Anaxagoras was born to a wealthy family, but gave up his wealth to become a scientist. He was the first Ionian to go to Athens, bringing the new Ionian philosophical tradition to the Greek homeland. He becomes friends with Pericles.
Anaxagoras taught that the sun was a hot rock, and that the moon shone from the reflected light of the sun. He also understands that eclipses are caused when the moon passed through the shadow of the earth (a lunar eclipse) or when the moon gets in between the sun and the moon (a solar eclipse.) He ends up in jail in Athens for teaching that the sun and moon were not gods, but merely places. Pericles gets him out of jail eventually.
Anaxagoras does not believe in a divine intelligence that runs the universe. While he does believe that there is some sort of life force that causes the universe, and all in it, to run, this life force isn't by definition an intelligent thing. (Kind of like The Force in Star Wars.)
There is a great quote attributed to Anaxagoras. He was asked what was the purpose in being born. He replied "The investigation of sun, moon, and heaven."