We may have been wrong about wormholes.
Recent research challenges the popular notion that wormholes—hypothetical tunnels through spacetime enabling interstellar travel—are directly linked to the original Einstein-Rosen bridge. In 1935, Albert Einstein and Nathan Rosen introduced a mathematical "bridge" connecting two symmetrically mirrored sheets of spacetime as a way to reconcile general relativity with quantum principles for describing particles in extreme gravitational fields. This structure was never intended as a traversable passage but served to maintain theoretical consistency.
Later interpretations repurposed the Einstein-Rosen bridge as the foundation for wormholes, envisioning them as shortcuts across space or even between universes.
However, emerging analyses argue this association represents a misunderstanding. Instead, the bridge is better understood in a quantum context as a connection involving time rather than spatial traversal: it links two microscopic arrows of time—one flowing forward and the other backward—in a mirrored, symmetric manner. At quantum-gravity scales, this time-reversal symmetry may be essential for the laws of physics to remain coherent.
This reinterpretation has profound implications for longstanding puzzles. For the black hole information paradox—where Stephen Hawking demonstrated in 1974 that evaporating black holes appear to destroy information, violating quantum mechanics' principle of unitarity—the mirrored time framework offers a resolution. Information falling into a black hole is not lost; it continues to evolve along the reversed time direction across the bridge-like structure, preserving unitarity without erasure.
The concept also reframes cosmology. The Big Bang might not mark an absolute origin but a quantum "bounce," where a contracting universe reverses its temporal direction, birthing our expanding cosmos. Some black holes could even preserve relics from a prior phase of the universe.
Ultimately, while practical wormhole travel across galaxies remains unlikely (or impossible) due to the instability and non-traversable nature of classical Einstein-Rosen bridges, this revised perspective could fundamentally reshape our understanding of time, black holes, information preservation, and the universe's origins.
[Enrique Gaztañaga et al, A new understanding of Einstein–Rosen bridges, Classical and Quantum Gravity (2026). DOI: 10.1088/1361-6382/ae3044]
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