In general relativity, non-negativity of this quantity is formulated by namesake “conditions.” For 10 points each:
[10e] Name this quantity, which equals mass times speed of light squared.
ANSWER: energy [accept energy conditions]
[10h] By the positive energy theorem, a spacetime with this property satisfying the dominant energy condition must have positive ADM mass. Spherically symmetric solutions to the Einstein field equations are static and have this property, by Birkhoff’s theorem.
ANSWER: asymptotic flatness [or asymptotically flat; accept answers referring to being flat or having zero curvature in the asymptotic limit; prompt on flatness or zero curvature]
[10m] Birkhoff’s theorem therefore specifies the uniqueness of this solution to the Einstein field equations. This solution describes the spacetime around a spherical mass with zero angular momentum and charge.
ANSWER: Schwarzschild metric [or Schwarzschild solution]
<GC, Physics>