PublicAnimalNo9 wrote:
andyt wrote:
I thought it was infinite?
Nope.
Well, technically, no one knows if the universe is infinitely large or not. As the video said, we also don't know if we're the only universe spiraling through the void, either, or if we're one of many universes expanding. As the video notes, there are differences between how the universe behaves locally, and how in behaves farther away. It does not delve into into a lot of other little quirks in our little pocket of space-time which complicate our understanding and perception of what is contained within it.
I appreciated that they brought up chaotic inflation theory within the video. It's an incredibly interesting theory which is a subset under the eternal inflation theory. It was exciting to see this brought up, since more often than not you hear about the Heat Death of the universe or the Big Crunch before any of the other stuff which was mentioned in this video are even mentioned. I guess it's just not depressing enough for people at large.
Here's a link for people interested in that topic. What's even more fun is that we can't even be sure about the shape of the universe -- in the last decade alone, suggestions of alternative shapes have risen to contradict and challenge ongoing perceptions of how the universe is structured.
I also loved that they brought up Dark Matter, but I wish they had gone into more detail. Dark Matter is suggested to take up perhaps 80% of all matter in the universe, while conventional matter, or matter we recognize, takes up only 20%. That means that those elements on our table only make up 20% of what we are looking at in space. The rest we can only infer. Only a little of this dark matter may be from MACHO, which are constructed of conventionally recognized matter. What's even more interesting is that only about 4-5% of mass energy in the universe can be attributed to matter we recognize, with the rest going to that Dark Matter.
Dark Energy is even more interesting than that, since it's toying with some of the foundations of the universe as we understand it! For example, it's estimated that the acceleration of the growth of the universe only began 5 billion years ago. Before that, growth was slowing. A lot of the most basic theories are affected by dark energy and ongoing study of dark energy has brought up even more questions. It's all quite exciting. To me, anyways.
The fun, final bit is because of the speed of light, even though the universe can expand a lot faster than it, we cannot actually perceive those changes because of how long it takes for light to reach us. Our measurements are constantly restricted because of the speed of light, and the fact that it is a constant. It's fun thinking of all those mysteries which are just beyond that limited range of sight!
I've got to go dork out over something else now. Hopefully I didn't make any errors in my above post!
CKA Moderator 
Or was that just the road I live on? ![[huh]](./images/smilies/icon_scratch.gif "huh?"){kind=icon}
