Vision is the dominant sense for (nearly all) human beings. So in a sense, we're all intimately familiar with light.

And yet light remains a mystery in many ways. Light acts like a wave, and like a particle (photon); quantum physicists have not yet explained how this dual nature of light is possible. We know light well with our bodies, but we don't really know it with our logic at all. (This alone could be fodder for a contemplative meditation practice.)

Light enters the eye through the pupil, and hits the retina at the back of the eye. There, photoreceptor (light-sensing) cells absorb the light. This is why your pupil looks black; all the light that enters is absorbed. (Unless there's too much light, as in a camera flash, in which case some of the light gets reflected back out and you have "red-eye.")

Think about that. Light was formed in the furnace of a star. For millions of years, it traveled through absolute emptiness at unimaginable speeds. Then it came upon you, gazing up at the night sky. The light entered your pupil, and you absorbed it into yourself. You now contain a tiny part of the energy of a star.

Or as Lorin Roche put it in his poetic Radiance Sutras:

Light moves on its pathways through space,

Enters the eyes, and

You absorb the luminous.

It's true, in a literal sense.

Enjoy your stargazing.