A new controversy is rocking the international scientific community after evidence emerged suggesting that dark energy – the mysterious force responsible for the accelerated expansion of the Universe – could be changing over time, challenging our current understanding of space and time.
According to an analysis by a team of researchers in South Korea, instead of the Universe continuing to expand indefinitely, the galaxies could be pulled back towards each other by gravity, leading to a catastrophic scenario astronomers call “Big Crunch”.
The researchers involved say that the discovery could be one of the most important in astronomy in recent decades. Although their conclusions are contested by other specialists, critics have not been able to completely reject the hypothesis, notes the BBC.
What is dark energy
For decades, astronomers believed that the expansion of the Universe, which began with the Big Bang about 13.8 billion years ago, should gradually slow down under the influence of gravity. This theory was shaken in 1998, when dark energy was discovered – an unknown force that accelerates the cosmic expansion.
Observations of extremely bright supernovae have shown that distant galaxies are not just slowing down, they’re moving away faster and faster. Some theories have even suggested an apocalyptic ending, known as justice “Big Rip”, in which the Universe would expand so much that it would disintegrate even the atoms.
Unexpected data from a US telescope
The controversy began in March after the Dark Energy Spectroscopic Instrument (DESI), located on a telescope in the Arizona desert, provided unexpected results. DESI tracked the motion of millions of galaxies, and the data suggested that the rate of acceleration changed over time, which did not fit the standard cosmological model.
“Now, with this dark energy that seems to wax and wane, we need a new mechanism. It could be a major shakeup for all of physics.” said Professor Ofer Lahav, from University College London, involved in the DESI project.
The “Big Crunch” hypothesis, relaunched
In November, the Royal Astronomical Society published a study by the team led by Professor Young Wook Lee of Yonsei University in Seoul. The researchers reanalyzed the supernova data, taking into account the age of the galaxies from which they originated, and concluded that dark energy has not only changed over time, but that cosmic acceleration may be slowing.
“The fate of the Universe will change. If dark energy is not constant and is weakening, the entire model of modern cosmology is called into question,” Professor Lee told BBC News.
If this force weakens enough, gravity could become dominant and the Universe could collapse in on itself in a “Big Crunch”, instead of one “Big Rip”.
Criticism from the scientific community
Although the study was peer-reviewed and published in a prestigious journal, many astronomers remain skeptical.
Professor George Efstathiou, from Cambridge University, believes the results reflect the complexity of supernovae rather than a real change in dark energy.
“The correlation with the age of galaxies is not very robust. It seems risky to me to apply such a correction,” he said.
However, Professor Lee rejects the criticism, stressing that his analysis is based on data from 300 galaxies and that the likelihood of the results being a coincidence is extremely small.
Meanwhile, two other teams of researchers re-analyzed the original data, tempering the conclusions slightly but not completely eliminating hints that dark energy might vary.
Debate about the fate of the Universe
Hundreds of scientific studies have been published on the subject, and the astronomical community remains deeply divided. According to Professor Robert Massey, Deputy Director of the Royal Astronomical Society, this debate is essential.
“Who wouldn’t want to understand how the Universe began and how it will end? It’s a fundamental question for humanity. People have always been interested in this, whether you look at it from a religious or scientific perspective.” he said.
