According to a new study, the expansion of the universe will stop surprisingly soon, sometime in the next 65 million years. After that, it will begin to contract in a process that will last billions of years. (Expanding and contracting universe theory).
The study - published in the scientific journal PNAS ( https://www.pnas.org/doi/full/10.1073/pnas.2200539119 )- states that the model "fits naturally with recent theories of cyclic cosmology and conjectures about quantum gravity" although it is not observable at the moment on a practical level. His model also agrees with the prevailing model of dark matter, where dark energy makes up 70% of the universe.
Albert Einstein was the first to conclude that the vacuum as such does not exist and theorized that there was a "repelling energy" which he introduced into his model as the Cosmological Constant, integrating it into the fabric of space-time. Observations from the Hubble telescope in 1998 showed that the expansion of the universe was not only real but was also accelerating, finding evidence of the effects of this repelling force, which he named dark energy. The discovery of the acceleration condemned the universe to swell faster and faster until it was extinguished in the night of time. Its final state, says one of the most popular models to date, will be the thermal death of the universe, a state in which it is impossible to sustain the processes that create new stars and maintain the entropy of the cosmos.
But the authors claim that the dark energy that today accelerates the expansion of the universe - which they call "quintessence" - is not a constant, but a value that decreases with time.
The result of their new mathematical model is that this decreasing nature of dark energy "will bring the acceleration to an end and a smooth transition from expansion to a slow contraction phase."
As another scientific publication at Live Science ( https://www.livescience.com/end-cosmic-expansion), University of British Columbia physics and astronomy professor Gary Hinshaw - who has no connection to the study's authors - nothing about this new model is controversial or implausible. In fact, it fits perfectly with everything we have observed so far.
According to Hinshaw, "to their surprise, the dark energy in their model can decay with time. Its strength can weaken." The model shows that eventually the antigravitational property of dark energy disappears and it transforms into something that looks more like ordinary matter. Its repulsive force, the study says, may have begun to decay rapidly billions of years ago.
Interestingly, this scientific theory links with the thinking of the ancient philosophers of classical Greece, who spoke of a cyclical universe (and cyclical time). It is worth reflecting on this.
