Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly it’s expanding also allows us to run the clock backward 14 billion years to the way the universe began – with a bang.
Chapters:
Introduction: The Origins of the Universe 00:00
Distant Galaxies Show a Redshift in Their Spectra 2:07
The Universe is Expanding 4:13
The Big Bang 5:12
Lookback Time 6:06
The Cosmic Microwave Background 7:50
What is the Universe Expanding Into? 9:17
Review 12:12