Gravitational memory makes wormholes more stable ⚡ экспресс
Wormholes supported by the Casimir effect (negative pressure between plates) are investigated with a correction for gravitational memory — a residual disturbance of the vacuum after a gravitational wave. Just like a rubber sheet remembers the shape of an object, the vacuum retains an imprint, adding positive energy to the usual Casimir repulsion. The throat shape and allowed parameters are obtained; solutions can match the shadow of the black hole M87*. This relaxes the requirements for exotic matter, bringing wormholes closer to reality.
Wormholes — tunnels through curved spacetime, allowed by general relativity. To be stable, they need repulsive energy — the kind that pushes apart rather than attracts. A source can be the Casimir effect, discovered by Hendrik Casimir: two plates in a vacuum are drawn together as if the space between them pushes them outward.
A gravitational wave passing through a wormhole leaves behind a strain — gravitational memory: a trace that doesn't fade away. Inside the tunnel, this trace adds ordinary energy to the repulsive kind, blending them. Near the throat, the repulsion is stronger, while along the sides the tunnel is held more gently — the wormhole becomes stable.
Recalculating the shape, the authors showed: such a wormhole casts a shadow like a black hole, precisely matching the silhouette of M87* measured by the Event Horizon Telescope. A surprise: if several waves have passed, the imprints stack up, and the shadow may quiver. Perhaps telescopes are already seeing these objects, not yet distinguishing them from black holes.
🎯 The Casimir effect was predicted by Hendrik Casimir in 1948 over a cup of coffee while discussing the properties of the vacuum.
🎬 The wormhole as a portal is familiar from the movie Interstellar, where the scientific basis was laid by [scientist:Kip Thorne]Kip Thorne[/scientist].