Universe growth could also be slowing, not accelerating, examine suggests | Astronomy

Astronomers have forged doubt on a Nobel prize-winning principle that the growth of the universe is accelerating, suggesting that as a substitute it might be slowing down.

If confirmed, this is able to have profound implications for the destiny of the universe, elevating the chance that reasonably than increasing for ever, the universe may in the end enter a reverse massive bang state of affairs referred to as the massive crunch. The astronomers behind the work say their observations additionally indicate that darkish power – the mysterious drive regarded as propelling the growth of the universe – is weakening over time.

“Our study shows that the universe has already entered a phase of decelerated expansion at the present epoch and that dark energy evolves with time much more rapidly than previously thought,” stated Prof Young-Wook Lee, of Yonsei University in South Korea, who led the work. “If these results are confirmed, it would mark a major paradigm shift in cosmology since the discovery of dark energy 27 years ago.”

The paper is prone to be greeted with heavy scepticism, however with the influential Desi consortium independently reaching the same conclusion earlier this 12 months, a fierce debate is opening up in cosmology over the character of darkish power and the possible destiny of the universe.

The newest work focuses on the reliability of observations of distant supernovae (exploding stars) that led to the invention of darkish power, work that was awarded the 2011 Nobel prize in physics.

“It has been 27 years since the discovery of dark energy and the accelerating universe,” stated Lee. “There was a key assumption, however, which turned out to be incorrect. It’s like doing up a shirt with the first button fastened incorrectly.”

Until the Nineties, it was assumed that gravity would act as a cosmic brake, slowing down the growth of the universe by pulling galaxies again in the direction of one another.

This view was upended when astronomers made the primary estimates of the growth of the universe utilizing observations of exploding stars, referred to as kind 1a supernovae. These supernovae have been regarded as uniquely uniform within the gentle they emitted, which means they may function “standard candles”, whose brightness was a proxy for his or her distance. This allowed astronomers to measure how briskly completely different components of the universe have been receding by measuring the redshift (the stretching of sunshine because of the growth of the universe) of supernovae throughout the cosmos.

The observations revealed that distant supernovae have been dimmer than anticipated for a universe whose growth was slowing down. This led astronomers to conclude that the growth of the universe had sped up – and was nonetheless accelerating.

However, the newest findings supply another rationalization. By estimating the ages of 300 host galaxies utilizing a unique technique, the workforce concluded that there are merely variations within the properties of stars within the early universe that imply they produce, on common, fainter supernovae.

Correcting for this systematic bias nonetheless leads to an increasing universe, however means that the growth has slowed down and that darkish power is waning, the evaluation concluded. If darkish power retains lowering to the purpose the place it turns into unfavorable, the universe is theoretically predicted to finish in an enormous crunch.

Prof Carlos Frenk, a cosmologist on the University of Durham, who was not concerned within the newest work, stated the findings have been worthy of consideration. “It’s definitely interesting. It’s very provocative. It may well be wrong,” he stated. “It’s not something that you can dismiss. They’ve put out a paper with tantalising results with very profound conclusions.”

The findings are revealed in Monthly Notices of the Royal Astronomical Society.