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m/ Support Space Time on Patreon https://www.patreon.com/pbsspacetime The search for a single number: the hubble constant, which is the rate of expansion of our universe, has consumed astronomers for generations. Finally, two powerful and independent methods have refined its measurement to unprecedented precision. The only problem is that they don’t agree. This calls into question some of our most basic assumptions about the universe. Tweet at us! @pbsspacetime Facebook: facebook.com/pbsspacetime Email us! pbsspacetime [at] gmail [dot] com Comment on Reddit: http://www.reddit.com/r/pbsspacetime Help translate our videos! https://www.youtube.com/timedtext_cs Previous Episode: Why String Theory Is Wrong https://youtu.be/IhpGdumLRqs Hosted by Matt O'Dowd Written by Matt O'Dowd Graphics by Luke Maroldi Directing by Andrew Kornhaber In 1929, Edwin Hubble discovered the universe. He gave us our first incontrovertible proof that there are galaxies outside the Milky Way by measuring the distances to the spiral nebulae. They were many millions of light years from us –far outside the Milky Way and so must be galaxies in their own right. Combined with the Doppler-shift velocity measurements of Vesto Slipher, Hubble revealed that the galaxies are not only receding from us, but they are receding at a rate proportional to their distance. Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters: Big Bang Anton Lifshits CoolAsCats David Nicklas Fabrice Eap Juan Benet Justin Lloyd TIm Davis Quasar Dean Fuqua James Flowers Mark Rosenthal Tambe Barsbay Vinnie Falco Hypernova Chuck Zegar Danton Spivey Donal Botkin Edmund Fokschaner Jens Theisen John Hofmann Jordan Young Joseph Salomone Mark Heising Matthew O’Connor Thanks to our Patreon Gamma Ray Burst Supporters: Alexey Eromenko Antonio Ruiz Bradley Jenkins Brandon Labonte Buruk Aregawi Carlo Mogavero Daniel Lyons David Behtala David Crane David Schmidt Dustan Jones Geoffrey Short Greg Weiss Jack Frosch James Hughes James Quintero Jinal Doshi JJ Bagnell John Webber Jon Folks Jonah Joseph Emison Josh Thomas Kenneth F Leonard Kevin Warne Kyle Hofer Malte Ubl Mark Vasile Nathan Hitchings Nicholas Rose Nick Virtue Richard Broman Sammy J Scott Gossett Sigurd Ruud Frivik Tommy Mogensen سلطان الخليفي