📖 what
What is a galaxy rotation curve?
AstronomyDark Matter Evidence
Quick Answer
A galaxy rotation curve is a plot of how orbital speed changes with distance from a galaxy’s center. Unexpected flat rotation curves are one of the key clues for dark matter.
The Full Story
In a simple model, stars farther from a galaxy’s center should orbit more slowly, much like planets farther from the Sun. But observations, notably those expanded by Vera Rubin’s work in the 1970s, showed that many spiral galaxies have flat rotation curves: outer stars move faster than expected. This suggests there is much more mass than we can see. Rotation curves are a major piece of evidence for dark matter in galaxies.
Key Facts
1.Flat rotation curves imply extra unseen mass
2.Vera Rubin’s work was influential in the 1970s
3.They are important evidence for dark matter
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Suggested video title for this topic:
"The galaxy clue that pointed scientists toward invisible matter"