# Does spacetime have momentum?

In what sense can it be said that spacetime possesses momentum? Can an experiment be envisaged to test this question?

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From the perspective of classical general relativity at least, spacetime is really more like a container for objects that can possess energy or momentum. Einstein's equations $$G_{\mu\nu} + g_{\mu\nu}\Lambda = 8\pi T_{\mu\nu}$$ then basically tell you how such objects curve spacetime. The left hand side of this equation contains quantities that determine what spacetime looks like, and the right hand side represents the energy and momentum of all the stuff you put in it. So the answer from the perspective of classical general relativity is no, spacetime does not possess momentum, but it is affected by things that do.