Running Rings Around Inflation

More people are getting tired of old cosmologies. The old inflationary paradigm proposed that the early Universe expanded at warp speed, many times faster than light. The distinguished Roger Penrose of Oxford has long been a critic of inflation. When others claimed that the Cosmic Microwave Background somehow "proves" inflation, Penrose wrote "In my opinion, we must be exceedingly cautious about claims of this kind--even if seemingly supported by high-quality experimental results. These are frequently analysed from the perspective of some fashionable theory." Penrose prefers to work on cyclic cosmologies, where the Universe recycles itself over billions of years.

In November Penrose and Vahe Gurzadyan claimed to have discovered ring formations in the CMB. They interpret these splashes in the cosmic pond as evidence of explosions in a previous Universe. Penrose sees the rings as supporting his cyclic cosmology. Other cosmologists claim that such rings are just the result of events in our own Universe. The controversy shows that not everyone believes in the mainstream cosmology.

More than 30 years after it was first proposed, the inflationary paradigm has not led to a compelling theory. Faster-than-light inflation would violate both the First Law of Thermodynamics (conservation of energy) and Relativity's stipulation that nothing travels faster than light. Inflation can never be proven--no human experiment can time-travel to the first 10^{-33} seconds to observe inflation in action, or even approach the titanic energies so near the Big Bang. The paradigm has created a cottage industry of competing theories, none of which can be proven soon. Physicist Paul Steinhardt, one of inflation's original architects, has abandoned the paradigm and now also works on cyclic cosmologies.

At one time NASA's Beyond Einstein program included an "inflation probe," an unspecified Space experiment to search for inflation's signature. Scientists could not agree what form such an experiment could take. After much argument, Beyond Einstein was concentrated on a Joint Dark Energy Mission, which itself has little chance of ever flying. Ambitious Space experiments involving inflation have led to naught.

In contrast, a cosmology where the speed of light was much faster can be tested today, for it also predicts that c continues to slow. As methods of measurement become more precise, such a surprising prediction can be tested. Experiments showing a c change would be the death knell for the inflationary paradigm. With their idea receding, inflation's proponents are ready to blow up.