Quantum Physics Laws Might Erase the Universe That Preceded Ours

Is it possible that our universe will continuously expand, then contract back into a small point, repeating the Big Bang? According to recent mathematical analyses, the laws of physics suggest that such cyclical behavior is unlikely.

A pivotal element in the concept of a cyclical universe is the “big bounce,” which reimagines the beginning of our known universe as an event following this bounce rather than the traditional Big Bang. The Big Bang is characterized by incomprehensibly dense concentrations of matter and energy where gravity becomes intense enough to alter physical laws, leading to an infinite outward expansion. Conversely, a universe beginning with a big bounce allows us to explore realities beyond what we perceive as the inception, potentially emerging from another universe that undergoes contraction into an extremely dense state, but not necessarily a singularity.

Thus, the essential inquiry about whether time began with a singularity becomes crucial for understanding our universe’s past and future. If the big bounce indeed marks the inception of our universe, it may also inform its prospective trajectory. The initial idea proposed by Oxford’s Roger Penrose in 1965 revolved around the inevitability of collapse under general relativity, the prevailing framework for understanding gravity, particularly related to black holes, which also represent scenarios where gravity can disrupt the fabric of space-time. Penrose concluded that if gravity intensifies sufficiently, singularities cannot be evaded.

Currently, Raphael Bousso of the University of California, Berkeley, has introduced critical insights enhancing these findings by elucidating the quantum properties of the universe.

While Penrose’s arguments didn’t incorporate quantum theory, Bousso indicates that prior explorations by Aron Wall from Cambridge University considered scenarios of very minimal gravity. However, Bousso’s analysis does not limit gravity’s intensity and asserts that it “decisively excludes” the possibility of a circular universe, reinforcing the singularity associated with the Big Bang as an unavoidable outcome.

Onkar Parrikar from the Tata Basic Research Institute in India asserts, “This represents a significant generalization of Penrose’s original theorem, further extended by Wall.”

Chris Akers from the University of Colorado, Boulder points out that this marks substantial progress, as it is “far more effective in quantum physics” compared to earlier studies. He suggests that this new research will impose stricter constraints on larger bounce models.

Bousso’s computations hinge upon a generalized second law of thermodynamics, expanding the conventional second law to address entropy behavior around black holes. This advanced perspective has yet to be rigorously validated, according to Surjeet Rajendran at Johns Hopkins University in Maryland.

In 2018, Rajendran and his team crafted a mathematical representation of the bouncing universe that circumvented constraints imposed by Bousso’s theorems. However, their model included more dimensions of space-time than have currently been observed, leaving some uncertainties unaddressed.

Akers emphasizes, “Understanding our universe’s history is undeniably one of the most crucial scientific endeavors, and alternative models like big bounces should be thoroughly evaluated.”

Jackson Fris from the University of Cambridge mentions that in bouncing scenarios, quantum effects might bolster the universe’s rebound from its dense states. Investigating these scenarios can further our understanding of how quantum gravity theory, which melds general relativity and quantum mechanics, may reshape our conception of the universe. “If quantum gravity is indeed essential for a comprehensive explanation of a black hole’s interior or a big bang,” he notes.

According to Rajendran, one of the most vital methods to ascertain whether our universe experienced a spatial bounce is through gravitational wave observations. These space-time ripples could carry identifiable signatures of the bounce but currently exist in frequencies outside the detection capabilities of existing gravitational wave observatories. Future generations of detectors may capture these frequencies, although the realization of several planned upgrades to U.S. detectors may be uncertain due to proposed budget cuts from the previous administration.

“It is a matter of whether there exists a universe capable of generating a signal strong enough for detection, and if our current world permits scientists to perform those experimental constructions,” Rajendran states.