A wormhole is a hypothetical tunnel in curved spacetime connecting two distant regions of the universe and potentially shortening the journey between them. In Einstein's classical theory (general relativity), such a tunnel, known as an Einstein–Rosen bridge, is extremely unstable: it collapses almost immediately after formation. To keep it open, you would need a "prop" — exotic matter with negative energy density, producing an antigravity effect. Since no such substance has ever been detected experimentally, wormholes have long been considered a purely mathematical abstraction.

In a recent theoretical study, scientists revisited the very laws of gravity by modifying the field equations. In their model, rotation plays the key role: like a centrifugal force, it pushes the tunnel walls apart and prevents collapse. The whirlpool analogy captures the essence: a swirling fluid creates a stable vortex that doesn't collapse as long as the rotation persists. The authors' calculations show that maintaining such a rotating wormhole requires no exotic forms of matter — just ordinary matter with positive energy density. The rotation drags the surrounding spacetime along with it (the frame-dragging effect), causing light rays to loop around the throat.

The most surprising consequence of the model is the possibility of the wormhole functioning as a time machine. Spacetime around it twists so strongly that closed timelike curves form: a hypothetical traveler who dives into one end could emerge from the other before the moment of entry. To a distant Earth observer, such an object would cast a characteristic double shadow with a bright ring — a signature distinct from the shadows of black holes or neutron stars. The authors suggest that future telescopes, with sufficient resolution, could detect this specific optical trace and thereby confirm or rule out the existence of rotating wormholes.