Revise GCSE Physics


Question:Does the fact that the speed of light is not infinite cause any problems?

Although the speed of light is very fast, it is not infinite. This means that it takes time for light to travel from one place to another. Usually we do not notice this because the speed of light is very fast and the distance we usually deal with are quite small.

However when looking out into the huge distances of outer space the time taken by light to travel becomes noticeable and even cause practical problems.

Radio signals also travel at the speed of light. This means that they take a long time to travel through the Solar System.

For example, it takes just over one second for a signal to reach the Moon from the Earth, and up to 21 minutes to reach Mars. So having a conversation between the Earth and a spacecraft becomes increasing difficult with distance and might even cause problems if an astronaut was trying to ask for emergency information.