and its energy associated with motion (pc)two. We already know that energy is equivalent to mass, so an increase in the speed of movement will increase the value of “p”, ergo of the energy in movement, ergo of the mass. Thus, as we accelerate more mass we have and more energy we need to keep accelerating. Hawking, in his book ‘Very Brief History of Time’, explains it as follows:

“At ten percent of the speed of light, the mass of an object is only 0.5 percent greater than at rest, while at ninety percent of the speed of light it would be more than twice the normal mass. Resting”.

That is, if we put an object at 90% of the speed of light, its rest mass will have more than doubled. Things get interesting as we get closer to those 300,000 kilometers per second, since the closer we get, the faster the mass increasesergo more energy is required to keep accelerating it, and so on.

The mass tends to infinity and, therefore, the energy needed to continue accelerating also

In other words, the mass tends to infinity and In order to reach the speed of light, infinite energy would have to be applied., something that, plain and simple, is not possible. To quote Hawking again, “any normal object is doomed to move forever at speeds less than the speed of light.” And why does light move at the speed of light? Does this phenomenon affect you? Because light is made up of photons, which are a very particular particle, forgive the redundancy. Not only do they have no mass, but they also don’t need to accelerate since they are at maximum speed from the moment they are created, that is, since their birth they are at 299,792.458 kilometers per second.

According to Hawking, “only light, or other waves that don’t have intrinsic mass, can move at the speed of light,” so unfortunately it’s not going to be possible to get from Tatooine to Coruscant in a couple of seconds, let alone Taking into account that distances in space are absurdly high. So much so that light, traveling at its enormous speed, takes 5:28 hours to reach Pluto’s surface from the Sun.

If something has taught us ‘Star Wars‘ the thing is Going at the speed of light is not easy. Han…

If something has taught us ‘Star Wars‘ the thing is Going at the speed of light is not easy. Han…