COSMOLOGICAL inflation is the idea that, in its first moments, the universe underwent a sudden, extreme expansion. This theory is widely accepted because it explains why space-time is almost perfectly flat and why matter in the cosmos appears so smoothly distributed on the largest scales. However, there are many versions of inflation, most of which would not lead to the universe as we observe it. The need for fine-tuning the theory to match observations makes some physicists uneasy.
Neil Turok, former director of the Perimeter Institute for Theoretical Physics in Waterloo, Canada, and now at the University of Edinburgh, UK, is among those who question inflation. Turok and Latham Boyle at the Perimeter Institute propose an alternative to inflation that can explain the evolution of the early universe without the need for fine-tuning. In 2018, they put forth a hypothesis based on one of the deepest symmetries of nature: a mirror universe that stretches backwards in time from the big bang.
Initially, the idea of an unobservable mirror universe was met with skepticism. The potential evidence from the observations of strange particles by the ANITA telescope in Antarctica, which were initially thought to support the hypothesis, turned out to be a false alarm. However, Turok and Boyle have further developed their thinking and now argue that the mirror universe can explain not only what inflation can, but also several other mysteries, including those of dark matter and dark energy. They have even made testable predictions in an effort to convince skeptics.
In an interview with Thomas Lewton, Neil Turok explains the concept of inflation and how it became widely accepted in the scientific community.
Overall, Turok’s argument for a reversed-time parallel universe offers an alternative to inflation theory and seeks to explain various cosmic mysteries. While initially met with skepticism, Turok and Boyle have made significant progress in developing their hypothesis and provide testable predictions to support their claims.
