When I first started learning about GR, I understood that a vacuum solution is one where the Einstein tensor vanishes, for the simple reason that the stress-energy tensor, T, vanishes. I have since read many times that the Ricci tensor vanishes for a vacuum solution. I am confused because to me this means that the scalar curvature is zero, and if there is no curvature, surely the space is flat?(adsbygoogle = window.adsbygoogle || []).push({});

I would appreciate it if someone could put me straight on this simple (I hope) misunderstanding.

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# Confused about curvature of vacuum solutions

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