What key finding did Vera Rubin and Kent Ford discover when comparing measured rotation speeds to Keplerian predictions?
Answer
Orbital speeds remained surprisingly high and nearly constant, or flat, far out.
Instead of the expected decline, they found that the orbital speeds remained constant, or flat, even at radii extending far beyond where most of the luminous matter resides.
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Astrophysics: Galaxy Rotation Curves and Dark Matter - YouTube
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