Researchers suggesting that the speed of light varies have come up with a numerical prediction that will allow their theory to be tested.

Many theories in physics are built upon the idea that the speed of light is at a constant rate, but João Magueijo and Niayesh Afshordi think otherwise. In a paper published in the journal Physical Review D, they detailed the creation of an exact figure on the spectral index, a model that can be used to determine if their theory is valid or not.

All structures in the universe today were created when fluctuations occurred in the early universe. The spectral index is the record of these fluctuations that is now integrated into the cosmic microwave background.

The figure that Magueijo and Afshordi came up with is 0.96478 precise, which is extremely close to the currently used estimated readings of 0.968, give or take some margin for error, gathered from the cosmic microwave background.

A Radical Physics Idea

Magueijo and Afshordi's theory that the speed of light is variable was first proposed back in the late ‘90s. It was considered as radical at the time but now that a numerical method of prediction has been developed, the theory has turned into something that physicists can validate for themselves.

"The theory ... has now reached a maturity point... If true, it would mean that the laws of nature were not always the same as they are today," said Magueijo.

Theories On The Speed Of Light

If light speed varies, it would suggest that there was a much higher speed of light during the time of the early universe, which allowed faraway edges to connect as expansion ensued. And as the universe's density changed then, the speed of light would have also dropped in a manner that was predictable.

The more mainstream theory on the speed of light is inflation, which tries to solve the horizon problem by stating that the early universe had evened out in its infancy and then expanded suddenly. However, the universe stayed uniform throughout this expansion. If the inflation theory is true, it would preserve Albert Einstein's theory that light speed is constant, as well as other physics laws known today. However, for it to be proven true, an inflation field will have to be invented. An inflation field is a set of conditions that existed only at the time.

The inflation theory also points to a universal expansion rate much faster than what the current universe is experiencing.