What observations were used by Edwin Hubble to show that the universe is expanding?
- The distance to a galaxy is proportional to its luminosity.
- The distance to a galaxy is inversely proportional to its apparent size.
- The distance to a galaxy is proportional to its velocity relative to the Milky Way.
- The distance to a galaxy is proportional to its rotational velocity.
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The distance to a galaxy is proportional to its velocity relative to the Milky Way.
The fact that the distance to a galaxy is proportional to its velocity relative to the Milky Way indicated to Hubble that the universe is expanding.
1 answer