Schwazschild Wormholes

Einstein-Rosen bridges
close quickly, unless held by
exotic matter

On a side note, this phenomena was posthumously named after Karl Schwazschild, even though he had been dead almost 5 years before anyone even postulated about what are now known as wormholes; and almost 20 before Einstein and Rosen found a solution for them in the Einstein field equations. That’s a damn fine publicist, right there.