EVERYTHING IN OUR UNIVERSE HAS A LIMIT

 

Everything in our universe has a limit. It may seem obvious, but it is something worth-considering. If everything has a limit, than there’s no such thing has “infinity”. Something without a limit cannot exist, because it is incompatible with our own reality. We know that there’s a limit to how cold something can get: that’s 0 Kelvin degrees, the minimum possible temperature. We know that there’s a limit to how fast something can go: that’s 300 000 000 meters per second, the speed of light. And we know that there’s a limit to how much of the Universe we can see and interact with.

It may seem absurd, but it’s true: what we see when we look at the sky is just a tiny part of the Universe. And it’s not just a matter of human sight. While it’s true that we humans can perceive light in a very limited way, even the most powerful telescope still has its limits. That’s because of the nature of the Universe itself. The Universe is not still. It is ever-expanding. Its expansion started with the Big Bang, and continues to this day. And the more Time passes, the faster the Universe expands. We do not know why, so we came up with the concept of Dark Energy: a mysterious form of energy that accelerates this expansion.

                                                                        

Because of this, there’s a Cosmological Horizon around us. Everything behind this horizon travels faster, relatively to us, than the speed of light. They are not technically faster than light, but the expansion of the Universe causes them to move faster than it. So their light will never be able to reach us, and we’ll never be able to perceive them in any possible way. To us, it is as if they did not even exist. The Horizon has the shape of a circle, and its diameter is 8.8 × 〖10〗^26  meters. Even if the Universe was infinite, we couldn’t know it. We are trapped in this finite pocket of the Universe.

And it doesn’t end here. In reality, 94% percent of stars of the Observable Universe have already passed the Horizon. We can see them because light needs time to travel through space. What we see now is just the light those stars emitted millions of years ago, before passing the Horizon. We are, in a sense, looking at their past selves. The majority of the Observable Universe is already out of our reach. The remaining 6% percent makes up the Local Group which is part of the so-called Laniakea Supercluster. Everything in the Supercluster is technically reachable. However, it is very unlikely that we’ll ever be able to develop the technology necessary to perform such an impressive feat.

                                                                           

The true scope of our reach is even smaller: even with sci-fi technology, the nearest galaxies, like Andromeda, would still be very difficult to reach. So, we’ll probably never leave the Milky Way, our home galaxy. But this may not a problem for us: our galaxy is 200 000 light years in diameter, and contains around 300 billion stars, with many more planets orbiting around them. It is a lot. Seriously a lot. It would take us an impressive amount of time to reach and, possibly, colonize them all. So, who cares about the rest of the Universe? Why should we, when we have all of this to think about?

YURI, 4sc