New answers tagged distance
The amplitude of quadrupole radiation is proportional to the source's value of $d^3 x/dt^3$. This applies to both electromagnetic radiation and gravitational radiation (for which quadrupole radiation is the lowest possible multipolarity).
As far as we can tell (up to energy scales we've measured so far), spacetime is a nice and smooth manifold. It might happen that the smoothness is approximate and spacetime is discrete at a much more microscopic scale, or it could turn out that spacetime is smooth all the way through. Short answer: We don't know. About the notion of energy quantization: ...
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