Hubble Turns 36 — and Astronomers Still Can't Agree on How Fast the Universe Is Expanding

Thirty-six years ago today, NASA astronauts lifted a 12-ton mirror into orbit aboard the space shuttle Discovery. The Hubble Space Telescope — named for Edwin Hubble, who in 1929 had proved the universe was expanding — was supposed to give astronomers their first clear view of the cosmos, unfiltered by Earth's…