If you recall anything from your GCSE Physics, you may recall that there are some absolute physical constants in our universe which set the limits that define our existence. These include the masses of subatomic particles, the gravitational constant, and the speed of light. A photon of light travels at a speed of 299,792,458 km/s. It is the maximum speed that any object can travel at. Albert Einstein’s famous equation for converting mass to energy relies on this value, c, to determine the energy released.
In astronomy, we quantify distances using light as a measure based on how far it’s travelled, which is where time comes into play. Since distance covered is speed multiplied by time, astronomers use light second, light-minute, light-hour, light-year, and more to create a scale to…