Space & Astronomy

Expansion of the universe 'may be constant'

By T.K. Randall
October 22, 2016

Image Credit: (PD) NASA/ESA/ESO/Wolfram Freudling et al via Wikimedia Commons Back in the 1990s, three astronomers made a fundamental discovery about the expansion of the universe that would go on to not only win them a Nobel Prize, but would also cement the idea that the expansion of the universe is accelerating - a process driven by the mysterious 'dark energy'.

Now however a team of scientists headed up by Professor Subir Sarkar of Oxford University's Department of Physics have cast doubt on this idea by analyzing a much wider set of data.

The original research involved analyzing Type Ia supernovae to determine the amount by which the universe had expanded within a given time frame. The new study, by contrast, was able to draw on a catalogue of supernovae more than ten times the size.

The results seemed to suggest that the evidence for an accelerating expansion was a lot flimsier than previously thought and that the data was consistent with a constant rate of expansion."The discovery of the accelerating expansion of the universe won the Nobel Prize, the Gruber Cosmology Prize, and the Breakthrough Prize in Fundamental Physics," said Professor Sarkar.

"It led to the widespread acceptance of the idea that the universe is dominated by "dark energy" that behaves like a cosmological constant -- this is now the "standard model" of cosmology."

"However, there now exists a much bigger database of supernovae on which to perform rigorous and detailed statistical analyses. We analysed the latest catalogue of 740 Type Ia supernovae -- over ten times bigger than the original samples on which the discovery claim was based."

"We found that the evidence for accelerated expansion is, at most, what physicists call '3 sigma.' This is far short of the '5 sigma' standard required to claim a discovery of fundamental significance."

Source: Science Daily

Tags: Universe, Expansion