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What did you learn today?

So I was bored at work during some downtime yesterday, and I'm kinda enthusiastic about astronomy and cosmology, so I did some surfing around on the internet to see what I could read about, and learned that there is a limit to the size of structures in the universe, and that while, for all we know, the universe does go on "forever", the things/groupings of things within it only get so big.

So we've got galaxies, right? We're all familiar with them. Usually, that's the biggest "thing" that people assume there is in the universe. Well, those conglomerate into galaxy clusters, which can then turn into even huger masses of galaxies that form strings, filaments, and literal walls of galaxies. Well, when you keep "zooming out", you end up with an impossibly huge network of galaxy strings, walls, and giant voids in between these structures (voids in the diameter range of many millions of light years). This is considered one, single structure, called the Cosmic Web, and it literally looks just like a spider web, except spanning the entire visible universe. Here's a snippet of a simulation of the data that we've collected on it, so that you can get a better idea of what this looks like.

AstroMSseqF_063aL_18135101.jpg


A parsec is equal to about 3.26 light years (31 trillion kilometers or 19 trillion miles). A megaparsec (the unit of measurement used in the above image) is 1 million parsecs. Each of those tiny, individual dots is a representation of an entire galaxy, most containing millions to trillions of stars in their own rights. The purple framework is the dark matter that all of the universe hangs on, like a lattice.

Now here's the above image, in full.

cosmic_web_3smaller.jpg


Kind of mind blowing, right? The scale is just totally incomprehensible. And that's just a representation of a single section of the OBSERVABLE universe. Since the universe has only been around for 13 billion years and change, we can only see out to a certain distance, since light has only had those 13ish billion years to travel, meaning that it could keep going on and on, way outside of our visual, time-constrained range.

If you were to keep zooming out of the above image, you'd find that there are no larger structures to be had. The universe becomes a mostly uniform wash of galactic webs and voids. This phenomena is known as the End of Greatness, since there's seemingly nothing more to the universe's structure at these large scales, at least as understood by our current models.

Sorry for the wall o' text, this was just something that I had found incredible fascinating, and thought you here might as well. Isn't science grand? :woot:
 
Isn't the uniform wash of galactic webs in itself a larger structure?

Astrophysics is pretty difficult to understand, especially the instantaneous appearance of the universe, visible or otherwise. How does something that seemingly has no bounds expand?

But Astrophysics has nothing on quantum mechanics. That's just inexplicably odd.
 
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So I was bored at work during some downtime yesterday, and I'm kinda enthusiastic about astronomy and cosmology, so I did some surfing around on the internet to see what I could read about, and learned that there is a limit to the size of structures in the universe, and that while, for all we know, the universe does go on "forever", the things/groupings of things within it only get so big.

So we've got galaxies, right? We're all familiar with them. Usually, that's the biggest "thing" that people assume there is in the universe. Well, those conglomerate into galaxy clusters, which can then turn into even huger masses of galaxies that form strings, filaments, and literal walls of galaxies. Well, when you keep "zooming out", you end up with an impossibly huge network of galaxy strings, walls, and giant voids in between these structures (voids in the diameter range of many millions of light years). This is considered one, single structure, called the Cosmic Web, and it literally looks just like a spider web, except spanning the entire visible universe. Here's a snippet of a simulation of the data that we've collected on it, so that you can get a better idea of what this looks like.

AstroMSseqF_063aL_18135101.jpg


A parsec is equal to about 3.26 light years (31 trillion kilometers or 19 trillion miles). A megaparsec (the unit of measurement used in the above image) is 1 million parsecs. Each of those tiny, individual dots is a representation of an entire galaxy, most containing millions to trillions of stars in their own rights. The purple framework is the dark matter that all of the universe hangs on, like a lattice.

Now here's the above image, in full.

cosmic_web_3smaller.jpg


Kind of mind blowing, right? The scale is just totally incomprehensible. And that's just a representation of a single section of the OBSERVABLE universe. Since the universe has only been around for 13 billion years and change, we can only see out to a certain distance, since light has only had those 13ish billion years to travel, meaning that it could keep going on and on, way outside of our visual, time-constrained range.

If you were to keep zooming out of the above image, you'd find that there are no larger structures to be had. The universe becomes a mostly uniform wash of galactic webs and voids. This phenomena is known as the End of Greatness, since there's seemingly nothing more to the universe's structure at these large scales, at least as understood by our current models.

Sorry for the wall o' text, this was just something that I had found incredible fascinating, and thought you here might as well. Isn't science grand? :woot:


I'd love to explore all that, but I get the feeling I'd better use the john before we leave.
 
Isn't the uniform wash of galactic webs in itself a larger structure?

Astrophysics is pretty difficult to understand, especially the instantaneous appearance of the universe, visible or otherwise. How does something that seemingly has no bounds expand?

But Astrophysics has nothing on quantum mechanics. That's just inexplicably odd.

To my understanding, it's still just the Cosmic Web. Even though as we zoom further and further out it gets more and more uniform, it doesn't itself form something larger.

Yeah, the beginning/ending of the universe theories are kinda hard to grasp. The best analogy i can think of for expansion is a loaf of raisin bread. Think of it like this - when you make the dough, the raisins are suspended within it. As it bakes, the dough expands, causing the raisins to move away from each other proportionally, which is what it looks like in our universe. When we look out at damn near anything beyond our galaxy, we see that it's moving away from us and everything else, equally.
 
To my understanding, it's still just the Cosmic Web. Even though as we zoom further and further out it gets more and more uniform, it doesn't itself form something larger.

Yeah, the beginning/ending of the universe theories are kinda hard to grasp. The best analogy i can think of for expansion is a loaf of raisin bread. Think of it like this - when you make the dough, the raisins are suspended within it. As it bakes, the dough expands, causing the raisins to move away from each other proportionally, which is what it looks like in our universe. When we look out at damn near anything beyond our galaxy, we see that it's moving away from us and everything else, equally.
Sure, but my loaf of raisin bread has a center and an outer boundary. My universe, not so much.
 
I've learnt this:

Back story - the only time a birthday ever bothered me was when I turned forty. Don't know why. 20, 25, 30, 35, nothing. 40, my life was over. I never accomplished any of my goals in life. Sure, I had a good job, a good home, a good wife, I lived in a great city, state, country, continent... I was (and continue to) live the life of a top one percenter in the universe, but turning forty was death. 45, 50, 55, nothing.

Cut to today - I turned 59 last month... I wish I was 60. I just want to get it over with.
 
I am 57 years old and no that is not what I learn today. What I did learn was something that was never taught in NJ school system. That NJ from 1914-1917 was attacked by terror cells before the war. Supposedly no actual proof but historians believe it to be true
I like many thought that the 911 attack was the only time anyone attacked us at home.

Henry Landau, a captain in the British Secret Service, published a book called "The Enemy Within" in 1937. In it he claims a spy network began its two-year reign of terror with attacks on NJ
 
7464140-4x3-700x525.jpg

Black Kites chase insects during a bushfire at Kakadu National Park (Auscape / Getty Images)
I learns there's a hunt underway for Gondwanaland's mythical "Bushfire Birds". These wiley raptors could show us a thing or two about barbecue.

They're experts. And we're out to prove it. :cool:
You should check out the series Planet earth: Africa. It's really interesting and they cover the stuff that you posted too.
 
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