Light as energy Light is remarkable. It is something we take for granted every day, but it's not something we stop and think about very often or even try and define. Let's take a few minutes and try and understand some things about light. Simply stated, light is nature's way of transferring energy through space.
Light travels very rapidly, but it does have a finite velocity.
However, when we start talking about the incredible distances in astronomy, the finite nature of light's velocity becomes readily apparent. It takes about two and a half seconds, for instance, for a radio communication travelling at the speed of light to get to the moon and back. Sunrise from the Space Shuttle, STS-47 mission. We should also highlight right up front that light is more generally referred to as electromagnetic radiation . Okay, we used a big word.