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RetroScience: Astronomer Edwin Hubble Discovers Galaxies Beyond The Milky Way

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Want to travel back in time? In our weekly “Retro Science” series, we’re digging up visual artifacts that capture fascinating moments from science history, including surprising studies, outdated inventions, and breakthrough achievements. By recapturing science’s impressive feats and most amusing flops, RetroScience will remind us of how far we’ve come, and how far we have yet to go.

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1937: Astronomer Edwin Powell Hubble stargazes through the Hooker telescope at California’s Mount Wilson Observatory.

In 1922, American astronomer Edwin Powell Hubble looked through the eyepiece of the 100-inch Hooker telescope at California’s Mount Wilson Observatory. There, Hubble identified Cepheid variables, a type of star, in several spiral nebulae, including the Andromeda Nebula and Triangulum. Hubble concluded that these nebulae were too far away to be part of the Milky Way, suggesting the existence of entire galaxies outside our own. Many scholars opposed this theory at the time, defending the prevailing view that our universe consisted entirely of the Milky Way Galaxy. Despite the opposition, Hubble ended up publishing his research on nebulas, earning him awards from the American Association Prize and Burton E. Livingston of the Committee on Awards. His contributions opened up the field of extragalactic astronomy and revolutionized the way we see our universe.