Overview
- A paper by UC Davis mathematicians, which was published 27 May 2026, presents a mathematical stability analysis that concludes Friedmann spacetimes are unstable at the Big Bang.
- The authors say that this instability means the standard Lambda‑cold dark matter (ΛCDM) model cannot be a stable solution of the Einstein equations with or without dark energy.
- Using a self‑similar form of the Einstein‑Euler equations the team identifies a family of solutions in the radiation epoch that behave like an expanding wave or shock and can produce temporary accelerated expansion.
- The result is a theoretical, peer‑reviewed mathematical claim and not an observational detection; the paper is limited to specific classes of solutions and its match to supernova, cosmic microwave background, and other data remains untested.
- If the mechanism holds up, it would force rethinking of assumptions such as the Copernican principle and prompt targeted observational tests and follow‑up analyses to look for the model's distinct signatures in astronomical surveys.