According to a new research, the universe will soon stop expanding to ultimately collapse into itself, annihilating all that it contains. The authors of the study, Nemanja Kaloper and Antonio Padilla, have proposed a cosmological collapse mechanism, including an account on dark energy, to explain the happening. According to their calculations, the event might occur in a few tens of billions of years from now – this may sound far away along the timeline, but to the physicists, it is “too soon”. The study lays particular emphasis on how the mechanism can bring answers to puzzling questions in physics. The findings have been published in the journal Physical Review Letters.
The mechanism of the cosmological collapse posited by the authors include an explanation relating to dark energy.
“The fact that we are seeing dark energy now could be taken as an indication of impending doom, and we are trying to look at the data to put some figures on the end date,” Padilla said in a statement.
“Early indications suggest the collapse will kick in in a few tens of billions of years, but we have yet to properly verify this.”
It seems that the mysterious dark energy mentioned is causing the universe to expand in an accelerated manner. Could it be that the predicted vacuum energy density of the universe (the alleged reason of the expansion) as per the cosmological constant problem is larger than what is thought?
“I think we have opened up a brand new approach to what some have described as ‘the mother of all physics problems,’ namely the cosmological constant problem,” Padilla said. “It’s way too early to say if it will stand the test of time, but so far it has stood up to scrutiny, and it does seem to address the issue of vacuum energy contributions from the standard model, and how they gravitate.”
The new mechanism puts forward that the origin of the universe is linked with particular conditions at the beginning that account for its evolution to the current state of acceleration. Accordingly, the universe will continue on this journey leading to it collapsing. In this case, when the collapse trigger has the upper hand, the collapse occurs in a period of “slow roll” that gives way to the accelerated expansion witnessed today. Consequently, the universe will stop expanding, reaching a turnaround point where it will start to shrink and close in on itself.
For when is that ultimate collapse?
The universe is now around 13.8 billion years old. We are currently in the accelerated expansion period. As per the new mechanism, this period will extent until at least this time. The collapse time might be delayed by a reasonable slope with a very tiny positive value of around 10 to the power of -39, according to the equation. Gradual slopes imply that the universe is evolving as a very slow pace.
The slope is “technically natural”, according to the scientists. The mechanism purports that it alone controls the evolution of the universe, and the scale of the accelerated expansion.
“The ‘technically natural’ size of the slope controls when the collapse trigger begins to dominate, but was it guaranteed to give us slow roll and therefore the accelerated expansion?” Padilla said. “Naively one might have expected to have to fine-tune some initial conditions to guarantee this, but remarkably that is not the case. The dynamics of vacuum energy sequestering guarantee the slow roll.”
“There is much to do,” Padilla said. “Right now we are working on a way to describe our theory in a way that is manifestly local, which will make it more conventional, and more obviously in keeping with some of the key principles behind quantum theory (namely, linear superposition). We would also like to devise more tests of the idea, both cosmological and astrophysical.
“Over the longer term, we would like to understand how our theory could emerge from a more fundamental theory, such as string theory. It is also important to ask what happens when we consider vacuum energy corrections from quantum gravity.”