In photolithography, we take electromagnetic radiation, or what we tend to call light, and we use it to shrink down some of that circuitry, so that we could cram more of it into a really small space.
And just consider this: that no matter where we look, in any direction, we see electromagnetic radiation dating from the earliest days of the universe, traveling everywhere as the universe itself expands.
Since it does not emit or absorb electromagnetic radiation, it cannot be detected or observed directly, in contrast to other celestial bodies in the universe.