The theory the universe has been expanding at an increasing rate, first proposed in the late 1990s, is now facing a new round of criticism by a team of physicists at Oxford University.

The scientists, led by Professor Subir Sarkar, a fellow at the Neils Bohr Institute, is challenging the Nobel-winning idea that dark energy is driving accelerated expansion. After analyzing a catalog of 740 Type Ia supernovae, ten times more than the original 1990s sample size, the researchers said the accelerated expansion theory falls short of scientific accuracy, according to the study published in Scientific Reports.