Recap: dark matter and galaxy rotation
In the late 1970s, astronomers Vera Rubin and Kent Ford of the Carnegie Institution observed our most well-known galactic neighbor: the Andromeda galaxy. And when they did, they discovered that the galaxy wasn't rotating the way they expected. In our solar system, the planets rotate around the Sun at different rates. Close-in Mercury moves much quicker than distant Neptune. However, in Andromeda, the visible stuff on the galaxy's outer rim moves just as fast as the stuff orbiting near the galaxy's core.
Rubin and Ford were perplexed. It meant the Andromeda galaxy must be saturated with huge amounts of invisible matter, stretching far from the galaxy's center. Ultimately, their discovery turned out to be the first direct evidence for dar
Astronomers find 19 more galaxies missing their dark matter
In the late 1970s, astronomers Vera Rubin and Kent Ford of the Carnegie Institution observed our most well-known galactic neighbor: the Andromeda galaxy. And when they did, they discovered that the galaxy wasn't rotating the way they expected. In our solar system, the planets rotate around the Sun at different rates. Close-in Mercury moves much quicker than distant Neptune. However, in Andromeda, the visible stuff on the galaxy's outer rim moves just as fast as the stuff orbiting near the galaxy's core.
Rubin and Ford were perplexed. It meant the Andromeda galaxy must be saturated with huge amounts of invisible matter, stretching far from the galaxy's center. Ultimately, their discovery turned out to be the first direct evidence for dar
Astronomers find 19 more galaxies missing their dark matter










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