It all depends on how you measure time. For our current understanding, the universe is just a small fraction of a second old. However, that may change in what’s known as the Big Bang Theory, when the expansion of space (the expansion of time, in a way) allowed for the creation of an infinite universe. And that universe is now estimated to be 11 billion years old.
So, what has changed since we started using the Big Bang as a starting point? In recent years, scientists have made an excellent case for saying that the Big Bang is part of our very universe. In a 2009 paper, David Deutsch and co-authors pointed to a surprising number of features in our cosmos in which “the Big Bang had already taken place.”
They point out that the “cosmic microwave background” — a relic of the Big Bang — contains a pattern at a few hundred thousand different places in the universe. And this is only the first of many clues to the structure of our universe, even before we can begin to grasp what it has done up to this point.
Why should the universe have this many features as we know it? In most of the universe, scientists say, “the first step to the most complex structure is the most delicate, and so is the first step in all things.” That’s not so in quantum mechanics. “There is no difference, at all, in complexity among the structures where things start,” says John Stewart of the University of Sydney. “The process of the universe’s evolution simply is itself complex.”
In other words, everything in the universe can be broken down into a few fundamental building blocks — in some cases, just a few fundamental particles — followed by the process of their formation into increasingly complex structures, according to Stewart and other theorists. “So this ‘Big Bang’ is, in a way, a process,” he says.
So why have they been finding lots of similarities among various features of the universe? It’s possible that many of the features were already present in the earliest moments of the universe. Or it may be that the process of creation itself has led to new features as it evolved. Whatever the case, “the most important conclusion we can draw from it,” says Stewart, “is that the universe, in one sense, is what we expect it to be.
What does it mean when scientists say the universe is always expanding?
The expansion of the universe, the notion that there is always something there that we haven’t noticed yet, that is one of the most striking ideas in cosmology that is not directly derived from Einstein’s equations. And in its simplest form, it is something like, I don’t know, you and I are walking on the surface of the Earth, and we look out, and the horizon is at an infinite distance away. And then I look out and see the sun and moon are not at the horizon at the same point. And that means we are expanding.
And then there had to be a first cause to this expansion. And it turns out that one of the great contributions to cosmology that we can take from this information is a new understanding of this first cause. It turns out, after quite a bit of argument—and the arguments are very strong—that the only way we could avoid that there had to be some underlying cause that is not quantum mechanics, which is the basis upon which we think about gravity. That underlying cause had to actually be supergravity or some aspect of Einstein’s equations about how the universe is expanding.
And it is a stunning realization that these equations are not right for describing the universe as it was, but we’re not looking at the universe at all. Instead, the universe is really expanding in a sense that we are not aware of and we should be aware of.
And so we actually are just observing the expansion. And so we’re really not aware of it. And that is one of the profound implications of this work and the work of others. We now see that everything in our universe seems to be expanding because the universe is expanding. The same way that you and I are watching television or watching the news, the universe is also watching us.
The only other things around us are the things that actually interact with us. And that tells us that the universe is indeed expanding, as it is expanding in the sense that I’ve described it. The universe is expanding and we are the only things we’ve ever seen that are moving.
Why do blackholes exist?
In short, a blackhole is a singularity, in the sense that it encompasses not the spacetime itself, but spacetime within its region of focus. The only way an observer can know that two events are simultaneous is if the event is immediately seen to be simultaneous by all observers; for example, by the instant the electron is emitted from the blackhole and all other observers at this point are “on” the same quantum event. (The “entangled” nature of quantum information makes it very easy to see that entanglement is a requirement for “being simultaneous”; one that any observer has a reason to know to exist.)
So how did we get such massive blackholes in the first place? In quantum theory, a blackhole is simply the region where the wave function is “entangled”, or “cannot separate”. This has no physical implications—in fact, it is often said that it has only physical implications in our own universe (where I was originally reading about quantum field theory). It is just because we do not yet understand the laws of quantum mechanics enough to make the generalization necessary to explain the phenomenon of blackhole formation, but that doesn’t mean there wasn’t a time before quantum theory when such a feature of quantum theory was not possible, and we should study these events as it appears today.
One way to understand how the universe can be made to be “entangled” is by supposing that blackholes are the “matter” that makes up our “matter-antimatter” universe, where matter-antimatter pairs in the opposite sign cancel each other out. If this is true, then by forming blackholes, “quantum gravity” is just like matter-antimatter, as it is just matter-antimatter in an area in its own right. In this way, blackhole formation is just matter-antimatter swapping in a vacuum, just as matter-antimatter “fission energy” in an atomic nucleus occurs.
The other way to understand how blackholes and antimatter matter could be created is to assume that they are the result of the “collision” of supermassive “holes” in a “hyperboloid” configuration, with the two objects in the hole merging when they overlap! Such a scenario may sound preposterous from a “conservation of energy” standpoint, and we’re talking about a phenomenon that we may never understand and it is
The most important conclusion we can draw from it is this.
What happens when you put all the known universe’s matter into a box that is still growing? What happens when you pour water into an already full box? You get a bigger box. How can it be that everything comes from one place? And yet the universe is big enough for each of us to fill it—and yet, despite its vastness, it has always appeared to have been growing at an ever-greater speed. “We are going faster and faster, and yet the overall speed seems to have remained constant,” says John Stewart of the University of Sydney, “Our intuition, the sense of how the universe is expanding and growing apart, seems to be wrong, but I have to admit that when my co-author and I first did this, I thought too that it would be something that would take time.” Stewart found none that actually argued against the idea that the universe grew by a constant rate throughout its history. (For this reason, we tend not to talk about cosmic acceleration.)
But there seems to be a growing consensus that, whatever the case, it will be some kind of acceleration, even though it is still a bit of a head-scratcher to most people. But now, after all these decades of measuring this thing known as inflation, Stewart and co-author John Ellis have settled on a solution, which they’re using to make their model more robust.
Their model involves the existence of some hidden variables within the inflationary model that explain why we are seeing patterns in those inflationary images. We should not just accept this at face value, as it would be absurd to believe that inflation created everything we know of—but Stewart and his co-authors have been doing what they can to make sure their models can handle this. As he puts it, “we try to be very rigorous in what we’re saying.” When we first began working on this project a few years ago, the most reasonable explanation we found available to us was that the universe had only experienced a fraction of its first expansion, and that a huge amount of new energy would be required to continue that process exponentially over billions or trillions of years. But when Stewart was asked what could explain the speed with which the expansion was happening today, he admitted the best idea that had come to him was more of a joke than evidence.
In conclusion, given our limited technology and lack of deep space travel, evidence is still hard to come by. Until we reach warp speed, we will have to rely on the technology we have, as well as the minds of our greatest scientist. Until then, why not theorise and debate this ever so growing and interesting subject. After all, its debates like these that drives humanity to the stars.
To learn more about the universe we recommended taking a visit to New Scientist!