Well, this is not only NOT IMPOSSIBLE but one of the many possibilities being explored.
But possibilities aren’t enough. Evidence is everything!
So, the real question is: do we have any evidence or strong theories that hint at an everlasting universe that has always existed?
Let’s check out what we already know about the universe.
Image Source: https://www.smithsonianmag.com/science-nature/can-physicists-ever-prove-multiverse-real-180958813/
The Beginning Paradox
Before we dive into the physics of this question, let’s take a quick stock of the philosophy and psychology of it. I’ll keep it brief.
From your question, you’re clearly inclined to believe that our universe had no beginning at all, and it always existed. Perhaps it brings a sense of comfort, knowing that this universe has always existed.
We humans have always abhorred change since the prehistoric era. In those primitive times, a change almost always meant death. Moving to a different place meant new, unknown predators and threats. A changing climate meant the wrath of the weather. You get the gist.
So, we hate change. A universe that had a beginning will also present the possibility that it might have an end. An eternal universe obviously brings a sense of comfort. It doesn’t matter that none of us would live beyond our own puny lives to be affected by the universe either way.
While the emotional side of our mind seeks – perhaps even needs – a permanent universe, the rational side abhors it.
Our logical brain thinks about the universe’s beginning and wonders, “Well, if it began at some point, what came before it?”
The problem with this question is that it does not have an intuitive answer. The Big Bang Theory tells us that time began at the Big Bang. There was no “before” it.
Our rational minds cannot comprehend it. We cannot imagine something happening and there being nothing before it. If there was no time before time, how did time choose to begin at the point of the Big Bang? If something triggered the Big Bang, it clearly must have happened before the Big Bang, and ergo, before time’s creation, but how can that be?
For these questions, there are no intuitive answers. We have mathematical answers that explain how time and space came into existence at the same time. In physics, time is just another dimension like the X, Y, and Z axes. Just as they have a ZERO point, so does time. Pure and simple, but not intuitive.
In a nutshell, whether the universe had a beginning or not, the knowledge is not going to bring you any peace, whatsoever. Only more questions. And we’ll never be satisfied with mathematical answers alone.
Whoever said knowledge sets you free!
Why We Think the Universe Began 13.8 Billion Years Ago?
Because the universe says so!
In 1927, a brilliant Belgian priest and physicist by the name of Georges Lemaître solved Einstein’s equations to make a theoretical prediction that the universe should be expanding.
(Don’t be so surprised by Lemaître’s seemingly conflicting credentials. Many have been men of both God and science. Lemaître, Mendel, and Copernicus, to name a few)
Two years later, in 1929, Hubble provided empirical evidence that supported Lemaître’s theory. So, for the first time, we knew for sure that the universe is expanding at enormous speeds – much like particles in an explosion.
However, we still didn’t know when the universe began. We did, however, know that there would be leftover evidence of the Big Bang. And we accidentally discovered it in 1965 as the cosmic microwave background. It helped us broadly estimate the universe’s age as 10-20 billion years.
The most accurate estimates of the universe’s age would have to wait until the 21st century. The Plank satellite from ESA provides us the most accurate data on the age of the universe at the moment, and it’s 13.8 billion years, give or take 20 million years or so.
So, you see, we went back in time. Today, we have an expanding universe (much like an explosion), and we went back in time to calculate when the expansion began. Using leftover radiation from the Big Bang, we can calculate the age of that radiation. That’s how we know the universe is 13.8 billion years old.
But Could the Universe Exist Forever, Despite the Big Bang?
Before I get into this speculation, I need you to understand that “could” doesn’t mean “is.”
That said, serious scientists are working on several potential models of the universe in which time didn’t begin at the Big Bang. We can take a look at some of them.
Heat Death and Spontaneous Inflation
Heat death is the most likely endgame for our universe. Everything in this universe would eventually be destroyed, either through decay or explosive destruction. Even black holes, free interstellar gas, rocks, and even protons. Everything will turn into radiation.
After a long time – so long that it’s pointless even to discuss the number – the universe will cool down to its final energy state, hitting infinitesimally close to absolute zero temperature.
In such a vast, empty, cold, and dead universe, quantum tunneling and quantum fluctuations can create a new Big Bang and an entirely new universe with its own laws of physics.
Maybe it happens in several far-flung patches of the universe – each patch so far away that no two will ever experience any kind of interactions for all eternity, resulting in the creation of multiple bubble universes – a sort of multiverse in our own universe.
Now, here’s the big question: what if our own universe and its Big Bang are part of a bigger multiverse?
Maybe creation is just nested multiverses inside other nested multiverses, each with their own Big Bang. In such a scenario, time could have a beginning or not. We have no way of knowing.
If you think this is just intellectual masturbation, you’re probably right. But that doesn’t mean scientists don’t do it, or that it can’t be a reality. You’d be surprised how much of theoretical physics is just that!
Cyclical Universes
I’m not going to touch upon every cyclical universe theory because there are many, and none of them offer enough credibility as a viable explanation for what we know about the universe. In some cases, their predictions cannot even be measured.
The biggest problem with most cyclical universes is that they require entropy to reverse one way or the other, which we know isn’t possible. Some models predict the universe is a series of Big Bangs and Big Crunches, while others opt for a bouncing universe.
Still, Roger Penrose’s Conformal Cyclic Cosmology theory deserves a mention because it takes a different approach. It’s close to the heat death scenario we discussed earlier. Instead of several Big Bangs happening in isolated regions, Penrose posits that each heat death of the universe results in the Big Bang of a new one. So, it’s just a never-ending cycle of Heat Death-Big Bang-Heat Death for the universe.
Interestingly, Penrose’s model posits that in the heat death of the universe, time and space will lose all meaning. Hence, each new Big Bang could be interpreted as the beginning of time itself for that universe, which he calls an aeon.
If we exist in one such aeon, time began at the Big Bang as far as our universe is concerned. Saying that there existed time before it, or that it would exist after the heat death would make no sense, because each aeon is self-contained - connected only mathematically. There is no time continuity here.
Evidence of an Older Universe
If we’re able to find evidence of the Big Bang that happened 13.8 billion years ago, is it not reasonable to expect to find evidence of an older universe or time before the Big Bang?
Well, you’re not alone in thinking that.
If something existed before the Big Bang, it would have affected the Big Bang itself. This influence would have been amplified during the inflationary stage of the Big Bang, resulting in clear evidence of an earlier universe.
Do we see such anomalies in the Cosmic Microwave Background, which is the leftover radiation from 380,000 years after the Big Bang? Well, we have, but those anomalies can be explained by other phenomena and are not so inexplicable that they could be attributed to an earlier universe or time.
So, the search is on and we may or may not find such evidence in the future.
Final Thoughts
We know a great deal about the universe, but we still know very little about it.
So, it’s possible that the things we know to be true for now would be proven otherwise by future discoveries.
That doesn’t mean we start questioning everything we know, just because we don’t like it.
For now, there’s mounting evidence that the universe is 13.8 billion years old. Until we find evidence contradicting this, it’s better to speculate and titillate our minds, but not get consumed by our need for “more” to start believing unsubstantiated theories over proven ones.
There’s a reason why theoretical physicists have a reputation for being mad geniuses. They live and breathe the unsubstantiated before it “becomes” real!
But most amateurs going down this rabbit hole just become mad! Let professionals do what they do best. We’ll wait for the answers.