As NASA's Curiosity rover continues to beam back unprecedented images of the Martian landscape, we are reminded of the countless celestial discoveries made by the space agency's longest-running mission: the Hubble Telescope.

The Hubble has been whipping around Earth at a speed of five miles per second since its launch in 1990.

During its 22-year run, the school-bus-sized telescope has sent hundreds of thousands of images back to Earth that have given scientists a glimpse of the most distance stars and galaxies and helped to determine the age of the universe.

The telescope has changed our understanding of the universe forever.