Watch Trailer
DISCLAIMER: Not all titles shown are currently available on all streaming providers.

Watch Crash Course Astronomy Season 1 Episode 42 Online

  • 8/10
  • Subtitles: English

Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly its expanding also allows us to run the clock backwards 14 billion years to the way the universe began - with a bang.