Light travels at different speeds based on the medium it passes through. For example, in a vacuum, it travels at 3.0 × 10^8 m/s in a straight line. But when directed towards glass, air, diamond, water ...
Such great telescopes as the 200-incher on Mt. Palomar see only tiny patches of sky. They need a more wide-eyed instrument to tell them where to look. Last week CalTech and the National Geographic ...