In 1905, Albert Einstein published his theory of special relativity. This stated that travel at the speed of light is impossible. He argued that the faster an object moves, the heavier it becomes, so that an object travelling at the speed of light would have infinite mass, which is impossible. Spacecraft are getting faster and faster but may never be able to reach the speeds needed to travel between stars.
If we ever want to travel to, ahem, galaxies far, far away, we’ll need to find a way of getting there within our lifetime. For example, travelling to Alpha Centauri, one of our closest galactic neighbours 4.35 light years away, would take approximately 70,000 years if we made the journey at the same speed as NASA’S Voyager 1 probe. Even Yoda would struggle with that time scale.
One way to push the boundaries of space exploration is to travel faster than light, which is a mindboggling, 670,616,629mph, or 1.07bn km/hr. By comparison, the fastest manmade spacecraft – NASA’S Juno Probe – briefly reached 165,000 mph (266,000 km/h).
But according to our understanding of the laws of physics, it’s impossible to break ‘c’, the cosmic speed limit set by Albert Einstein.
The main barrier that we – and most particles – have is mass. Any object with mass accelerates, gaining energy, but it always needs more to accelerate further. So, propelling us to the speed of light would take an infinite amount of energy. ‘There is simply no fuel source big enough to accelerate you or I to light speed,’ Peter William Millington, a research fellow at the University of Nottingham explained. But that hasn’t stopped scientists trying to find a workaround to this mammoth problem. Teams at the CERN laboratory in Switzerland tried to get neutrinos – the lightest known particles in the universe – to exceed the speed of light but failed.
However, their efforts were not without drama. In 2011, the OPERA (Oscillation Project with Emulsion tracking Apparatus) team made an announcement that promised to rewrite our understanding of the universe, by saying they had ‘high confidence’ that neutrinos had travelled faster than light, giving science fiction fans immediate hope that spacecraft might be possible. Theoretically, at least. However, it turned out that the results were wrong due to a faulty cable connection in the GPS system used to time the particles. This made their journey look around 73 nanoseconds speedier than it was. So for now, at least, we won’t be able to travel beyond the speed of light based on our current understanding of the laws of physics.