The universe may not expand forever! Scientist on new discovery: ‘This will shake up physics’

The mystery of dark energy

It has long been thought that the expansion of the universe, which began with the Big Bang about 13.8 billion years ago, should gradually slow down due to the action of gravity. However, in 1998, evidence of the existence of dark energy, the force that accelerates the expansion of the universe, was discovered. Studies of extremely bright star explosions, known as supernovae, have shown that distant galaxies are not slowing down, but rather; are actually moving away from each other faster and faster.

This discovery led to various theories about the future. Some have suggested that such an ever-accelerating universe might first spread out the stars so much that we would see almost nothing in the night sky, and then, in an even more shocking scenario, eventually tear the atoms themselves apart in what is called the “Great Rift.” However, there was also an alternative theory, that of the “Big Bang”, according to which the expansion would stop at one point and be reversed under the influence of gravity.

That idea seemed to have been discarded, but the latest results are bringing it back into play.

Revolutionary research that changes everything

In November, the Royal Astronomical Society (RAS) published research by a South Korean team that seems to confirm that dark energy is even more mysterious than we thought. Professor Young Wook Lee of Yonsei University in Seoul and his team reanalyzed data on supernovae, the same ones that first discovered dark energy 27 years ago.

However, instead of treating all explosions as having the same standard luminosity, they adjusted the data by taking into account the age of the galaxies from which they originated to calculate the actual supernova luminosity.

This adjustment showed not only that dark energy has changed over time, butć and, most shockingly, that the acceleration of the expansion of the universe is slowing down.

​- The fate of the universe will change – Professor Lee told the BBC.

​- If dark energy is not constant and weakens, it will change the entire paradigm of modern cosmology – he added.

The possibility of “Great Compassion”

If Professor Lee’s results suggest that the force pushing galaxies, dark energy, is weakening, then there is a possibility that it will become so weak that gravity will once again take over and start pulling galaxies back.

​- Instead of ending up with Big Ripping, Big Collapse is now a possible option. Which outcome will prevail depends on the true nature of dark energy, which we still do not know the answer to – says Professor Lee.

Divided reactions in the scientific community

Professor Lee’s work has been peer-reviewed and published in the prestigious Journal of the Royal Astronomical Society. Despiteč therefore, his claims were not well received by many leading astronomers, such as Professor George Efstathiou from the Institute of Astronomy at the University of Cambridge.

​- I think this just reflects the messy details of the supernova. The correlation with age is not very strong, so I think it is dangerous to apply such a ‘correction’. It seems weak to me – said Efstathiou.

The prevailing opinion is still that the universe is accelerating with almost constant dark energy.

However, Professor Lee firmly rejects such criticism.

​- Our data is based on 300 galaxies. The statistical significance is approximately one in a billion that it is a coincidence. That’s why I firmly believe that our research is more important. now very, very significant – said Lee.

Although the debate is far from over, these discoveries have brought unrest to the foundations of physics.

Professor Ofer Lehav of University College London, who is involved in another major dark energy study project, Desi, says that data on changing dark energy requires a completely new approach.

​- Now, with this dark energy rising and falling, we need a new mechanism. And that could shake the whole of physics – concludes Lehav.