Journey to the edge of the observable universe Review
27 February 2023
In the very next instant, light from the beginning of the universe began to spread across the cosmos. The universe itself was also expanding at this point. After the initial burst, the universe’s inflation slowed down, but dark energy’s influence has kept the rate of expansion steady ever since.
In essence, the universe has been expanding at an ever-increasing rate ever since its inception. Since the Big Bang, the distance between the oldest photons we can see has been somewhere between 45 and 47 billion light-years. That indicates that our observable universe is approximately 93 billion light-years across (within a few light-years of each other). Quarks, quasars, stars, planets, nebulae, black holes, and anything else we could possibly observe are all contained in these 93 billion light-years. However, the only light that can be observed in the universe is that which has already reached us.
If the universe is only 13.8 billion years old, how can it be 93 billion light-years across? Light hasn’t had time to get that far, has it? Understanding this aspect of physics is ultimately the key to understanding what lies beyond the observable universe’s edge and whether or not we will ever reach it.
To put this into perspective, according to special relativity, objects that are close together cannot move at a speed greater than the speed of light; However, when the space between two objects is expanding, there is no such law for objects that are extremely far apart. In short, the distance between objects is expanding, causing them to fly apart at incredible speeds, not that they are traveling faster than the speed of light.
In the end, this means that we would only be able to reach the outer limits of the observable universe if we could either 1) travel faster than light (which the majority of physicists believe is impossible) or 2) transcend spacetime (through wormholes or warp drive, which the majority of physicists also believe is impossible).
The entire universe is at least 1023 times larger than the observable universe, according to the theory of cosmic inflation.
We are missing a lot of the universe there. So, exactly what are we lacking? What is beyond the universe that can be observed? Unfortunately, we have no idea what lies beyond the scope of the universe that can be observed because we are unable to see or measure it. However, we have a number of hypotheses regarding the great unknown.
ENTERING THE UNKNOWN Despite its oddity, this initial concept is one of the easiest to comprehend. Space, according to astronomers, may be an infinite expanse of the universe around us, distributed roughly in the same way as it is in the observable universe. This makes sense. After all, it makes no sense for one region of the universe to be different from the rest of the universe. And to be honest, who could possibly imagine a universe with an end and a huge brick wall at its edge?
In this way, infinity makes sense in some ways. However, “infinity” implies that beyond the observable universe, you will eventually discover everything that is possible—not just more planets, stars, or other forms of material. Every. Possible. Thing.
That means that, if this holds true and we follow it to its logical conclusion, there is a you who is only slightly different from you in every possible way (one is an inch shorter;) and there is another person who is identical to you in every possible way. One died after being struck by a bus five years ago; One finger is missing, for example). In point of fact, this “other you” might be currently reading this article; The only thing that separates them from you is that they only picked their nose, whereas you did not (or did you?). It seems absurd to entertain this idea. But then, it’s hard to think of infinity.
Dark flow is the subject of another theory. Astronomers discovered something very strange and unexpected in 2008: a massive stream of galactic clusters moving in the same direction at over two million miles per hour. One possibility is: Massive structures with gravitational pull that exist outside the universe that can be seen. The structures themselves could be absolutely anything: Gravitational forces from other universes are being funneled through astonishingly massive accumulations of matter and energy on scales we can hardly imagine, or even bizarre warps in space-time. We simply do not have any idea what these enormous objects might be. Notably, recent studies claim to have disproved the dark flow model, but this is still up for debate.
A universe of universes is another option. In the midst of a vast array of other bubbles, a small “bubble” may contain our universe as a whole, according to some. This is known as a “multiverse” in theory. It’s interesting that the idea says that these parallel universes can meet; gravity can flow between them, and if they meet, a Big Bang like the one that created our universe could happen.