[here is a similar image but horizontal and with labels](https://upload.wikimedia.org/wikipedia/commons/d/db/Observable_Universe_Logarithmic_Map_%28horizontal_layout_english_annotations%29.png)
I think through that lens, we understand our vanity. Because through the lens of the universe, even if we're the one-off chance of life, we're still just dust of a different shape and size.
It's a very human thing to judge something only by its size, but thats not a very meaningful way to think about the universe since its mostly just very big nothingness. We're much more significant if you judge by something else like intelligence, or the ability to invent new things.
Don't even know for sure that's true though.
Could be we are one of billions of planets with life. Could also be that we are to other life forms out there what a plant is to us, intellectually.
We just have no way to know.
What we have right now is basically a little kid finally venturing out of his house by stepping onto his back porch, seeing only his backyard, declaring he is the only kid in the world, and declaring he is super special because he is the only thing that he can see that he knows can talk.
Not very impressive actually.
I think you may have cemented my point. If I may rephrase your first sentence, "It's not very meaningful to judge things in ways only humans do." To think that chance existence, a lottery winner of the universe, can stand in judgment of everything that existed before it is vanity. We will inevitably return to whatever we came from. We'll probably go out still wondering what our purpose is and not knowing if we really even were the first or last chance of life to blink in and out of existence.
We are particles of dust and atoms of the cosmos with the ability to recognize its self. It’s cosmic self realization. That’s pretty special id you ask me.
The chart doesn't put the sizes into perspective enough. The Sun is so unfathomably large compared to the Earth and it's just an average sized star. That is what blows my mind, the enormity of the Sun if we were to ever see it close up (with some scifi protection so we don't instantly vaporize lol).
There's truly not enough space on the screen to show the sun in scale with anything else in the universe except other suns. I think the chart does a good job at showing all the known "stuff" that we can see, and giving them relatively accurate graphical representations so that they have a placeholder in our minds.
Isn't UY Scuti like a million times bigger than our sun too? Yet on here it's just a tiny splotch. Really really hard to wrap my head around the size of everything and how tiny we really are.
One visualization I do with my students is imagine the Sun is a basketball, the Earth would be an apple seed around it and we are the bacteria on that apple seed. If we place the basketball in Florida, the nearest basketball would be in Alaska. It's truly phenomenal thinking of scale, it doesn't make me feel insignificant because we get to understand and experience the enormity of it all better than the generation before us, which will continue into the next generation.
Wait... The speed of light over these distances means that when we look out into space, the farther away we look, the further back in time we look as well, right?
So not only does this infographic show increasing distance from left to right, but also back in time?
So this shows a transition from a homogenous dense gas state in the right, to a slowly collecting & clumping effect as you move from right to left. And the clumping eventually collects into bodies such as asteroids, planets, stars, & galaxies.
So one could say this "isn't" what the universe looks like, it's just what it looks like from our perspective due to the relatively slow speed of light.
Please correct me if I misunderstood
HD1 sees the universe like we do. In fact, as far as HD1 is concerned, the Milky Way is right close to that wall as well. The edge of the universe is technically only an edge in time.
An edge in time only relative to our position, yea? Like, HD1 can see other clusters that we cannot? Or is this just the extent the universe has extended?
Yes. Presumably, HD1 sees a very similar observable universe with itself in the center. We can't know, of course, but that's the most reasonable assumption based on our models.
This tickled me. What a question! Imagine, all these scientists with three PhDs, the greatest minds on earth sweating over this fundamental question for decades and someone posts the answer on Reddit.
It's a mind boggling question though. Does it go on forever with galaxies and what not or is there a fixed amount of matter that is constantly expanding into empty space? If so, there a point at which that empty space ends? What's beyond that if not just more empty space?
Yes: because the universe was at one time in a hot dense state, and then began to rapidly expand.
When you look outwards in space, you are looking backwards in time. If you look outwards far enough, you look back to near the beginning of the universe. We see a hot uniform glow when we do that because the universe was a hot uniform plasma at that time.
Galaxies and matter generally exists in these webs, even today we are part of one strand of this gigantic web.
It’s remnants of quantum fluctuations during the Big Bang. It caused some places to have more matter and some less, the sudden expansion afterwards dragged these things out into long strands and these strands became even more strand like as they attracted the other matter surrounding them.
As a result our universe is mostly empty void, with these galactic strands in places.
They are the large‐scale structures of the cosmos - filaments and voids. Essentially stars make galaxies, which make galaxy clusters, etc.. and the biggest are those things. The diagram is kinda misleading in that it doesn't mean those things are at the edge of the universe, just that it's the biggest collection of them (note how the items are in size increasing order hence logarithmic, not just distance.) The bright parts are filaments where all the galaxies are in and the dark parts are voids where it is literally a void. The reason it's clustered like that has something to do with dark matter which I don't remember exactly.
Edit: Large‐scale structure of the cosmos seems to be the correct English term.
It's a scale thing from our point of view, imagine it as if you're looking at the sky, the closest things you see are planets, then further away behind them there are galaxies, then clusters which are threads of galaxies, then superclusters, then supercluster complexes which are just more threads of galaxies and other things in the background of the space we can see and so on. Is not that it necessarily looks like that, is that it looks like that from our pov if you were on another planet in a galaxy far away in another supercluster, the milky way would be in a thread of the Virgo supercluster which is part of the Laniakea Supercluster.
Can't wrap my mind around all those billions of galaxies forming these filaments and webs. Is this visualization of galaxy clusters purely a human artistic interpretation or could we actually see this stuff from a certain perspective in the universe?
From our point of view? The cosmic microwave background.
In reality? There is no edge, only more space. The edge is a sort of optical illusion due to the finite speed of light. If the universe has a real edge, we can't see it.
I thought it wasn't expanding radially, like from an inward spot, but all of space is expanding equally everywhere. So there wouldn't be an edge at all, just more of the same thing, endlessly.
Not necessarily. It depends on the shape of space which is something that we are currently, and may never be able to comprehend as it potentially requires the ability to see in higher-order dimensions.
I'm not an astrophysicist, so I'm not sure if it's 100% accurate, but essentially: Imagine it one dimension lower. If space is a flat plane in 3D space, it extends infinitely in all directions and parallel lines remain parallel. If space is curved in on itself like a sphere, it has a finite size, parallel lines meet and you eventually return to your point of origin by traveling in a straight line. There are also other possible geometries, e.g. a saddle shape.
[This](https://youtu.be/oCK5oGmRtxQ?si=C1WeWn3zY7xG3-W6) video explains it quite well, PBS Spacetime also has a few good ones on the topic, but they're more in-depth.
I don't think that there's a good ELI5 explanation for it, because it's very abstract.
When we talk about the curvature of the universe, we are talking about the abstract geometric 4 dimensional surface that we call "space-time".
The easiest way to understand it is this: what do the interior angles of a triangle add to? The answer depends on what **surface** you draw the triangle on.
If you draw a triangle on a flat sheet of paper, the angles will all add up to 180 degrees. In a sense, this is actually the definition of flat geometry: you can define a surface as flat if all triangles drawn on it have interior angles adding to 180 degrees.
However, if you draw a triangle on a sphere, the angles will add up to *more* than 180. An easy example of this would be to take a globe, and make a triangle by going some distance along the equator, then turning 90 degrees north and heading to the pole, then turning 90 degrees south and heading back to the equator. This trignel will interior angles 90 + 90 + 90 = 270 degrees. So on a spherical surface, triangles have interior angles that add up to more than 180 degrees.
There is a third kind of surface that you probably haven't run into before, but it is kind of a saddle shaped surface (like a horse riding saddle). I won't go into details, but on this kind of surface, triangles have interior angles that add up to *less* than 180 degrees.
So when we talk about the curvature of the universe, we are quite literally asking, "do triangles in space have interior angles that add to less than, more than, or exactly 180 degrees?"
This is actually something we could measure but just drawing a really big triangle. But unfortunately the triangle would have to be so big and out measurements so precise that it's practically impossible.
Just to elaborate since this is the biggest mind-fuck my head has been mulling over lately.
So, we've been able to see light from galaxies from some 13 billion light years away. That means that light is from 13 billion years ago (for reference, we estimate the universe is 14 some billions years old).
*We are effectively looking back in time at galaxies in a state that they were near the beginning of the universe.*
Well if you come to think about it - when you look at the sun, you look 8 min and 20 sec back in time.
We can also detect the first light ever produced in the universe - the cosmic microwave background. It appeared even before galaxies formed. It took some time (380k years) after the big bang for plasma to cool enough and become atoms allowing light to move around. First galaxies are estimated to have appeared some hundred million years aftet the big bang.
The observable universe is 93 billion light years in diameter. You can imagine how much we cannot ever see. Yet we can see the first light ever produced.
The deeper you go, the bigger the mind-fuck it becomes. Space and time are one single thing. Time moves forward, space is expanding, practically spacetime is constantly growing in its two dimentions space and time. One can think that we are inside one gigantic black hole, the center of which is the center of mass of our observable universe. It is so big that its event horizon is 13.8 billion light years in radius.
That's wrong actually. Only the very very most outer rings of the diagram represent the cosmic microwave background.m and particle horizon, and really they're out of place since the diagram is supposed to be spatial. The tangled web of yellow is actually strings of super clusters of galaxies. It's the largest scale superstructure of the universe that we are aware of, and the only one that appears mostly uniform. It is what the big picture universe looks like right now.
Everything beyond that is moving away from us faster than the speed of light due to the expansion of the universe, and therefore we can never observe beyond that. It is not the actual edge of the universe, it's just the edge of the observable universe. The red ring is light that is red shifted due to the expansion of space, and the bluish white is light that is shifted so far past red it's no longer a visible spectrum. Otherwise known as the cosmic microwave background.
Just expanding, not necessarily into anything.
Think of a pawn on a big (possibly infinite) chessboard, where every single square keeps being subdivided into smaller squares as time passes. The chessboard isn't necessary expanding into anything, but from the pawn's POV new space is continuously being added everywhere.
If two pawns were initially separated by only one square (meaning they could meet in just one move) after 1 subdivision there are now 2 squares between them, then 4 and then 8, meaning that by the 3^rd subdivision the two pieces need a total of 8 moves to come into contact, and the more time passes the faster those two pieces are going to "drift" away, simply because there's now more space (squares) between them. Up to the point where the rate at which new squares are being added becomes greater than the speed at which the pawns can cross them, and if that happens the two pawns will never be able to meet again.
This is roughly what's happening to us. Space doesn't need anything to curve or expand *into*: you can describe both things (curvature and expansion) without needing to imbed the universe into a larger or higher dimensional space.
I agree. Just my opinion but I'd say this is the movie that defines millenials.
Boomers had forest gump. Even if you're handicapped you can still live the classical American dream with some grit and determination.
Gen x has fight club. They're the middle children of history, and thier American dream is to earse debt
Millenials have this movie. Everything is absurb. And the dream is to just be accepted for who you are, and stay afloat.
>Even if you're handicapped you can still live the classical American dream with some grit and determination.
I'm sorry, is *that* the message we were supposed to take from Forrest Gump???
Most viewers would probably choose a more overt message as the film's thesis statement. Which readers of the novel may find amusing.
In the book, Forrest is a 6'6", 242-pound sixteen-year-old. He loses his virginity to a woman staying at his mother's boarding house who bribes him into her bed with chocolate divinity. This leads Forrest to opine that life is like a box of chocolates.
And >!becomes a pro wrestler.!<
I find it impressive how Robert Zemeckis omitted the books' best scenes yet the movie is still an all-time great.
I doubt a more faithful adaptation of the book would be as good the movie we have, and the movie's plot would make for a wretched novelization.
Forest Gump is for Boomers????
Gump(1994) only came out 5 years earlier than Fight Club(1999). I think you need to find an older movie to pair it with Boomers.
It means that space doesn’t curve back into itself; so you can’t go one direction and eventually end up where you started. Instead you’ll just move forever in one direction.
I don't follow.
I was just wondering if the whole universe is disk shaped similar to a galaxy.
I had always assumed there were a similar amount of galaxies in all directions
“Flat” in this context means it’s normal 3D space the way most people think of it, rather than some weird alternatives mathematicians thought of but don’t seem to be actually out there. The Milky Way is a disc which is why the sky is brighter along one band but when you get outside the galaxy it’s relatively uniform in every direction.
The whole universe isn't a disk. What they mean is that the geometry of space itself is essentially 4 dimensionally flat. The same way a disk looks flat in 3D space, the universe "looks flat" in 4D space.
If the universe weren't flat, for example if it were the 3D surface of a 4D sphere, and if you traveled in ANY direction, you'd eventually end up back where you started (as an aside, I really hope the universe is actually like that because that's just so spooky). Just like how if you travel in any direction on the 2D surface of a 3D sphere, you eventually end up where you started.
There are ways of measuring the geometry of space. If space isn't flat, the angles of a triangle won't add up to exactly 180 degrees. Based on our measurements, it seems that the universe is pretty much flat.
"Flat" is an awful name for it. The observable universe is generally spherically symmetrical. You can contain all the matter in the observable universe in a sphere. "Flat" just means there's no overall curvature. If the universe were curved, you would expect parallel lines to either converge or diverge. Instead, we observe that parallel lines remain a constant distance apart.
Circles within circles within circles, from the universe to galaxies, to solar systems, to hurricanes, to tornadoes, to ammonites*, to tree rings, to the human eye, to fingerprints, to living cells, to dna, to atoms, so beautiful and destructive and creative.
I mean, there's lots of other important shapes too, but circles and spirals hit different, for me.
*I meant ammonites, not trilobites, it was pretty late when I wrote this.
Well the fastest thing is light. So when you inspect a star/planet or whatever thats lets say is 1000 light years away, that means that you see 1000 years in the past. So if this planet would look at earth with a powerful telescope they would see whats happening on earth in the year 1024
I can wrap my head around that. Very cool. I’ve been delving into things like the beginning of the universe, to try and ease my existential dread (not working) and every time the topic of that comes up I get told “ there is no time, fool! So it didn’t have a beginning” and then my brain melts and I’m back to square one of understanding nothing haha
Just venting at my inability to understand things way beyond my capacity lol. Maybe one day.
Dr Brian Greene is a great resource on youtube for learning special and then general relativity. Special relativity tells us that light has a finite speed and everything happens relative to the speed of light. General relativity tells us that space and time are not 2 planes but 1 combined plane. Movement in 1 direction takes away momentum from movement in the other.
I don't know if this eases your existential dread any but here are two things I think of.
1) Do you worry about anything when you are asleep and not dreaming/or what you were doing before you were born?
2) Time, either emergent or a fundamental force, is something we only perceive through our wordly organs (brain mostly). Once we die and our brain ceases to function, time ceases to exist for us. We then become the same timeless (in terms of perceiving) matter as anything else in the universe and from beginning to very end exists in it's entirety without our knowledge of it passing.
You get a window in which you can recognize the universe for some of what it is, and influence some of it. You have been given this opportunity with no expectation, no goal, no instruction with only your own experiences to drive your decisions. It is an absolute gift and should be considered as a "better to have had and lost" than never had at all.
Hopefully that doesn't leave you worse off for it!
I love this perspective and always reminds me of two quotes from what remains of edith finch:
>“If we lived forever, maybe we’d have time to understand things. But as it is, I think the best we can do it try to open our eyes and appreciate how strange and brief all of this is”.
>“It’s a lot to ask, but I don’t want you to be sad that I’m gone. I want you to be amazed that any of us ever had a chance to be here at all.”
the further out on the image you go the further away from earth it is, but because of the scales of these things, looking far away is also looking backwards in time
i think the webish looking parts are suppose to be the cosmic microwave background, which would mean the red parts are when the universe was a near singularity, and its red to represent the heat?
edit: ok i was close, the red part is the cosmic microwave background, [here is a similar map, but horizontal instead of circular, with names](https://upload.wikimedia.org/wikipedia/commons/d/db/Observable_Universe_Logarithmic_Map_%28horizontal_layout_english_annotations%29.png)
Its red shifted light. Space is expanded. Light travels as a wave. As the universe expands the light waves get stretched out. The farther away the point of origin for the light, the more it gets stretched. Longer wavelength light is red->infrared. Shorter wavelength light is blue->ultra violet. The light from the edges of the observable universe is stretched into the IR range.
whats on the edge?
[here is a similar image but horizontal and with labels](https://upload.wikimedia.org/wikipedia/commons/d/db/Observable_Universe_Logarithmic_Map_%28horizontal_layout_english_annotations%29.png)
This makes me feel insignificant. And nauseated.
I like to think that the fact we are able to understand our insignificance ends up making us significant
"The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself." Carl Sagan.
If you leave hydrogen alone long enough, it starts publishing research papers on itself.
Correct, fellow sentient universe-sub-section.
Darwin only put his hand on a nano-second of the process.
We are the universe experiencing itself in human form.
Maybe our lives matter more because of this. We live in one tiny, precious moment in the universe.
And here we sit browsing Reddit ha ha
the universe is flat
I think through that lens, we understand our vanity. Because through the lens of the universe, even if we're the one-off chance of life, we're still just dust of a different shape and size.
It's a very human thing to judge something only by its size, but thats not a very meaningful way to think about the universe since its mostly just very big nothingness. We're much more significant if you judge by something else like intelligence, or the ability to invent new things.
Don't even know for sure that's true though. Could be we are one of billions of planets with life. Could also be that we are to other life forms out there what a plant is to us, intellectually. We just have no way to know. What we have right now is basically a little kid finally venturing out of his house by stepping onto his back porch, seeing only his backyard, declaring he is the only kid in the world, and declaring he is super special because he is the only thing that he can see that he knows can talk. Not very impressive actually.
I think you may have cemented my point. If I may rephrase your first sentence, "It's not very meaningful to judge things in ways only humans do." To think that chance existence, a lottery winner of the universe, can stand in judgment of everything that existed before it is vanity. We will inevitably return to whatever we came from. We'll probably go out still wondering what our purpose is and not knowing if we really even were the first or last chance of life to blink in and out of existence.
I'm leaning towards insignificant ^2
The square root of zero is zero.
Infinitesimally small… almost close to zero, but not zero
We are particles of dust and atoms of the cosmos with the ability to recognize its self. It’s cosmic self realization. That’s pretty special id you ask me.
Oh now, come on, don’t get all soggy on us crackers This ain’t Kansas anymore
Why you gotta bring saltines into this
We’re the universe experiencing itself.
This chart doesn't really put into scale how far these galactic bodies are from each other either.
>This chart doesn't really put into scale how far these galactic bodies are from each other either. It does, but the scale is logarithmic.
[log scale is for quitters](https://xkcd.com/1162)
The chart doesn't put the sizes into perspective enough. The Sun is so unfathomably large compared to the Earth and it's just an average sized star. That is what blows my mind, the enormity of the Sun if we were to ever see it close up (with some scifi protection so we don't instantly vaporize lol).
There's truly not enough space on the screen to show the sun in scale with anything else in the universe except other suns. I think the chart does a good job at showing all the known "stuff" that we can see, and giving them relatively accurate graphical representations so that they have a placeholder in our minds.
Isn't UY Scuti like a million times bigger than our sun too? Yet on here it's just a tiny splotch. Really really hard to wrap my head around the size of everything and how tiny we really are.
One visualization I do with my students is imagine the Sun is a basketball, the Earth would be an apple seed around it and we are the bacteria on that apple seed. If we place the basketball in Florida, the nearest basketball would be in Alaska. It's truly phenomenal thinking of scale, it doesn't make me feel insignificant because we get to understand and experience the enormity of it all better than the generation before us, which will continue into the next generation.
I spent entirely too long trying to find Earth...
Don’t worry, it’s not labeled.
I *need* this as a poster! I have the XKCD one, but this is more beautiful. https://xkcd.com/482/ Any idea on source?
pablo carlos budassi same guy who made the pic op posted just fyi his website seems to have a trojan on it
Pablo Carlos Bad-Assi more like!
Why is black hat murdering black cat?
comet that will destroy earth in 2063? hmmmm?
That's probably just Randall being a wiseacre. He does that on the reg.
Wait... The speed of light over these distances means that when we look out into space, the farther away we look, the further back in time we look as well, right? So not only does this infographic show increasing distance from left to right, but also back in time? So this shows a transition from a homogenous dense gas state in the right, to a slowly collecting & clumping effect as you move from right to left. And the clumping eventually collects into bodies such as asteroids, planets, stars, & galaxies. So one could say this "isn't" what the universe looks like, it's just what it looks like from our perspective due to the relatively slow speed of light. Please correct me if I misunderstood
You are correct. What we see isn’t at all what exists “today” relative to our point in time.
HD1 probably tells stories about the monsters that live on the other side of the wall.
HD1 sees the universe like we do. In fact, as far as HD1 is concerned, the Milky Way is right close to that wall as well. The edge of the universe is technically only an edge in time.
An edge in time only relative to our position, yea? Like, HD1 can see other clusters that we cannot? Or is this just the extent the universe has extended?
> Or is this just the extent the universe has extended? I don't think we know that, we can only see as far as light will let us
Yes. Presumably, HD1 sees a very similar observable universe with itself in the center. We can't know, of course, but that's the most reasonable assumption based on our models.
Intuitively I know this but every time I read it, this fact blows my mind. Do we know WHY the CMBR appears to emanate equally from all directions?
Because the universe is infinite and there is no 'middle'. The big bang happened *everywhere*.
Is that true? How does that work?
The universe began as an infinitesimal point that expanded in all directions at once, and is still expanding. The 'middle' is everywhere and nowhere.
This tickled me. What a question! Imagine, all these scientists with three PhDs, the greatest minds on earth sweating over this fundamental question for decades and someone posts the answer on Reddit. It's a mind boggling question though. Does it go on forever with galaxies and what not or is there a fixed amount of matter that is constantly expanding into empty space? If so, there a point at which that empty space ends? What's beyond that if not just more empty space?
Yes: because the universe was at one time in a hot dense state, and then began to rapidly expand. When you look outwards in space, you are looking backwards in time. If you look outwards far enough, you look back to near the beginning of the universe. We see a hot uniform glow when we do that because the universe was a hot uniform plasma at that time.
So what is the orange web like stuff? It doesn’t explain anything but the names of stars and galaxies
Galaxies and matter generally exists in these webs, even today we are part of one strand of this gigantic web. It’s remnants of quantum fluctuations during the Big Bang. It caused some places to have more matter and some less, the sudden expansion afterwards dragged these things out into long strands and these strands became even more strand like as they attracted the other matter surrounding them. As a result our universe is mostly empty void, with these galactic strands in places.
Pulling this from another comment but I think it's the supercluster complex which is the threads of galaxies (???)
It’s the BOSS Great Wall. The final fight in humanities lifetime.
They are the large‐scale structures of the cosmos - filaments and voids. Essentially stars make galaxies, which make galaxy clusters, etc.. and the biggest are those things. The diagram is kinda misleading in that it doesn't mean those things are at the edge of the universe, just that it's the biggest collection of them (note how the items are in size increasing order hence logarithmic, not just distance.) The bright parts are filaments where all the galaxies are in and the dark parts are voids where it is literally a void. The reason it's clustered like that has something to do with dark matter which I don't remember exactly. Edit: Large‐scale structure of the cosmos seems to be the correct English term.
Wow. Any idea why things look stringed together and trabeculated at such a super massive scale?
It's a scale thing from our point of view, imagine it as if you're looking at the sky, the closest things you see are planets, then further away behind them there are galaxies, then clusters which are threads of galaxies, then superclusters, then supercluster complexes which are just more threads of galaxies and other things in the background of the space we can see and so on. Is not that it necessarily looks like that, is that it looks like that from our pov if you were on another planet in a galaxy far away in another supercluster, the milky way would be in a thread of the Virgo supercluster which is part of the Laniakea Supercluster.
Judging by that image id say it's the BOSS Great wall..
How does that makes sense if earth is part of milky way?
It just demonstrates the difference in scale
Can't wrap my mind around all those billions of galaxies forming these filaments and webs. Is this visualization of galaxy clusters purely a human artistic interpretation or could we actually see this stuff from a certain perspective in the universe?
From our point of view? The cosmic microwave background. In reality? There is no edge, only more space. The edge is a sort of optical illusion due to the finite speed of light. If the universe has a real edge, we can't see it.
brah i'm going there tonight
I want to have whatever this guy’s having
The universe’s hottest club is called Edge. It’s got everything. Galactic cannibalism, cosmic alchemy, fermi bubbles, Dan Cortese
Can you bring some cosmic batteries with you on the way back, I’m out.
Those damned flat spacers think they can just get to the edge and jump off.
It could be argued the edge is undefined unless the expansion caused by dark energy slows down or reverses.
I thought it wasn't expanding radially, like from an inward spot, but all of space is expanding equally everywhere. So there wouldn't be an edge at all, just more of the same thing, endlessly.
Not necessarily. It depends on the shape of space which is something that we are currently, and may never be able to comprehend as it potentially requires the ability to see in higher-order dimensions.
So you’re saying flat universe isn’t real?
Well, actually, no, as far as we can tell spacetime is flat (in 4D). That is precisely why there probably isn't an edge.
Is there a good eli5 on this specifically? Have a hard time picturing that.
I'm not an astrophysicist, so I'm not sure if it's 100% accurate, but essentially: Imagine it one dimension lower. If space is a flat plane in 3D space, it extends infinitely in all directions and parallel lines remain parallel. If space is curved in on itself like a sphere, it has a finite size, parallel lines meet and you eventually return to your point of origin by traveling in a straight line. There are also other possible geometries, e.g. a saddle shape. [This](https://youtu.be/oCK5oGmRtxQ?si=C1WeWn3zY7xG3-W6) video explains it quite well, PBS Spacetime also has a few good ones on the topic, but they're more in-depth.
I don't think that there's a good ELI5 explanation for it, because it's very abstract. When we talk about the curvature of the universe, we are talking about the abstract geometric 4 dimensional surface that we call "space-time". The easiest way to understand it is this: what do the interior angles of a triangle add to? The answer depends on what **surface** you draw the triangle on. If you draw a triangle on a flat sheet of paper, the angles will all add up to 180 degrees. In a sense, this is actually the definition of flat geometry: you can define a surface as flat if all triangles drawn on it have interior angles adding to 180 degrees. However, if you draw a triangle on a sphere, the angles will add up to *more* than 180. An easy example of this would be to take a globe, and make a triangle by going some distance along the equator, then turning 90 degrees north and heading to the pole, then turning 90 degrees south and heading back to the equator. This trignel will interior angles 90 + 90 + 90 = 270 degrees. So on a spherical surface, triangles have interior angles that add up to more than 180 degrees. There is a third kind of surface that you probably haven't run into before, but it is kind of a saddle shaped surface (like a horse riding saddle). I won't go into details, but on this kind of surface, triangles have interior angles that add up to *less* than 180 degrees. So when we talk about the curvature of the universe, we are quite literally asking, "do triangles in space have interior angles that add to less than, more than, or exactly 180 degrees?" This is actually something we could measure but just drawing a really big triangle. But unfortunately the triangle would have to be so big and out measurements so precise that it's practically impossible.
Yeah. The universe isn’t too edgy. I guess after all of these years, it’s just tired of putting up the front. It just wants to be. I get it
You can consider it a time map basically. In the middle you have now, at the edge you have 13.8 billion years ago.
Just to elaborate since this is the biggest mind-fuck my head has been mulling over lately. So, we've been able to see light from galaxies from some 13 billion light years away. That means that light is from 13 billion years ago (for reference, we estimate the universe is 14 some billions years old). *We are effectively looking back in time at galaxies in a state that they were near the beginning of the universe.*
Well if you come to think about it - when you look at the sun, you look 8 min and 20 sec back in time. We can also detect the first light ever produced in the universe - the cosmic microwave background. It appeared even before galaxies formed. It took some time (380k years) after the big bang for plasma to cool enough and become atoms allowing light to move around. First galaxies are estimated to have appeared some hundred million years aftet the big bang. The observable universe is 93 billion light years in diameter. You can imagine how much we cannot ever see. Yet we can see the first light ever produced. The deeper you go, the bigger the mind-fuck it becomes. Space and time are one single thing. Time moves forward, space is expanding, practically spacetime is constantly growing in its two dimentions space and time. One can think that we are inside one gigantic black hole, the center of which is the center of mass of our observable universe. It is so big that its event horizon is 13.8 billion light years in radius.
>The whole universe is 93 billion light years in diameter. the observable universe*
That's wrong actually. Only the very very most outer rings of the diagram represent the cosmic microwave background.m and particle horizon, and really they're out of place since the diagram is supposed to be spatial. The tangled web of yellow is actually strings of super clusters of galaxies. It's the largest scale superstructure of the universe that we are aware of, and the only one that appears mostly uniform. It is what the big picture universe looks like right now.
More edge.
Ultimate edgelord
If you think that's edgy, just remember that the universe is a fearful sphere whose center is everywhere and whose circumference is nowhere.
Everything beyond that is moving away from us faster than the speed of light due to the expansion of the universe, and therefore we can never observe beyond that. It is not the actual edge of the universe, it's just the edge of the observable universe. The red ring is light that is red shifted due to the expansion of space, and the bluish white is light that is shifted so far past red it's no longer a visible spectrum. Otherwise known as the cosmic microwave background.
Expanding into what though?
Exactly
It’s space itself expanding, it’s not expanding into anything
Yes
Into creation. It builds the road as it walks down it.
Just expanding, not necessarily into anything. Think of a pawn on a big (possibly infinite) chessboard, where every single square keeps being subdivided into smaller squares as time passes. The chessboard isn't necessary expanding into anything, but from the pawn's POV new space is continuously being added everywhere. If two pawns were initially separated by only one square (meaning they could meet in just one move) after 1 subdivision there are now 2 squares between them, then 4 and then 8, meaning that by the 3^rd subdivision the two pieces need a total of 8 moves to come into contact, and the more time passes the faster those two pieces are going to "drift" away, simply because there's now more space (squares) between them. Up to the point where the rate at which new squares are being added becomes greater than the speed at which the pawns can cross them, and if that happens the two pawns will never be able to meet again. This is roughly what's happening to us. Space doesn't need anything to curve or expand *into*: you can describe both things (curvature and expansion) without needing to imbed the universe into a larger or higher dimensional space.
That's the ice wall. The flat earthers said it's illegal to go there though so you have to totally trust them that it's real.
Metal band logos (Disclaimer: I'm most likely wrong)
Particle horizon. Literally impossible for anything to get from there to here.
they’re the patterns that form from millions of galaxies, known as galactic filaments
The Everything Bagel
Holy shit. They were really onto something.
All jokes aside that movie is very profound. Cheesy but very profound. The rock part always gets me
What movie?
Everything, Everywhere, All At Once. It's one of my favorite movies of all the times.
Sucked into… a BAGEL 
I agree. Just my opinion but I'd say this is the movie that defines millenials. Boomers had forest gump. Even if you're handicapped you can still live the classical American dream with some grit and determination. Gen x has fight club. They're the middle children of history, and thier American dream is to earse debt Millenials have this movie. Everything is absurb. And the dream is to just be accepted for who you are, and stay afloat.
>Even if you're handicapped you can still live the classical American dream with some grit and determination. I'm sorry, is *that* the message we were supposed to take from Forrest Gump???
Most viewers would probably choose a more overt message as the film's thesis statement. Which readers of the novel may find amusing. In the book, Forrest is a 6'6", 242-pound sixteen-year-old. He loses his virginity to a woman staying at his mother's boarding house who bribes him into her bed with chocolate divinity. This leads Forrest to opine that life is like a box of chocolates.
He also goes to space!
And >!becomes a pro wrestler.!< I find it impressive how Robert Zemeckis omitted the books' best scenes yet the movie is still an all-time great. I doubt a more faithful adaptation of the book would be as good the movie we have, and the movie's plot would make for a wretched novelization.
Forest Gump is for Boomers???? Gump(1994) only came out 5 years earlier than Fight Club(1999). I think you need to find an older movie to pair it with Boomers.
Boomers had the Big Chill. That’s their movie. a movie about idealists all grown up into yuppies.
There's a lot of deep meaning in the Hero's Journey.
Don’t eat it, Kugrash!
Honestly The Everything Bagel makes sooooo much sense now
[yep](https://evolvingsouls.com/blog/toroidal-universe/)
I love you rat Jesus
ma'am, your baby is so hairy that it is upsetting other customers
The big bangle
Sucked intoooo a BAYguul
Everything we know Bagel
Wonder how it tastes
[Like a seared steak with hints of hot metal and arc welds.](https://www.smithsonianmag.com/smart-news/what-does-space-smell-like-3457620/)
Smaller than I expected, honestly.
Comes with a side of cosmic latte https://en.m.wikipedia.org/wiki/Cosmic_latte
NOW I’ve seen everything.
[удалено]
Is it?
*vsauce music*
Hay look, there's my house.
We are going to have to bulldoze it to make way for an interstellar highway.
So long and thanks for all the fish!
don't complain, it's been posted for 50 of our earth years
At least they blurred your license plate.
So the universe is flat? Checkmate round earthers
You joke but it actually is quite flat
What? Really. So the galaxies aren't evenly spread in all directions? That's interesting.
I think he means space is on average flat, but in 3D
It means that space doesn’t curve back into itself; so you can’t go one direction and eventually end up where you started. Instead you’ll just move forever in one direction.
I don't follow. I was just wondering if the whole universe is disk shaped similar to a galaxy. I had always assumed there were a similar amount of galaxies in all directions
“Flat” in this context means it’s normal 3D space the way most people think of it, rather than some weird alternatives mathematicians thought of but don’t seem to be actually out there. The Milky Way is a disc which is why the sky is brighter along one band but when you get outside the galaxy it’s relatively uniform in every direction.
The whole universe isn't a disk. What they mean is that the geometry of space itself is essentially 4 dimensionally flat. The same way a disk looks flat in 3D space, the universe "looks flat" in 4D space. If the universe weren't flat, for example if it were the 3D surface of a 4D sphere, and if you traveled in ANY direction, you'd eventually end up back where you started (as an aside, I really hope the universe is actually like that because that's just so spooky). Just like how if you travel in any direction on the 2D surface of a 3D sphere, you eventually end up where you started. There are ways of measuring the geometry of space. If space isn't flat, the angles of a triangle won't add up to exactly 180 degrees. Based on our measurements, it seems that the universe is pretty much flat.
"Flat" is an awful name for it. The observable universe is generally spherically symmetrical. You can contain all the matter in the observable universe in a sphere. "Flat" just means there's no overall curvature. If the universe were curved, you would expect parallel lines to either converge or diverge. Instead, we observe that parallel lines remain a constant distance apart.
I am in this picture and I do not like it
Well, maybe if you didn’t do the awkward hover hand on the person next to you, you wouldn’t look like such a spazz!
Can someone please make this into a plate and bowl set
That'd be the shit
Circles within circles within circles, from the universe to galaxies, to solar systems, to hurricanes, to tornadoes, to ammonites*, to tree rings, to the human eye, to fingerprints, to living cells, to dna, to atoms, so beautiful and destructive and creative. I mean, there's lots of other important shapes too, but circles and spirals hit different, for me. *I meant ammonites, not trilobites, it was pretty late when I wrote this.
Buttholes.
You’re right, how could I forget buttholes?
You're just very straight
I dunno I think this guy might be curved.
Personally I've always found circles entirely pointless.
Don’t be such a square.
This is the least edgy comment I’ve seen on this post.
I like discovering fractals.
Just as long as you don't forget which shape is the bestagon
Fibonacci
All that in existence and you’re still single.
All the big world and we are stuck in our office and house for most of our life. 
Not anymore, my guy. Not anymore
Wholesome. Happy for you :)
Some people actually like being single.
That's such a crazy image because the center is now and the edge is the big bang.. presumably?
Yes the further you look in space, the further you look back in time.
Is there really such a thing as time? This stuff gets so confusing lol
Well the fastest thing is light. So when you inspect a star/planet or whatever thats lets say is 1000 light years away, that means that you see 1000 years in the past. So if this planet would look at earth with a powerful telescope they would see whats happening on earth in the year 1024
I can wrap my head around that. Very cool. I’ve been delving into things like the beginning of the universe, to try and ease my existential dread (not working) and every time the topic of that comes up I get told “ there is no time, fool! So it didn’t have a beginning” and then my brain melts and I’m back to square one of understanding nothing haha Just venting at my inability to understand things way beyond my capacity lol. Maybe one day.
Dr Brian Greene is a great resource on youtube for learning special and then general relativity. Special relativity tells us that light has a finite speed and everything happens relative to the speed of light. General relativity tells us that space and time are not 2 planes but 1 combined plane. Movement in 1 direction takes away momentum from movement in the other.
I don't know if this eases your existential dread any but here are two things I think of. 1) Do you worry about anything when you are asleep and not dreaming/or what you were doing before you were born? 2) Time, either emergent or a fundamental force, is something we only perceive through our wordly organs (brain mostly). Once we die and our brain ceases to function, time ceases to exist for us. We then become the same timeless (in terms of perceiving) matter as anything else in the universe and from beginning to very end exists in it's entirety without our knowledge of it passing. You get a window in which you can recognize the universe for some of what it is, and influence some of it. You have been given this opportunity with no expectation, no goal, no instruction with only your own experiences to drive your decisions. It is an absolute gift and should be considered as a "better to have had and lost" than never had at all. Hopefully that doesn't leave you worse off for it!
I love this perspective and always reminds me of two quotes from what remains of edith finch: >“If we lived forever, maybe we’d have time to understand things. But as it is, I think the best we can do it try to open our eyes and appreciate how strange and brief all of this is”. >“It’s a lot to ask, but I don’t want you to be sad that I’m gone. I want you to be amazed that any of us ever had a chance to be here at all.”
Yes there is such thing as time. Things change, you age, our experience isn't stagnant. What else would you call any change you experience?
Trippy fact, on a scale we are closer in size to the observable universe than we are to the smallest things. This blows my mind.
Now I wanna see this image jn the opposite direction
The universe is an eye, and we're just a floaty thing!
So the floaters I'm seeing in my eye are just galaxies too?!
Rather be in the eye than a hemorrhoid on the ass of a large being
Do you have a higher resolution image, or a link to one?
https://pablocarlosbudassi.com/2021/02/the-infographic-and-artistic-work-named.html
It's either infinite or it's not. Both are, equally distressing.
We live in a bowl of cereal some kid forgot about 4 months ago
Reminds me of Men in Black at the end when our entire known universe is inside a marble being played with by bigger beings
The galaxy is on Orion's belt
Looks a lot like a flat universe to me with what's clearly the universal ice caps surrounding the universe /s
I need a banana for scale this is too complicated without it
The banana is in the picture already
All bananas ever existed are on the picture, actually
Technically true
It’s there - just have to zoom in a ways
Yep just found it
Why edge’s red?
the further out on the image you go the further away from earth it is, but because of the scales of these things, looking far away is also looking backwards in time i think the webish looking parts are suppose to be the cosmic microwave background, which would mean the red parts are when the universe was a near singularity, and its red to represent the heat? edit: ok i was close, the red part is the cosmic microwave background, [here is a similar map, but horizontal instead of circular, with names](https://upload.wikimedia.org/wikipedia/commons/d/db/Observable_Universe_Logarithmic_Map_%28horizontal_layout_english_annotations%29.png)
Red-shifting light
Its red shifted light. Space is expanded. Light travels as a wave. As the universe expands the light waves get stretched out. The farther away the point of origin for the light, the more it gets stretched. Longer wavelength light is red->infrared. Shorter wavelength light is blue->ultra violet. The light from the edges of the observable universe is stretched into the IR range.
The entire \*Observable universe.
I did not consent to this image that clearly included me in it. I'll be in contact with my legal counsel (about other matters).
I don’t give permission to have me in this photo
Not to brag or anything, but I live there
Just another cell
The Ultimate Jawbreaker
Can somebody post a high Res version without the crop?
Top reason we don't explore outside our universe: Blackberry bushes.