But according to relativity, their possible existence can’t be ruled out. There are, however, hypothetical particles called tachyons with a special kind of mass called “imaginary mass”. This universal speed limit applies to anything with what we might call “ordinary mass”. Since you and I have mass, don’t expect to be travelling at twice the speed of light anytime soon. That would mean there isn’t enough energy in the Universe to accelerate something with mass up to the speed of light. Indeed, it’s plausible the Universe only contains a finite amount of energy. The equations of relativity tell us that anything with mass – regardless of how much mass it has – would require an infinite amount of energy to be accelerated to the speed of light.īut all of the sources of energy we know of are finite: they are limited in some respect. The faster we want the object to go, the more energy we’ll need. To accelerate an object with mass, we have to add energy. Specifically, relativity tells us that nothing with mass can accelerate past the speed of light. According to this theory, the speed of light operates as a universal speed limit on anything with mass. One of our best physical theories at the moment is the theory of relativity, developed by Albert Einstein. However, for certain strange particles, travelling at twice the speed of light might be possible – and it might send those particles back in time. In fact, it’s not possible for any object with the kind of mass you or I have to move faster than the speed of light. As far as we know, it’s not possible for a person to move at twice the speed of light.

Everything moves at the speed of light