The Evidence for Modern Physics

Forming the Milky Way and Other Galaxies (1x13)

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Until 100 years ago, our Milky Way galaxy was thought to comprise the entire universe. Now we think there are roughly a trillion galaxies of various sizes and shapes in the observable universe. Investigate how astronomers reached this conclusion and how they mapped the structure and contents of the Milky Way, discovering a supermassive black hole at its center—among other galactic attractions.