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Galaxies quick check

A quick check of 3 questions. After you submit, each question shows the right answer and why.

3 of 8 questions, Advanced level. Aimed at the Advanced level, your current depth. Questions you have not answered yet come first.

Show all 8 questions

ScientistQuestion 1 of 3

What did Edwin Hubble use in 1923 to show that the Andromeda nebula lies outside the Milky Way?

ScientistQuestion 2 of 3

Stars far from a spiral galaxy's centre orbit faster than the visible matter can explain. What do astronomers conclude, and why?

AdvancedQuestion 3 of 3

For a star on a circular orbit, v² = GM(r)/r. If a galaxy's rotation speed v stays roughly constant at large r, how must the enclosed mass M(r) behave, and what does that imply?