A lot can happen in a universe in 13.8 billion years, and scientists have indeed kept busy studying the wide breadth of events that shaped our cosmos.
But one event that had seemed widely accepted — the Big Bang theory — has come under close scrutiny by some cosmologists. They call into question not just when the universe started but also how it all began. So, how did the universe start? Others leap beyond the theory altogether and claim there was no beginning; the universe has always been there. Another camp believes there could be several universes, and we just happen to be in the one with pizza and beer.
The history of the universe is a product of some hard science, but it also has many “wiggle room” theories to account for unknown and inexplicable phenomenon. So, it shouldn’t come as a surprise that not everyone buys the idea of a big bang-type spark to life as we know it. Apparently, there’s more “there” to the out-there of our universe.
How Did the Universe Start?
As the title of the popular TV show “Big Bang Theory” illustrates, the idea of an explosion of sorts to produce a universe has taken hold as the dominant concept of how our place of existence started. When schoolchildren learn about cosmic creation, they are usually taught the underpinnings of the Big Bang.
It’s posited that immediately after this big spark, we would have seen a 10 billion-degree sea of neutrons, protons, electrons, anti-electrons, photons and neutrinos cooling off. As the piping fresh hot universe cooled, either the neutrons decayed into electrons or protons, or they combined with protons to create an isotope of hydrogen. Further cooling led to more combinations: electrons merged with nuclei to form neutral atoms and also change what was a murky celestial backdrop into a transparent one that could be later discerned by modern scientists. Those photons formed an afterglow that’s known as cosmic background radiation. That’s the part of this creation show that can be observed today.
“The first three minutes of the universe is an exciting place,” said Leslie Brown, an associate professor of physics at Connecticut College. “We’re looking at the guts of a star. We’re looking at thermonuclear fusion, and that’s where our elements come from. The two elements made during those moments are hydrogen and helium.” Those elements, in fact, comprise nearly all of the nuclear matter in our universe. Scientists say the abundance of hydrogen and helium helped determine the speed with which the universe expanded.
And that’s another chapter in the Big Bang story: just as quickly as the universe formed, it rapidly expanded, as if a newborn suddenly filled out to the size of an NBA power forward. To put it into perspective, try to picture the infinite jumble of stuff that was created after the Big Bang. That pack of stuff has a defining term— the “singularity”— that could also be the name of a rock group. The analogy is fitting. Like any rock group that is full of distinctive personalities, the neutrons, protons and anti-electrons that made up the singularity were perhaps too homogeneous for their own good. The singularity separated and moved on — far on — only a second or so after the Big Bang. (And people think the Beatles broke up too soon.)
Thanks to a temporary shot of dark energy, the universe expanded faster than the speed of light, separating all the stuff and placing stars and planets in particular places, giving us the home we have today and explaining why all of the radiation around us smoothed.
Determining What Came Before the Bang
The Big Bang story satisfies many people, but not all. After all, with much to review in a 13.8-billion-year history, there is a lot of room for more questions and countering opinions. Did anything happen before the Big Bang? Did something really come from nothing? It’s a celestial wrinkle on the age-old chicken-or-egg question.
First, it’s difficult to even determine what happened in that flash of time after the Big Bang — the instances before the pieces of the singularity went their separate ways. Scientists can confidently piece together what happened 1 trillionth of a trillionth of a trillionth of a second after the Big Bang but are hard-pressed to measure that sliver of time before then. That’s largely because after the singularity ended, all of those free electrons would have caused the photons (or light) to scatter and create an opaque backdrop. “If you go back that far, the temperature is so hot, everything is ionized,” Brown said.
So why would cosmologists try to take an even bigger leap and attempt to learn what happened prior to the Big Bang? For that matter, how can they even determine if there was a pre-Big Bang existence? Well, for one, they’re not taking too much of a leap because as with anything as old as the universe, nothing is an irrefutable fact, not even the original singularity. The science allows for meaningful theories, mild conjecture and even wild stabs in the dark. It can all seem confusing, especially when you study theories that diverge from the concept of an initial singularity. Those theories are attempting to go beyond an accepted starting point, so such thinking seems counter-intuitive, like trying to envision your life before your cells formed in the womb.
“The singularity in space-time,” Brown said, “causes humans problems because we want to know what was before that. It’s hard to think there was nothing before that.”
Added David Mattingly, an assistant professor of physics and astronomy at the University of New Hampshire: “The conclusions we draw about the universe are speculative and interesting philosophically. But you have to realize there is no confirmed scientific belief this is the way it all began.”
Drinking Coffee in Another Universe
With no universal consensus on the universe, a cold war has started among some cosmologists. As Brown and Mattingly can attest, and as The Atlantic reported, some of the pioneers of the theory of cosmic inflation have continued to flesh out their viewpoint since first publicizing it in the 1980s. But one of those cosmologists, Princeton professor Paul Steinhardt, left the group, much as matter left the initial singularity. In 2017, Steinhardt and other contemporaries argued that inflation can’t be considered an empirically scientific theory. Instead, they say inflation could unfold in so many ways that a single observation can’t be a gold standard. (To needle those original inflation proponents, Steinhardt and his cohorts said the inflation advocates actually know the error of their ways. The inflation camp got as hot as the sun over that charge.)
An idea that popped out of the inflation theory is what drove Steinhardt to leave his inflation friends. That idea holds that we are in one of many universes. The models supporting inflation contend it never really stopped or, for that matter, never really began. Inflation, the thinking goes, is eternal. As The Atlantic explained, while inflation largely stopped in the section of space we can observe, there are areas in the universe where the power of inflation creates another universe with its own physics. There, another pocket forms and you have yet another universe.
Tufts University physics professor Alex Vilenkin expounds on the infinite multiverse theory by offering that a replica of a person is on a replica of Earth somewhere else. But there are twists to that theory, as a Stanford Magazine article from 2007 explained in a way that holds true 13 years later: In another universe, you are the same but are speaking a different language. In another universe, you’re not a writer but a cancer researcher. In some universes, you’re nothing at all because there is nothing at all there.
A Field That Keeps Cosmologists Busy
Renown theoretical physicist Stephen Hawking had fun with the history of the universe by claiming it’s a history unlike any other because it has no start and end dates. There was no Big Bang or even a pre-Big Bang because, Hawking told an audience at the Vatican in 1981, there is no beginning and there will be no end. “There ought to be something very special about the boundary conditions of the universe, and what can be more special than the condition that there is no boundary?”
Collaborating with physicist James Hartle, Hawking compared the universe to a shuttlecock. As QuantaMagazine describes: “a shuttlecock has a diameter of zero at its bottommost point and gradually widens on the way up.” Like a shuttlecock, “the universe, according to the no-boundary proposal, smoothly expanded from a point of zero size.”
This “wave function of the universe” encompasses the past, present and future all at once. For those who believe in the divinity of a higher power, Hawking and Hartle’s theory squashes any notion of creation, a creator or any transition from a time before.
All this speculation keeps Brown and Mattingly enthralled with their work and fuels their and many others’ drive to continue looking for answers. “It’s cool to think about,” Mattingly said. “Does the universe go on forever?”