The universe may not have begun with a big bang, physicist Juliano César Silva Neves says. If so, how did the universe come into existence?
An illustration of the possible birth and evolution of the universe [Image by NASA/WMAP Science Team]
The Big Bang Theory is perhaps the foremost theory that offers an explanation for how the universe was born. According to this theory, there was a small singularity that expanded over a span of 13 billion years, eventually becoming the universe that we know today. We don’t have the technology to directly observe the circumstances of the universe’s birth, but what we do know about it comes from mathematical models.
While this explanation is the most popular, there are scientists who have put forth their own theories on the origins of the cosmos that challenge the prevalent ideas. According to a new study, the universe actually undergoes a cycle of contraction and expansion. Time doesn’t have a beginning; instead, this present expansion was preceded by a contraction.
A singularity lies at the end of the funnel that represents a black hole. Near the mouth of the funnel lies the event horizon.
"My proposed cosmological model, of course, acknowledges the expansion of the universe and also other known phenomena such as cosmic radiation,” explains Neves. “For me, the main issue is the Big Bang and the state of initial singularity. That is, the [theorized] first stage of the universe's existence, a state in which the physical and geometric quantities that figure in Einstein's theory of relativity, do not have a set value.”
Neves doesn’t think that the Big Bang actually ever happened. The Bing Bang Theory came into existence in the 1920s, after astronomer Edwin Hubble discovered that most of the galaxies in the universe were moving away from each other at an increasingly rapid rate. About two decades later, using Einstein’s theory of general relativity, scientists were able to build a model of how the universe evolved after the Big Bang. The model gave rise to three possibilities: infinite expansion, the permanent stagnation of the expansion, or the Big Crunch. The Big Crunch says that the mass of the universe exerts a gravitational attraction, which causes an inverted process of retraction.
According to Neves, if we remove the presence of a singularity at the beginning of the universe’s timeline, we bring back “the bouncing universe on to the theoretical stage of cosmology. The absence of a singularity at the start of spacetime opens up the possibility that vestiges of a previous contraction phase may have withstood the phase change and may still be with us in the ongoing expansion of the universe."
An artist's impression of a black hole [Photo by Victor de Schwanberg/Science Photo Library]
But what is a singularity, anyway? A singularity is a point in space-time which contains a tremendous amount of mass in an infinitely small space. Science fiction writers love singularities, but physicists? Not so much. One kind of singularity can be found behind the event horizon of a black hole, while the other kind is the theoretical one that supposedly birthed the universe. Whichever kind it is, however, the nature of singularities is a confusing point of contention among physicists.
Neves uses black holes as the jumping-off point in his investigations into his “bouncing universe”. He thinks it’s possible that there are black holes in the universe that came from the contraction phase prior to this expansion phase. If those black holes--or “scars” from the previous contraction, as Neves calls them--are ever found, they may support Neves’s hypothesis.
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