In April 1990, a tin can the size of a school bus was dropped off 353 miles above the Earth’s surface. Its mission: Take clear pictures of the universe without interference from the planet’s atmosphere. Nineteen years later, NASA’s Hubble Space Telescope has transmitted hundreds of thousands of spectacular images to astronomers back home. From far-away stars and neighboring planets to evidence of dark matter and the precise age of the universe, these photographs have allowed us to see what once existed only in scientists' computations.