“Try to relax” is a paradox with a precise psychological mechanism. So is the traversable wormhole: the geometry you need to cross spacetime closes the moment you try to use it. The grandfather paradox, Wegner’s ironic monitoring process, and Rick Sanchez’s nihilism problem all share the same deep structure — and understanding that structure is more interesting than any of the individual cases.
LIGO uses 4-kilometre laser arms to detect gravitational waves at hundreds of hertz. Pulsar timing arrays use millisecond pulsars scattered across the Milky Way — arms measured in light-years — to detect gravitational waves at nanohertz frequencies, ten orders of magnitude lower. In June 2023, five independent pulsar timing arrays simultaneously announced the detection of a stochastic gravitational wave background. The Milky Way itself was the detector.
The EHT images of M87* and Sgr A* are remarkable not because they surprised us, but because they confirmed a century-old prediction at microarcsecond precision. The more interesting question: what would a wormhole look like? Completely different — and we have never seen that.