Space itself is not inherently lit by light because light requires a source to be generated and propagate through a medium. While light is an electromagnetic wave, it needs a medium to interact with in order to be detected or observed.
In the case of space, which refers to the vast regions between celestial bodies, it is primarily a vacuum or near-vacuum devoid of significant matter or particles. In such a vacuum, there is no medium for light to interact with and propagate through.
Light travels in straight lines until it encounters an object or medium that can absorb, reflect, or scatter it. In the absence of objects or significant particles in space, there is nothing to interact with the light waves and cause them to scatter or be absorbed. Consequently, when we observe the vast empty regions of space, they appear dark because there is no source of light or medium to reflect and scatter light towards us.
However, it's important to note that space is not completely devoid of all forms of light. There are various sources of light in space, such as stars, galaxies, and other celestial objects that emit light. When we observe these objects, we can detect the light they emit, allowing us to see them. Additionally, there are also phenomena such as cosmic microwave background radiation that permeate space, providing a faint residual glow.
In summary, while space itself does not contain light in the sense of being uniformly lit, it does allow for the propagation of light waves emitted by celestial objects and other sources of electromagnetic radiation.