Not really worthy of a top comment, but I figured I would throw something in here. Much of modern optics and astronomy is from Islamic sources.

A man named Avicenna has a quote from ~1000 "observed that if the perception of light is due to the emission of some sort of particles by a luminous source, the speed of light must be finite."

Abū Rayhān al-Bīrūnī discovered that the speed of light was much faster than the speed of sound shortly after.

Pretty important stuff for the time period. They also managed to explain the origin of rainbows (who doesn't like rainbows?) in the 1400s.

They also did quite a bit of experimenting with lenses and parallax, picking up after the greeks. Eventually their work lead to Europe to create the first working telescopes.