The Universe Is Still Expanding: What Does It Mean?
225The universe is a very big thing, but exactly how big is a big up for grabs, and in more ways than you think. Join me as we explore what it means that our universe is expanding.
So I think it would be a safe bet that between various TV shows, movies, and potential our channel right here that you would have heard that the universe is still expanding despite it being billions of years old. BUT, if you haven't...then we'll explain a little of the basics of what this means.
You see, for a long time, the universe was believed to be finite. Quite literally. Not unlike how many people thought the Earth was flat and that going to the edge of it would have you "fall off" into oblivion, the same thoughts were put on to those about the universe as a whole. That there was somewhere out there a finite line where our universe just...stopped.
So what exactly happened to make people believe that this wasn't the case? A lot of things actually, but at its core, it's about some people realizing that things were moving up there beyond what is the norm. One of the first people to realize this was the legendary astronomer Edwin Hubble, who in 1922 realized that not only is the universe expanding, it's expanding AWAY from Earth, including whole galaxies moving at a rate that shouldn't technically be possible, but is so for various things. Such as massive galaxies.
But then a thought came into the minds of scientists, if something is moving away at a certain rate and speed, wouldn't it also mean that they are moving away from an origin point? Meaning that something got them started on their cosmic dash across their stars. This was one of the first times the idea of a "Big Bang" came to be. And it would help give a lot of answers, but also raise a lot of questions.
For those that don't know, the Big Bang Theory (the scientific principle not the TV show...come on now...) is the belief that there was an incredible of energy that came forth out of nowhere (or seemingly nowhere) in the universe, and from that the , everything was formed over time.
You see, most scientists agree that after everything 'settled down' from the massive that created it that things began to grow, expand, evolve, and of course, change. For example, it may seem logical to an extent that the growth of Earth came rather quickly, but that's not the case. Earth took billions of years according to scientists to get just the most basic of life made, and then it took billions of years more to get to where we are now.
The same goes for the rest of the universe. Because while it may seem easy to think that everything just "settled down" after the big that created everything, that's not likely. The edge of the universe likely shifted quite a bit before "settling down", if it ever settled down at all given that the universe could be theoretically infinite, and is almost proven to be infinite as we're discussing now.
That's one of the big reasons that scientists try and not just prove the Big Bang, but try and get a lot of information from its potential origin, because it could prove why the universe is like it is, and why it's expanding like it is.
Why do I say that? Well...think of the Big Bang like...a bag of marbles. Trust me, this will make sense. So the beginnings of the Big Bang, before the is like the bag of marbles. Everything is compacted, stacked on top of one another, and on and on. Then, the Big Bang itself is you releasing the marbles onto the hardwood floor of your house. It's loud, it's powerful, and it goes EVERYWHERE. And depending on the size of your floor, it could go on quite a ways. But eventually, it'll stop, right? It's going to lose momentum and wind up in a certain spot, momentum dies down over time no matter how fast you're going.
And it's there that a lot of people have questions about what is going on in the universe. Because if the universe is really billions of years old, and we can see the various galaxies and stars and such are in a certain spot or orbit, even with the movement that Hubble observed, how is the universe still expanding?
It didn't make sense that something was growing when there should've been no residual parts of the Big Bang to push it forward. So what was going on here? The answer that was found (in theory at least) was that of the concept of Dark Energy and Dark Matter.
Scientists believe that Dark Matter is the reason that galaxies exist as we know them. How does that work when the Big Bang apparently created everything? Simple, while the Big Bang was the "creation" event, many scientists have noted that galaxies shouldn't stay together in their current forms. Meaning, they shouldn't rotate in place. Instead, they should just fly apart.
But instead, they stay close (most of the times anyway, there are exceptions to the rule) and become "formed" objects in space. The reason for this is that Dark Matter has gravity..