Space is… big. Any story that involves characters traversing it needs to come up with a way to address the vast distances between galaxies.
There are a few ways that sci-fi writers get around this problem of moving their protagonists from one point in space to another, including teleportation, wormholes and faster-than-light travel.
Travelling at the speed of light – around 300,000km (186,000 miles) per second – would allow you to circumnavigate Earth 7.5 times in a single second and get you to the surface of the Sun in a little over 8 minutes.
But if you wanted to visit Earth’s nearest neighbouring star system, Alpha Centauri, some 40,000 billion kilometres away, your journey would take just under 4 years and 3 months.
If faster-than-light travel was an option, though, you could explore the whole Universe.
Unfortunately, not only is it impossible for anything to go faster than the speed of light, but according to Einstein’s special theory of relativity only things with zero mass at rest (like photons) can travel at the speed of light.
Things with mass, like us and spaceships, will always have to travel at subluminal speeds.
Faster-than-light in science fiction
There are ways in which science-fiction writers have attempted to explain away faster-than-light travel, however.
The 1997 movie Event Horizon explores the idea that a spacecraft might effectively travel faster than light by folding the fabric of space on itself, thereby creating a means of travelling across the Universe in an instant.
Interestingly, it’s possible that the speed of light hasn’t always been constant.
Observations suggest that there were different wavelengths of light billions of years ago.
Some have even postulated that this could support the notion of extra space dimensions where the laws of physics are different.
Maybe, then, we could one day enter the hyperspace dimension to visit a galaxy far, far away…
