Can light exist without darkness?

To the great dismay of the great existentialist thinkers, scientifically speaking, this is not that difficult a question to tackle.

From a physics perspective, “light” is just a series of particles zooming through space, a little beam of radiation heading outwards in the cosmos. An individual particle of light usually doesn’t care whether it’s surrounded by lots of other photons, or whether it is off on its own in the universe, travelling a unique path.

Darkness is usually described simply as the absence of light; this description also works pretty well as a physical description. By this standard, “light” and “darkness” are just a binary toggle between “radiation” or “not radiation”.

The question here is asking if you can have only radiation - only light - and skip the “no radiation” part entirely. If you remove darkness, could you still have light? If you’re thinking about darkness and light in terms of a yes/no toggle, then this is perfectly possible. You just hold the toggle at “yes” at all times. The individual light particles won’t care that they’re not letting “not radiation” not have its times - they’re simply travelling forwards.

The ways that our universe produces light are also independent on a lack of light nearby. Stars form light as a byproduct of the incredible pressures at their centers, and are most often formed in clusters - with tens to hundreds of other stars forming nearby. New stars only unveil themselves to our eyes by using the light they give off to burn away the dust and gas that hid them in darkness.

There are two major reasons for darkness in the universe. The first is to be in shadow. The physical blocking of light by an object is an easy way to be in darkness. That’s all night is on Earth, after all - you’re in the shadow of the planet. The second is that the universe hasn’t existed for an infinite amount of time. If the universe had already existed for an infinite amount of time, our skies would be brilliant with light both day and night, as the light from every star in the universe streamed towards us, brightening our skies. In that case, the only sources of darkness would be the shadows.

In that universe, perhaps we would be asking the question the other way around - is there any darkness without the light?

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