25
votes
Accepted
How high does the ocean tide rise every 90 minutes due to the gravitational pull of the space station?
Bigger than an atomic nucleus but smaller than an atom.
The tidal forces scale as $MR^{-3}$, where $M$ is the mass of the object causing the tides and $R$ would be its separation from the centre of ...
- 158k
1
vote
How low would the mass of a sphere of uniform density 1 megaparsec in diameter need to be before the expansion of the universe could tear it apart?
To begin with some (perhaps semantical) clarification, expansion of the universe does not tear things apart. Cosmic expansion is not a force; it's just a description of the motion of the universe. In ...
- 4,777
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