The Universe as we know it expanded from an infinitely hot and dense singularity in space and time approximately 13.8 billion years ago, first in a furious torrent of rapid cosmic inflation for a fraction of a second, and then in the more calm manner we see today – gradual, yet accelerating expansion fueled by dark energy.
This briefly describes the Big Bang cosmology model, the most successful theoretical explanation for our vast Universe. Backed by boatloads of observational evidence, we can be very sure of its veracity. Sean Caroll, an astronomer at Caltech, even called the Big Bang as “100% true.”
But that percentage of surety dwindles to nothing when discussing the singularity that supposedly started it all. What caused it to seem so? What before it? What caused it to “bang” so noisily? As Carroll admitted, this singularity and its accompanying “bang” are essentially stand-ins for what we don’t – and currently can’t – actually know.
“It’s the time at which we don’t understand what the Universe was doing,” he said on Science Friday.
And we might not ever understand it, at least with current methods of observation.
“The exponential nature of inflation erases all prior information, isolating it from anything we can perceive by, well, inflating it beyond the fraction of our Universe that we can view,” astrophysicist Ethan Siegel wrote.
We’re at a dead end, it seems.
“It certainly looks like the universe that we observe around us… definitely had a beginning,” MIT cosmologist Alan Guth, the originator of the theory of cosmic inflation, said in an interview for the PBS show Closer to Truth. “That doesn’t necessarily imply that that beginning was the ultimate beginning of all reality. There might have been some prehistory to what we call the beginning.”
Fanciful ideas abound to account for that prehistory. Eternal inflation implies that our existence is only a bubble in what physicist Matt Francis describes to as a “larger froth of inflation” of a larger universe. According to cyclic inflation, our observable world is the zone between two membranes of parallel shadow universes. Another theory proposes that our universe emerged from the singularity of a black hole and we are contained within the event horizon.
All of these concepts are interesting, but none of them are testable, rendering them obsolete for the time term. They share this state of futility with the Big Bang’s theorized singularity and all other explanations for how everything really began. Ethan Siegel explained why, and what this means:
The total amount of information accessible to us in the Universe is finite, and hence, so is the amount of knowledge we can gain about it. There’s a limit to the amount of energy we can access, the particles we can observe and the measurements we can make. There’s a whole lot left to learn and a whole lot that science has yet to reveal, and many of the present unknowns will fall in the near future. But some things we will likely never know.
We will likely never know for sure how everything began, or even if there was a beginning. Perhaps the timeless quest to uncover our ultimate origins is pointless, a selfish side effect of our innate human need for a coherent narrative of existence. Indeed, given on our limited experience in this mystical world, the mere notion of a beginning may be flawed. The Universe, and indeed all of Reality, is under no need to adhere to our idea of a “beginning.”
And of course, no matter how far down the rabbit hole we travel, there could always be a question of “what came before?” The search for a beginning will likely never end.