A 1.3B-light-year-across ring of galaxies has confounded astronomers(cosmosmagazine.com)
cosmosmagazine.com
A 1.3B-light-year-across ring of galaxies has confounded astronomers
https://cosmosmagazine.com/space/astronomy/giant-structure-space-universe/
198 comments
That last video, at about 3:55, shows the ring as a bunch of red balls surrounded by a bunch of blue balls. All the balls seem randomly distributed, but a small subset are colored red. I wonder what makes those balls different? There doesn't seem to be anything unusual about their arrangement, other than they chose to color them red.
Interesting article. I'm not an astronomer, or any kind of scientist, but I tried perusing the paper anyway. What I expected to find was some indication that the stars in question are aligned on a plane - rather than being varying distances [1] from our pov and only looking like a ring to us. Is this information present and I missed it?
My other thought, with all respect to the expertise of the scientists involved, is that when we observe the universe at this massive scale it may be inevitable that structures will just appear out of the data, even with very high statistical significance. I don't know if this is a scientifically defensible position to take though.
Again - I'm not a scientist and I don't know what I'm talking about. Just musing, but interested in the opinions of others more informed than me.
[1] I'm aware that determining distance over cosmological distances is very difficult
My other thought, with all respect to the expertise of the scientists involved, is that when we observe the universe at this massive scale it may be inevitable that structures will just appear out of the data, even with very high statistical significance. I don't know if this is a scientifically defensible position to take though.
Again - I'm not a scientist and I don't know what I'm talking about. Just musing, but interested in the opinions of others more informed than me.
[1] I'm aware that determining distance over cosmological distances is very difficult
> stars
Galaxies. And determining the approx relative distance of distant galaxies is in fact easy thanks to cosmological redshift (the z values the article refers to). Anyway, given the number of galaxies in the ring, being at different distances but their projections just happening to form a rough circle would be even more astonishing than the galaxies in fact sharing a causal history due to some unknown early-universe mechanism.
The article also mentions that either the circle or the arc in itself could be just a statistical coincidence – as long as we dok’t find more such structures – but the existence of both the circle and the arc, in the same part of the sky, is highly suspicious.
Galaxies. And determining the approx relative distance of distant galaxies is in fact easy thanks to cosmological redshift (the z values the article refers to). Anyway, given the number of galaxies in the ring, being at different distances but their projections just happening to form a rough circle would be even more astonishing than the galaxies in fact sharing a causal history due to some unknown early-universe mechanism.
The article also mentions that either the circle or the arc in itself could be just a statistical coincidence – as long as we dok’t find more such structures – but the existence of both the circle and the arc, in the same part of the sky, is highly suspicious.
Woops. Yes, galaxies. Too late to edit.
> Anyway, given the number of galaxies in the ring, being at different distances but their projections just happening to form a rough circle would be even more astonishing than the galaxies in fact sharing a causal history due to some unknown early-universe mechanism.
I don't understand what you mean by this. Why would it be "more astonishing" than an actual causal connection? Surely astronomers are more interested in causal connections than observational coincidences?
To illustrate: the stars making up the constellation of Norma [1] form a rough square when seen from earth, but as their distances from Earth vary greatly this is just an illusion caused by Earth's relative orientation to them. Given the Copernican principle (which I accept is not a physical law) I'm struggling to see why a group of galaxies that form a circle only when seen from "near" earth [2] are actually cosmologically significant.
I accept that the ring contains more than four galaxies, and this makes the ring more statistically significant than a square of galaxies. But it still implies a privileged viewpoint in order for it to be actually significant. I still have the gut feeling that this potential significance is more than offset by the enormously greater observational scale.
tl/dr: why is this more than just naming a new constellation?
(Just to re-iterate: I'm interested in understanding the errors in my mental model - and I'm not trying to poke holes in the work of scientists more qualified them me.)
[1] https://en.wikipedia.org/wiki/Norma_(constellation)
[2] And also, I guess, from a similar point on the other "side" of the ring
> Anyway, given the number of galaxies in the ring, being at different distances but their projections just happening to form a rough circle would be even more astonishing than the galaxies in fact sharing a causal history due to some unknown early-universe mechanism.
I don't understand what you mean by this. Why would it be "more astonishing" than an actual causal connection? Surely astronomers are more interested in causal connections than observational coincidences?
To illustrate: the stars making up the constellation of Norma [1] form a rough square when seen from earth, but as their distances from Earth vary greatly this is just an illusion caused by Earth's relative orientation to them. Given the Copernican principle (which I accept is not a physical law) I'm struggling to see why a group of galaxies that form a circle only when seen from "near" earth [2] are actually cosmologically significant.
I accept that the ring contains more than four galaxies, and this makes the ring more statistically significant than a square of galaxies. But it still implies a privileged viewpoint in order for it to be actually significant. I still have the gut feeling that this potential significance is more than offset by the enormously greater observational scale.
tl/dr: why is this more than just naming a new constellation?
(Just to re-iterate: I'm interested in understanding the errors in my mental model - and I'm not trying to poke holes in the work of scientists more qualified them me.)
[1] https://en.wikipedia.org/wiki/Norma_(constellation)
[2] And also, I guess, from a similar point on the other "side" of the ring
> Woops. Yes, galaxies. Too late to edit.
Not even galaxies, but massive galaxy clusters. The spatial smoothing used for the ring image is a 2D gaussian with an equivalent width of 11 Mpc, or 37 million light years, big enough to contain all the 2000 galaxies in the nearby Virgo cluster with room to spare. That's for each point in the ring (and that's why they all look so nice and round. These astronomers are playing a statistical game where a pixel combines information from trillions of stars) It's called the Big Ring for a reason. Our own Laniakea supercluster [1], whose dimensions are bigger than anyone imagined up to a few years ago, can be tiled inside the ring several times over.
At that spatial scale, the Universe is supposed to be homogeneous. We do not have plausible mechanisms to generate structures on such a massive scale.
Regarding your analogy with a constellation, yes you can always draw arbitrary squares and triangles among bright stars. But if you had 20+ stars arranged in a circle like that ring, no one would think it was a chance projection, you would demand a physical explanation. We do in fact have such a ring around us: the Gould Belt [2], made of young stars all around the Sun. It is difficult to recognize precisely because we are inside it, and its stars are spread all around the sky. And, of course, some kind of physical explanation is invoked for this ring as well.
Moreover we do know it's an actual ring, and not some chance alignment, because we can derive the distance of each point from its redshift, and it turns out that they are all quite similar. The authors spend quite a few pages describing the 3D ring structure, showing that it's a ring only when seen from our direction, and how it would appear like an arc or a strange shape from other viewpoints. It would still be a kind of overdense structure, but maybe more difficult to recognize.
BTW the mechanism used to detect the ring is quite clever: it's not a sky image, but rather an absorption map: thousands of background quasars provide a sort of uniform illumination, and they look where this light is removed by clumps of matter.
[1] https://en.wikipedia.org/wiki/Laniakea_Supercluster
[2] https://en.wikipedia.org/wiki/Gould_Belt
Not even galaxies, but massive galaxy clusters. The spatial smoothing used for the ring image is a 2D gaussian with an equivalent width of 11 Mpc, or 37 million light years, big enough to contain all the 2000 galaxies in the nearby Virgo cluster with room to spare. That's for each point in the ring (and that's why they all look so nice and round. These astronomers are playing a statistical game where a pixel combines information from trillions of stars) It's called the Big Ring for a reason. Our own Laniakea supercluster [1], whose dimensions are bigger than anyone imagined up to a few years ago, can be tiled inside the ring several times over.
At that spatial scale, the Universe is supposed to be homogeneous. We do not have plausible mechanisms to generate structures on such a massive scale.
Regarding your analogy with a constellation, yes you can always draw arbitrary squares and triangles among bright stars. But if you had 20+ stars arranged in a circle like that ring, no one would think it was a chance projection, you would demand a physical explanation. We do in fact have such a ring around us: the Gould Belt [2], made of young stars all around the Sun. It is difficult to recognize precisely because we are inside it, and its stars are spread all around the sky. And, of course, some kind of physical explanation is invoked for this ring as well.
Moreover we do know it's an actual ring, and not some chance alignment, because we can derive the distance of each point from its redshift, and it turns out that they are all quite similar. The authors spend quite a few pages describing the 3D ring structure, showing that it's a ring only when seen from our direction, and how it would appear like an arc or a strange shape from other viewpoints. It would still be a kind of overdense structure, but maybe more difficult to recognize.
BTW the mechanism used to detect the ring is quite clever: it's not a sky image, but rather an absorption map: thousands of background quasars provide a sort of uniform illumination, and they look where this light is removed by clumps of matter.
[1] https://en.wikipedia.org/wiki/Laniakea_Supercluster
[2] https://en.wikipedia.org/wiki/Gould_Belt
> We do not have plausible mechanisms to generate structures on such a massive scale.
Actual structure no. But, random chance can make things look like a structure on this scale.
> But if you had 20+ stars arranged in a circle like that ring, no one would think it was a chance projection, you would demand a physical explanation.
I would generally assume it to be random. In galaxies stars move around far to much for any structure from their initial formation to remain for long, and forming a ring long after creation would just be happenstance.
Actual structure no. But, random chance can make things look like a structure on this scale.
> But if you had 20+ stars arranged in a circle like that ring, no one would think it was a chance projection, you would demand a physical explanation.
I would generally assume it to be random. In galaxies stars move around far to much for any structure from their initial formation to remain for long, and forming a ring long after creation would just be happenstance.
> But, random chance can make things look like a structure on this scale.
You can never absolutely prove that something isn’t random. However:
Galaxy distributions are pink noise, not white noise. Large scale structures are less probable.
The Komolgorov complexity of large structures is lower than random noise, and lower Komolgorov complexity usually indicates some non-random process.
A random process is less likely to produce structure than a non-random process.
You can never absolutely prove that something isn’t random. However:
Galaxy distributions are pink noise, not white noise. Large scale structures are less probable.
The Komolgorov complexity of large structures is lower than random noise, and lower Komolgorov complexity usually indicates some non-random process.
A random process is less likely to produce structure than a non-random process.
> I would generally assume it to be random.
But its not, it has structure - it looks like ring or arc. The universe should be homologous at this scale.
But its not, it has structure - it looks like ring or arc. The universe should be homologous at this scale.
Every formation of galaxies has structure.
Random processes can appear to have meaningful structure, but that’s just because we value some outcomes more than others.
> The universe should be homologous at this scale.
That doesn’t mean we’re going to perceive it as homologous. A true random number generator spitting out 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 would be freaky as fuck to see, but that doesn’t make it non random.
Random processes can appear to have meaningful structure, but that’s just because we value some outcomes more than others.
> The universe should be homologous at this scale.
That doesn’t mean we’re going to perceive it as homologous. A true random number generator spitting out 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 would be freaky as fuck to see, but that doesn’t make it non random.
For any allegedly-random distribution, it's possible to statistically determine an upper-limit on the size of non-random-appearing structures. The upper limit for such structures in our universe is thought to be about 370 MPc, about 1/3rd of the size of this ring.
A lot of these questions are much more clearly addressed in the previous paper by the same authors, which is much more layperson-friendly: https://academic.oup.com/mnras/article/516/2/1557/6657809?lo...
A lot of these questions are much more clearly addressed in the previous paper by the same authors, which is much more layperson-friendly: https://academic.oup.com/mnras/article/516/2/1557/6657809?lo...
I’m guessing the point is something along the lines of, if you have a page of randomly-distributed points, you would expect to see small features but a large circle spanning the page would be inexplicable.
That makes sense, thanks for actually explaining the core idea.
That makes sense, thanks for actually explaining the core idea.
[deleted]
This is true, but at this scale, aren’t we looking at a moderate portion of the visible universe? This is hundreds of thousands or millions of galaxies appearing with some strong correlation, I believe. There are only a few trillion galaxies in the observable universe, so it’s not like we have 10^20 chances to observe random chance correlations like this.
I’m just talking without actually having done a close reading or done the statistics for myself, so I could be quite wrong.
I’m just talking without actually having done a close reading or done the statistics for myself, so I could be quite wrong.
Check out the preprint: https://arxiv.org/pdf/2402.07591
It’s less impressive when looking at the background data than how it’s described.
It’s less impressive when looking at the background data than how it’s described.
[deleted]
> Random processes can appear to have meaningful structure, but that’s just because we value some outcomes more than others.
No. It's because some structures are much much much less likely to form randomly than other structures.
If you throw 1000 dices, is it possible to get all one? Yes. Is it likely? Not at all.
Why do planets look like a sphere (approximately)? Because that's the most probable shape if things happen randomly. If a pyramid-shaped planet was found, scientists would freak out. This galaxy ring phenomenon is similar to that (but not that crazy).
No. It's because some structures are much much much less likely to form randomly than other structures.
If you throw 1000 dices, is it possible to get all one? Yes. Is it likely? Not at all.
Why do planets look like a sphere (approximately)? Because that's the most probable shape if things happen randomly. If a pyramid-shaped planet was found, scientists would freak out. This galaxy ring phenomenon is similar to that (but not that crazy).
> Why do planets look like a sphere (approximately)? Because that's the most probable shape if things happen randomly.
That has actually nothing to do with randomness, and everything to do with gravity. https://spaceplace.nasa.gov/planets-round/en/
That has actually nothing to do with randomness, and everything to do with gravity. https://spaceplace.nasa.gov/planets-round/en/
which, to be clear, is the exact point the parent comment is making.
Randomness only favors something over noise if there is a non random process determining the structure
Randomness only favors something over noise if there is a non random process determining the structure
Finding ~50 dots arranged in a (very loosely defined) circle, from any projection, of a dense set of 2 trillion of them is very plausible.
Actually, you would have a hard time producing this set in such way that no "circles" like that are found at all. It would have to be a very artificial distribution of points in space for you not to observe this, like all of them arranged in a single line, or a giant rectangle, idk.
Actually, you would have a hard time producing this set in such way that no "circles" like that are found at all. It would have to be a very artificial distribution of points in space for you not to observe this, like all of them arranged in a single line, or a giant rectangle, idk.
> Finding ~50 dots arranged in a (very loosely defined) circle, from any projection, of a dense set of 2 trillion of them is very plausible.
It depends on the size of the circle, though. The smaller the size, the more likely the probability is. But that’s only for a particular combination of 50 dots. Now we have to average out of all possible circle sizes and all combinations of 50 dots. Can someone do the math (or the simulation)?
It depends on the size of the circle, though. The smaller the size, the more likely the probability is. But that’s only for a particular combination of 50 dots. Now we have to average out of all possible circle sizes and all combinations of 50 dots. Can someone do the math (or the simulation)?
On a first glance it seems so, but ... could it be the opposite?
I'm thinking, the larger the space, the larger the number of points contained within it, so the larger the probability of them being arrange in such way that blah blah ...
We need a math guy to chime in. I have a hunch there may be a theorem about something like this already.
I'm thinking, the larger the space, the larger the number of points contained within it, so the larger the probability of them being arrange in such way that blah blah ...
We need a math guy to chime in. I have a hunch there may be a theorem about something like this already.
> If you throw 1000 dices, is it possible to get all one? Yes. Is it likely? Not at all.
That's literally as likely as any other possible outcome.
Let's simplfy this to a coin toss, which is more likely:
HHHHHH
or
HHTHTT
or
HTHTHT
They all have the exact same odds of appearing, we might just tell ourselves one formation is more special than any other.
That's literally as likely as any other possible outcome.
Let's simplfy this to a coin toss, which is more likely:
HHHHHH
or
HHTHTT
or
HTHTHT
They all have the exact same odds of appearing, we might just tell ourselves one formation is more special than any other.
Of course each instance has the same probability. But we're not talking about the probability of an instance, but rather that of a set of instances.
In the dice example, it's obvious that the probability of getting at least one dice facing two is much more likely than the probability of getting all dice facing one.
Similarly, in the planet shape example, I hope you don't think that a pyramid-shaped planet is as likely to form as a sphere-shaped planet.
In the dice example, it's obvious that the probability of getting at least one dice facing two is much more likely than the probability of getting all dice facing one.
Similarly, in the planet shape example, I hope you don't think that a pyramid-shaped planet is as likely to form as a sphere-shaped planet.
Yes, a large set of instances is more likely than a single instance (all things being equal).
However that doesn't mean that a sphere is any more or less likely than any specific other structure. It's an small but important distinction.
No, a pyramid shaped planet is not as likely to form as a sphere shaped pyramid. Definitionally a pyramid shaped planet is impossible.
However that doesn't mean that a sphere is any more or less likely than any specific other structure. It's an small but important distinction.
No, a pyramid shaped planet is not as likely to form as a sphere shaped pyramid. Definitionally a pyramid shaped planet is impossible.
> However that doesn't mean that a sphere is any more or less likely than any specific other structure.
A shape/structure doesn't have an intrinsic probability. Your sentence is underspecified. Shape of what under what process?
In the context of the shape of galaxies, I think we can agree that if we found galaxies forming a shape like this sentence: "WE ARE COMING", everyone would freak out. So yeah, in this context, some shapes are more likely to form (randomly) than others.
A shape/structure doesn't have an intrinsic probability. Your sentence is underspecified. Shape of what under what process?
In the context of the shape of galaxies, I think we can agree that if we found galaxies forming a shape like this sentence: "WE ARE COMING", everyone would freak out. So yeah, in this context, some shapes are more likely to form (randomly) than others.
>> If you throw 1000 dices, is it possible to get all one? Yes. Is it likely? Not at all.
> That's literally as likely as any other possible outcome.
???
If you want any outcome, they're equally likely.
But the prev post chose a particular outcome, and any particular outcome is rare.
There's no contradiction.
So what's the insight?
This distinction is popularly represented by the "Monty Hall problem": should you take the offer of the other door.
The problem involves 3 doors with a prize behind only one, where you choose 1 of the three, then Monty shows you what's behind 1 of the remaining 2, which is not the prize, then asks you if you would like to switch to the remaining door.
You might think that your odds won't change because nothing behind the doors has changed, or might get worse because the offer is a second chance to pick the dud.
But instead of 3 doors, imagine 1000 doors. You pick 1. Monty shows you what's behind 998 that aren't the prize and asks you if you want to switch.
By switching, your 1-of-1000 odds become 1-of-2.
The particulars matter.
> That's literally as likely as any other possible outcome.
???
If you want any outcome, they're equally likely.
But the prev post chose a particular outcome, and any particular outcome is rare.
There's no contradiction.
So what's the insight?
This distinction is popularly represented by the "Monty Hall problem": should you take the offer of the other door.
The problem involves 3 doors with a prize behind only one, where you choose 1 of the three, then Monty shows you what's behind 1 of the remaining 2, which is not the prize, then asks you if you would like to switch to the remaining door.
You might think that your odds won't change because nothing behind the doors has changed, or might get worse because the offer is a second chance to pick the dud.
But instead of 3 doors, imagine 1000 doors. You pick 1. Monty shows you what's behind 998 that aren't the prize and asks you if you want to switch.
By switching, your 1-of-1000 odds become 1-of-2.
The particulars matter.
> But the prev post chose a particular outcome, and any particular outcome is rare.
No, we first observed a particular outcome (the giant ring). This would be like running coin flips for long enough, spotting some interesting sequence that wasn’t decided beforehand, then deciding it must not be random because that sequence should have been incredibly rare.
Sure, that sequence was rare but it was just as likely as all the other sequences which we didn’t end up seeing.
No, we first observed a particular outcome (the giant ring). This would be like running coin flips for long enough, spotting some interesting sequence that wasn’t decided beforehand, then deciding it must not be random because that sequence should have been incredibly rare.
Sure, that sequence was rare but it was just as likely as all the other sequences which we didn’t end up seeing.
> But instead of 3 doors, imagine 1000 doors. You pick 1. Monty shows you what's behind 998 that aren't the prize and asks you if you want to switch. By switching, your 1-of-1000 odds become 1-of-2.
No they should become 999 out of 1000. If your door is 1 in 1000 then the other door must have all other possibilities.
Also, the Monty haul problem is counter intuitive because it depends on the exact rules under which he operates. Suppose the classic 1 in 3 odds of a win, but an evil Monty haul where he only gives the option if you would win, now swapping is a guaranteed loss. Mathematically the answer is obvious when all the rules are guaranteed, but people’s internal heuristics don’t automatically trust rules as stated.
No they should become 999 out of 1000. If your door is 1 in 1000 then the other door must have all other possibilities.
Also, the Monty haul problem is counter intuitive because it depends on the exact rules under which he operates. Suppose the classic 1 in 3 odds of a win, but an evil Monty haul where he only gives the option if you would win, now swapping is a guaranteed loss. Mathematically the answer is obvious when all the rules are guaranteed, but people’s internal heuristics don’t automatically trust rules as stated.
> By switching, your 1-of-1000 odds become 1-of-2.
It's not 50/50. That means you had a 50% chance to get the door correct on the first guess out of 1000. By showing the non-winning doors, the odds collapse into the remaining door. You had a 1/1000 chance of getting it right the first time, after the reveal all 998 are now assigned to the remaining door.
It's not 50/50. That means you had a 50% chance to get the door correct on the first guess out of 1000. By showing the non-winning doors, the odds collapse into the remaining door. You had a 1/1000 chance of getting it right the first time, after the reveal all 998 are now assigned to the remaining door.
No: precisely that is the definition of randomness as “lack of information “ or “incompressibility”.
HH is just as compressible as HT or TH or TT.
You can easily build a compression scheme for any one of these values, but not one that encapsulates all values while using less data than the raw values themselves.
You can easily build a compression scheme for any one of these values, but not one that encapsulates all values while using less data than the raw values themselves.
This isn’t how randomness works. Given enough points plotted at random on the surface of a sphere, you’ll find the entire written works of Shakespeare scribed across it.
That doesn’t mean it was put there intentionally, just that given enough random samples any pattern will appear.
That doesn’t mean it was put there intentionally, just that given enough random samples any pattern will appear.
Thank you for taking the time to write such an informative response.
[deleted]
> But if you had 20+ stars arranged in a circle like that ring, no one would think it was a chance projection…
Of course we would? This is absolutely backwards.
A random plot of billions of points will have all sorts of coincidental shapes and clusterings. A uniform field might look more random but would actually demand explanation, as lacking those coincidental clusterings is strong evidence for structure.
And as I understand the topic, the scales involved preclude those galaxies physically interacting and being able to form structure. So they should appear randomly distributed.
Edit: To be clear I’m assuming my own ignorance here. I presume there is a reason this is significant, I just don’t understand it. But arguments like yours aren’t convincing to me because we should expect to see random structure, the same way a series of a billion coin flips is likely to have a giant run of alternating heads and tails.
Of course we would? This is absolutely backwards.
A random plot of billions of points will have all sorts of coincidental shapes and clusterings. A uniform field might look more random but would actually demand explanation, as lacking those coincidental clusterings is strong evidence for structure.
And as I understand the topic, the scales involved preclude those galaxies physically interacting and being able to form structure. So they should appear randomly distributed.
Edit: To be clear I’m assuming my own ignorance here. I presume there is a reason this is significant, I just don’t understand it. But arguments like yours aren’t convincing to me because we should expect to see random structure, the same way a series of a billion coin flips is likely to have a giant run of alternating heads and tails.
I'm interested in the part about using quasars to illuminate the galaxies. Are quasars so common that they provide a uniform background to the whole universe? I always thought they were fairly sporadically distributed.
Actually I do have a plausible mechanism whose numbers have been sanity checked by a couple of cosmologists, but has never been published.
Here's the idea. The expansion of the universe is currently accelerating. If this continues indefinitely, we get the https://en.wikipedia.org/wiki/Big_Rip model. What happens if the Big Rip proceeds to the point where a lot of https://en.wikipedia.org/wiki/Vacuum_energy gets released, and that release stops the Rip by creating the next Big Bang? This could form a cycle since the next Bang creates cosmos that in turn will Rip.
It doesn't sound entirely crazy to me. The Casimir effect shows that you should release vacuum energy when you constrain the volume that a particularly bit of space can interact with. The incredible expansion of a Rip should constrain such interactions. So a large release of vacuum energy seems expected. And who knows how releasing vacuum energy interacts with the acceleration of the expansion of the universe?
Let's do a back of the envelope estimate. Theory estimates vacuum energy at something like 10^113 joules per cubic meter of vacuum energy. For comparison the visible universe is estimated at 10^53 kg. Using Einstein's E = mc^2, that's around 10^70 joules. Current cosmological models say that at the hottest part of the Big Bang, the universe must have already been larger than a cubic meter. Yes, there is a lot of energy not in the form of visible matter. Even so, there's a lot of room for a release of vacuum energy to explain the energy density needed at the beginning of a Big Bang.
We at least pass the most basic sanity check.
This would offer interesting answers to some key cosmological questions.
Current Big Bang models struggle with how a large volume started out very uniform. Inflation has been proposed for this, but it has some problems. But in this model, extreme uniformity over a large volume is predicted. If you add in quantum fluctuations starting the vacuum release, that have spread out before we go from Rip to Bang, then you can also explain arbitrarily large structures in the universe.
This also explains the arrow of time. How could we start off with such low entropy when entropy is always increasing? Well as the universe expands, entropy increases. But volume increases faster. We wind up with a giant universe filled with very low entropy/volume. When a small piece of that forms a new Big Bang, it again starts with very low entropy.
Unfortunately, this involves an insane lack of conservation of energy. But GR provides no easy way to even state what conservation of energy means. At least not outside of limited classes of models. Which this is not one of. So the idea of energy not being conserved at cosmological scales is at least not entirely unprecedented by current theory.
Here's the idea. The expansion of the universe is currently accelerating. If this continues indefinitely, we get the https://en.wikipedia.org/wiki/Big_Rip model. What happens if the Big Rip proceeds to the point where a lot of https://en.wikipedia.org/wiki/Vacuum_energy gets released, and that release stops the Rip by creating the next Big Bang? This could form a cycle since the next Bang creates cosmos that in turn will Rip.
It doesn't sound entirely crazy to me. The Casimir effect shows that you should release vacuum energy when you constrain the volume that a particularly bit of space can interact with. The incredible expansion of a Rip should constrain such interactions. So a large release of vacuum energy seems expected. And who knows how releasing vacuum energy interacts with the acceleration of the expansion of the universe?
Let's do a back of the envelope estimate. Theory estimates vacuum energy at something like 10^113 joules per cubic meter of vacuum energy. For comparison the visible universe is estimated at 10^53 kg. Using Einstein's E = mc^2, that's around 10^70 joules. Current cosmological models say that at the hottest part of the Big Bang, the universe must have already been larger than a cubic meter. Yes, there is a lot of energy not in the form of visible matter. Even so, there's a lot of room for a release of vacuum energy to explain the energy density needed at the beginning of a Big Bang.
We at least pass the most basic sanity check.
This would offer interesting answers to some key cosmological questions.
Current Big Bang models struggle with how a large volume started out very uniform. Inflation has been proposed for this, but it has some problems. But in this model, extreme uniformity over a large volume is predicted. If you add in quantum fluctuations starting the vacuum release, that have spread out before we go from Rip to Bang, then you can also explain arbitrarily large structures in the universe.
This also explains the arrow of time. How could we start off with such low entropy when entropy is always increasing? Well as the universe expands, entropy increases. But volume increases faster. We wind up with a giant universe filled with very low entropy/volume. When a small piece of that forms a new Big Bang, it again starts with very low entropy.
Unfortunately, this involves an insane lack of conservation of energy. But GR provides no easy way to even state what conservation of energy means. At least not outside of limited classes of models. Which this is not one of. So the idea of energy not being conserved at cosmological scales is at least not entirely unprecedented by current theory.
It does not seem very plausible that professional astronomers have twice made this rookie mistake and no-one has noticed yet. Furthermore, if they were just doing what amounts to drawing circles and lines on a map of galaxies, they could have discovered thousands by now!
The rate at which we are collecting data far, far outpaces the speed at which it is being analyzed.
There will almost certainly be more discoveries like this as we continue surveying the cosmos with increasingly sensitive instruments.
There will almost certainly be more discoveries like this as we continue surveying the cosmos with increasingly sensitive instruments.
Well, yes, but my point is that, if these astronomers are finding circles and other structures without doing basic checks such as distance, they could find thousands right now, using nothing more than a chart of the known galaxies - and even bigger ones than they are reporting here. Thus, it is not plausible that they are omitting these basic checks.
I think of it in terms of degrees of freedom and statistical likelihood. If I throw a bunch of marbles on the floor and a few of them form a interesting shape that is one thing as they can only move on a plane. If I throw them in the air it is less likely to form a circle as now they are free to move in multiple directions and are not constrained to the plane. If 4 of those marbles align that is less likely than 20 of them happening to do so in a recognizable shape. 20 marbles in the air, each one being in just the right place relative to the 19 others in order to look like a circle when they can be in any position in space (vs. limited to a flat plane) is exceedingly unlikely.
Even more unlikely is that an arc appears next to the ring, that would make me start to wonder if something is affecting the marbles I throw into the sky.
Even more unlikely is that an arc appears next to the ring, that would make me start to wonder if something is affecting the marbles I throw into the sky.
But your view is a 2D projection, so you are eliminating that degree of freedom. It's equivalent to forcing them all to fall to the floor. If they form an actual ring in 3D space, that is far less probable.
Is it less likely even if we can view the marbles in the air from any angle?
There is also the multiple-endpoints principle to think about. The likelihood of this particular set of galaxies forming a ring is very low. The chance of some set of galaxies among all the billions in the sky doing this is much higher.
Then we notice and cherry-pick only the one interesting data point, we never notice all the mundane ones.
It's always difficult to tell if a popular-science article is really describing something unusual or if it's using selective perception to create the illusion of one. (I have no idea in this case.)
It's always difficult to tell if a popular-science article is really describing something unusual or if it's using selective perception to create the illusion of one. (I have no idea in this case.)
> The chance of some set of galaxies among all the billions in the sky doing this is much higher.
Of course in relative terms it's much higher, but it doesn't matter—what matters is the absolute value. 10^-100 is much larger than 10^-10000, but if something with the probability of 10^-100 happens, it's still "astonishing."
The probability of a particular planet has a shape of pyramid is so low. And yes, the probability of finding any planet in the universe that has a shape of pyramid is much higher, but still very low. If one was found, scientists would freak out.
Of course in relative terms it's much higher, but it doesn't matter—what matters is the absolute value. 10^-100 is much larger than 10^-10000, but if something with the probability of 10^-100 happens, it's still "astonishing."
The probability of a particular planet has a shape of pyramid is so low. And yes, the probability of finding any planet in the universe that has a shape of pyramid is much higher, but still very low. If one was found, scientists would freak out.
It's unusual, at the very least. Because it's relatively close to us.
The infinite does not necessarily contain everything. I would be surprised to find an even number in an infinite list of odd numbers. I would be even more surprised to find cantor’s diagonalized number in a list of rational numbers. And yet even more surprised to find Hamlet encoded within Pi.
Structure is still interesting.
In re: the non-causal alignment being even more astonishing - a simple argument to illustrate this is to ask- would you be more amazed if you threw 100 bouncy balls in a room, took a photo and they formed a perfect circle in mid air at that instant from that angle, or if you went and placed the marbles one by one in a perfect circle on the ground and took a photo?
The latter might be more meaningful, but the former is more miraculous - not in a religious sense of course, but just in the sense of the extraordinary unlikelihood of catching such a moment of chance alignment in noise, apophenic divinity, in how it seems to violate the second law, etc etc.
It might be instructive for you to try look up Piero Della Francesca’s method of generating perspective images from a point cloud (from the 14th century no less - he invented 3D face scanning then!) and try a few manual examples to really wrap your head around how difficult it would be for a perfect circle to emerge from a truly random point cloud.
Structure is still interesting.
In re: the non-causal alignment being even more astonishing - a simple argument to illustrate this is to ask- would you be more amazed if you threw 100 bouncy balls in a room, took a photo and they formed a perfect circle in mid air at that instant from that angle, or if you went and placed the marbles one by one in a perfect circle on the ground and took a photo?
The latter might be more meaningful, but the former is more miraculous - not in a religious sense of course, but just in the sense of the extraordinary unlikelihood of catching such a moment of chance alignment in noise, apophenic divinity, in how it seems to violate the second law, etc etc.
It might be instructive for you to try look up Piero Della Francesca’s method of generating perspective images from a point cloud (from the 14th century no less - he invented 3D face scanning then!) and try a few manual examples to really wrap your head around how difficult it would be for a perfect circle to emerge from a truly random point cloud.
If Pi is normal, which we haven't proven but do suspect to be true, then it contains Hamlet, and indeed the entire works of Shakespeare in chronological order, an infinite number of times. https://en.wikipedia.org/wiki/Normal_number
Of course! But we haven’t been proven it yet. And in any case, knowing something exists is quite different than actually observing it. I know every night in Vegas, so many people will hit my lucky number (7, boring I know) on a roulette wheel that it is a perfectly ordinary event with no significance, and yet I would be ecstatic if it happened to me and would certainly be feeling lucky (and so I don’t gamble!). Even if Pi is indeed normal, it would still certainly be beyond surprising to stumble across the complete works of Shakespeare. In fact, from a cultural point of view, it would be a somewhat earth-shattering event! Imagine the headlines! Maybe not, maybe no one would care. It would certainly be shocking to anyone with half a brain cell, even if they knew it had to be somewhere… to find one such particular region is just so improbable that it would be undeniably… cool?
My point is that structure emerging out of noise, even if by mere coincidence, is still deeply interesting on a human, psychological level. Another commenter described the original paper as astrology, essentially arguing that it is bad science… maybe that is the case, but I think there is still room for some form of… confusion, estrangement, awe? in observing these sorts of phenomenon, even in scientific discourse every now and then. It’s vaguely like a piece of meaningless but none-the-less captivating art emerging out of the complex technological and discursive apparatuses of science.
My point is that structure emerging out of noise, even if by mere coincidence, is still deeply interesting on a human, psychological level. Another commenter described the original paper as astrology, essentially arguing that it is bad science… maybe that is the case, but I think there is still room for some form of… confusion, estrangement, awe? in observing these sorts of phenomenon, even in scientific discourse every now and then. It’s vaguely like a piece of meaningless but none-the-less captivating art emerging out of the complex technological and discursive apparatuses of science.
[deleted]
Well, infinity absolutely would contain everything - there would be Adam's planet that grows Phillips screwdrivers, which is of course absurd but infinity so... universe isn't infinite tho
I don't kno why ppl believe that it is. It's very big, we have no frame of reference bc it literally contains all possible known frames of reference and even with that in mind, we need a bigger thing to grasp how big it is, we won't ever have that perspective.
That doesn't make the universe infinite tho. Even if the universe is expanding at a rate greater than we could ever catch the other galaxies and this expansion limitlessly expands the universe, THAT is still not infinite.
There is no infinite thing bc nothing is infinite for real, it's an idea
I don't kno why ppl believe that it is. It's very big, we have no frame of reference bc it literally contains all possible known frames of reference and even with that in mind, we need a bigger thing to grasp how big it is, we won't ever have that perspective.
That doesn't make the universe infinite tho. Even if the universe is expanding at a rate greater than we could ever catch the other galaxies and this expansion limitlessly expands the universe, THAT is still not infinite.
There is no infinite thing bc nothing is infinite for real, it's an idea
Looking at the angular size of the region in question, it surely would have to be that they’re equidistant from us in order to be at all interesting. There should be innumerable galaxies in and around the ring, from our perspective.
here's a picture from her presentation
https://www.youtube.com/watch?v=fwRJGaIcX6A&t=173s
https://www.youtube.com/watch?v=fwRJGaIcX6A&t=173s
I would argue that your keen interest in learning more about natural things that are mysterious to you by asking questions and doing research literally makes you a scientist.
Not a professional one in the field, sure. But scientist? Most assuredly.
Not a professional one in the field, sure. But scientist? Most assuredly.
Carl Sagan would agree. In his book The Demon Haunted World he explains science in very similar terms as you. He also gives examples of primitive humans doing science.
But is he doing research? Has he read on the Cosmological Principle? Maybe some reading on what standard deviation (5.2σ on this paper) is and what it means to things being naturally random? How about reading the original paper? The Discussion section makes it very, very clear how the scientists reached the conclusion and how the Big Ring is statistically significant -- and in the process literally answering OP's question.
> Not a professional one in the field, sure. But scientist? Most assuredly.
Of course he's not a professional scientist!!!
To be one you have to partake in academic politics, with its legendarily low stakes, in a publish or perish environment ... for little more than minimum-wage.
Of course he's not a professional scientist!!!
To be one you have to partake in academic politics, with its legendarily low stakes, in a publish or perish environment ... for little more than minimum-wage.
Thank you!
If they are in a ring, equidistant, then whatever caused their arrangement would be local and roughly the same size/shape. But if there are at varying distances, then they would be arranged into a cone, a cone pointing directly at our galaxy. That would be a much more massive structure and, frankly, rather terrifying.
from Figure 1 (page 5 of the PDF) https://arxiv.org/pdf/2402.07591:
> The tangent-plane distribution of Mg II absorbers in the redshift slice z = 0.802 ± 0.060.
the ring is visible in the slice, which corresponds to a distance range based on those redshift values and cosmological parameters. I think this is effectively a spherical shell of a certain thickness.
> The tangent-plane distribution of Mg II absorbers in the redshift slice z = 0.802 ± 0.060.
the ring is visible in the slice, which corresponds to a distance range based on those redshift values and cosmological parameters. I think this is effectively a spherical shell of a certain thickness.
I don't think you have to add a disclaimer that you're not a scientist to (what looks to me to be) not-unreasonable speculations.
I mean, even if you were a scientist[1], odds are good you're not that kind of scientist.
Sort of like "I'm not a lawyer, but even if I were, I'm not YOUR lawyer."
[1] I was a scientist, and but not this kind of scientist, so your musings look just as plausible, if not more, than my own would.
I mean, even if you were a scientist[1], odds are good you're not that kind of scientist.
Sort of like "I'm not a lawyer, but even if I were, I'm not YOUR lawyer."
[1] I was a scientist, and but not this kind of scientist, so your musings look just as plausible, if not more, than my own would.
To be honest it's not clear if it's from our point of view or not, since they don't mention it explicitly in the paper, but it seems to be the case since they start from observations made by the Apache Point Observatory, which is on Earth ...
If you think about it, it doesn't matter which point of view it works on, if the thing is an actual circle that's interesting on its own, or presumably a sphere(?) but they don't even touch on that because "3D is hard"? Anyway, for some reason they implicitly choose our point of view as the "interesting one", funny (/s, actually lame and sad) to see the geocentric model is still alive after two millennia!
They also didn't check if other stars would form circles from any arbitrary point of view (how many circles are actually up there, not just the apparent ones), which would be a trivial calculation, but I guess "matrix transformations are hard" as well?
The whole paper is pretty weak. They calculate the "thickness" of this "circle", i.e. the distance from the galaxy closest to us to the galaxy further from us if you undo the projection; and they come up with a value of ~400 Megaparsecs. Now, you may be inclined to think "yeah, but the universe is HUGE and on that scale they may be kind of tighly packed?". Nope! It's on the order of the largest (actual) cosmological structures that we have identified, so, pretty much, they are as further away as they can be from each other, lol.
This is pretty much astrology.
Source: I read the paper.
If you think about it, it doesn't matter which point of view it works on, if the thing is an actual circle that's interesting on its own, or presumably a sphere(?) but they don't even touch on that because "3D is hard"? Anyway, for some reason they implicitly choose our point of view as the "interesting one", funny (/s, actually lame and sad) to see the geocentric model is still alive after two millennia!
They also didn't check if other stars would form circles from any arbitrary point of view (how many circles are actually up there, not just the apparent ones), which would be a trivial calculation, but I guess "matrix transformations are hard" as well?
The whole paper is pretty weak. They calculate the "thickness" of this "circle", i.e. the distance from the galaxy closest to us to the galaxy further from us if you undo the projection; and they come up with a value of ~400 Megaparsecs. Now, you may be inclined to think "yeah, but the universe is HUGE and on that scale they may be kind of tighly packed?". Nope! It's on the order of the largest (actual) cosmological structures that we have identified, so, pretty much, they are as further away as they can be from each other, lol.
This is pretty much astrology.
Source: I read the paper.
> To be honest it's not clear if it's from our point of view or not, since they don't mention it explicitly in the paper, but it seems to be the case since they start from observations made by the Apache Point Observatory, which is on Earth
Would the perspective difference be significant even if it were far out into the solar system?
Would the perspective difference be significant even if it were far out into the solar system?
Yes, of course, a 2D circle could appear as a line from a certain perspective in 3D space.
I don't think a ring of galaxies is going to look very different from anyplace within the solar system. Anyway I think moralestapia's point is that the circle might not be centered on us, so the redshift of the galaxies would not be the same. We could still determine that a circle exists by plotting the galaxies in 3D.
No, I mean, a 2D circle could appear as a line from a certain perspective in 3D space.
Spin up your mental model of a circle in 3D space, look at it from a vector perpendicular from its diameter, rotate it 90 degrees in any other axis but the one you're looking at it; on that 2D projection, it will be a line.
Spin up your mental model of a circle in 3D space, look at it from a vector perpendicular from its diameter, rotate it 90 degrees in any other axis but the one you're looking at it; on that 2D projection, it will be a line.
>No, I mean, a 2D circle could appear as a line from a certain perspective in 3D space.
Right, and as a matter of fact that's exactly what we DO see with the Milky Way galaxy. It can be conceived of as a circular disc, more or less, but in our sky we see it from the side, as a streak or a band rather than a disc.
Right, and as a matter of fact that's exactly what we DO see with the Milky Way galaxy. It can be conceived of as a circular disc, more or less, but in our sky we see it from the side, as a streak or a band rather than a disc.
But of all perspectives in 3D space, there are only a fraction of perspectives that see it as a line. Most other perspectives see it as a circle/ellipse. So, the earth's perspective is not that unique—in fact, it's the most common.
> Anyway, for some reason they implicitly choose our point of view as the "interesting one", funny (/s, actually lame and sad) to see the geocentric model is still alive after two millennia!
> They also didn't check if other stars would form circles from any arbitrary point of view (how many circles are actually up there, not just the apparent ones),
I think (not sure of the proof) that any set of points that form a circle from a specific PoV would, from any arbitrary PoV form a regular shape (ellipse) or a straight line.
So we can probably tell if any group of stars/galaxies/bright-lights-in-the-sky form a "structure" (i.e. a regular shape).
> They also didn't check if other stars would form circles from any arbitrary point of view (how many circles are actually up there, not just the apparent ones),
I think (not sure of the proof) that any set of points that form a circle from a specific PoV would, from any arbitrary PoV form a regular shape (ellipse) or a straight line.
So we can probably tell if any group of stars/galaxies/bright-lights-in-the-sky form a "structure" (i.e. a regular shape).
If the ring rotated, and black hole density decreases with size (https://www.youtube.com/watch?v=71eUes30gwc), could a rotating Gödel universe exist within our universe?
Could a region of space be engineered to allow for a limited form of time travel?
Could a region of space be engineered to allow for a limited form of time travel?
No, is the short answer. What you'd need is space-time rotating, not something physical rotating. If you could make the things rotate because space-time was rotating, not because they were, then yes, but there's no mechanism we know of which could do that.
I agree with the no, but you can make space itself rotate because things in space rotate: https://en.wikipedia.org/wiki/Frame-dragging
And that in turn would rotate things in space... or not?
The Lense-Thirring effect is absolutely a thing, and we have direct evidence for it. To be clearer (I totally wasn't clear enough on this tbf), there's nothing we know of which can do it at the required scale to allow for time travel.
What we're talking about here are closed timelike curves. There's models which suggest they could exist inside a singularity, but they're not going to outside without something which seriously breaks other areas of physics (Tipler cylinders etc).
What we're talking about here are closed timelike curves. There's models which suggest they could exist inside a singularity, but they're not going to outside without something which seriously breaks other areas of physics (Tipler cylinders etc).
> There's models which suggest they could exist inside a singularity, but they're not going to outside without something which seriously breaks other areas of physics (Tipler cylinders etc).
A singularity is a dimensionless point. It has no inside. Did you mean a black hole? If so, the Kurtzgesagt cartoon explains this.
The second part of you sentence seems to have a broken sentence structure. Can't make sense of it.
A singularity is a dimensionless point. It has no inside. Did you mean a black hole? If so, the Kurtzgesagt cartoon explains this.
The second part of you sentence seems to have a broken sentence structure. Can't make sense of it.
To clarify the rest of the sentence for you:
...but [closed time-like curves are] not going to [exist] outside [of a singularity] without something which seriously breaks other areas of physics (Tipler cylinders etc. [are examples of such theoretical instances which would break other areas of physics]).
...but [closed time-like curves are] not going to [exist] outside [of a singularity] without something which seriously breaks other areas of physics (Tipler cylinders etc. [are examples of such theoretical instances which would break other areas of physics]).
Are you familiar with the equations? I'm not prepared to simply take your word for it.
In short, this seems to say the exact opposite of your claim: https://en.wikipedia.org/wiki/Dust_solution
In short, this seems to say the exact opposite of your claim: https://en.wikipedia.org/wiki/Dust_solution
[deleted]
You're on the wrong thing there. I could be wrong but I think you're outside your field on this one.
It says that spacetime exists as an interaction of gravity alone. This implies that there is no other frame of reference in this type of solution to GR. i.e. without mass there is no time in such a universe. Not a new idea.
> I could be wrong but I think you're outside your field on this one.
And in contrast what would that make of you??
I'm saying that if there in some point in the future (because we can see it now) is sufficient mass density in the region of space of that big ring, and it is rotating, we tick every box we know of to theoretically allow for an eternal circle. "Engineering" it would mean that someone wanted some type of eternal existence, which is the profound idea at play here.
Engineering things without the technology to manufacture it happens all the time. Just because we can't imagine how to build it does not mean we can't calculate if it could exist.
> I could be wrong but I think you're outside your field on this one.
And in contrast what would that make of you??
I'm saying that if there in some point in the future (because we can see it now) is sufficient mass density in the region of space of that big ring, and it is rotating, we tick every box we know of to theoretically allow for an eternal circle. "Engineering" it would mean that someone wanted some type of eternal existence, which is the profound idea at play here.
Engineering things without the technology to manufacture it happens all the time. Just because we can't imagine how to build it does not mean we can't calculate if it could exist.
Where in the Wikipedia page does it seem say so? I can't find anything relevant but then again I don't understand all of it.
> A perfect and pressureless fluid can be interpreted as a model of a configuration of dust particles that locally move in concert and interact with each other only gravitationally, from which the name is derived.
That "only" is important but unintuitive. It means space and time can not be separated from mass.
That "only" is important but unintuitive. It means space and time can not be separated from mass.
Are you trying to say the ring is proof that something assembled the stars as such to engineer an eternal circle, intentionally - the intent being the profound thing?
Light travels very fast but space is very big, so the light from stars we see is very old - some of the lights have outlived their stars, so I assume you meant the past but tbh I'm unsure
Light travels very fast but space is very big, so the light from stars we see is very old - some of the lights have outlived their stars, so I assume you meant the past but tbh I'm unsure
It absolutely does not. "Interact with each other only gravitationally" has its plain and ordinary meaning: we're ignoring other interactions. No charge, no collisions, no radiation, etc.
[deleted]
Similar to the plot of https://en.wikipedia.org/wiki/Ring_(Baxter_novel)
Yes, though the Kurtzgesagt video seems to allow for a Kerr metric to be habitable in a very normal sense.
Does anyone know how fast the big ring in the sky keeps on turning?
I don't know where I'll be tomorrow, but I understood your reference today.
Interesting journey.
a year or more
Reminded me of the circles in the sky method that might help studying the topological structure of the universe.
https://mphitchman.com/geometry/section8-3.html
(I think I read about it first in “The shape of space” book)
https://mphitchman.com/geometry/section8-3.html
(I think I read about it first in “The shape of space” book)
Could we be watching in the wrong direction? Finding patterns where there is random noise is one of our characteristics. Or something closer than distorts our view of that region.
In the other hand, complexity sometimes lead to unexpected regularities, maybe things were not so even around the Big Bang.
In the other hand, complexity sometimes lead to unexpected regularities, maybe things were not so even around the Big Bang.
It is a weird structure because it is a helix, and not a ring.
Dr. Becky covers these sorts of phenomena in an accessible format:
https://www.youtube.com/@DrBecky/videos
Dr. Becky covers these sorts of phenomena in an accessible format:
https://www.youtube.com/@DrBecky/videos
It's obviously a Kardashev Type III[1] civilization.
[1] https://en.wikipedia.org/wiki/Kardashev_scale
[1] https://en.wikipedia.org/wiki/Kardashev_scale
Or a weird lens effect. Gravitational lensing has a logarithmic effect doesn’t it? Theres the old joke about fitting a line to log scale data with a fat enough pen. These galaxies aren’t perfectly circular to each other.
I think the fact that the arc has a similar focus to the ring is going to turn out to be something.
I think the fact that the arc has a similar focus to the ring is going to turn out to be something.
Cool insight. Anyone with more knowledge care to weigh in? Some supermassive dark matter there? Also, on what timeframe might this change if so? Note to self to Google this topic in a year.
This was my first thought also, and there's no mention of whether or not this possibility has been investigated.
While I doubt that explanation will hold, it is true that cosmological distances are where we should be looking for ET civilizations, as at those distances one can avoid the Fermi argument (although such a discovery would be pretty firm evidence we'll never achieve FTL travel.)
I don't know, cosmological distances might be too early for biological life to form and evolve intelligence and expand across galaxies. My understanding is that there weren't necessarily enough of the basic chemicals of life formed until relatively recently. (Phosphorus particularly is a problem, I'm less sure about the others) And doing anything visible across light years also takes a long time, especially if FTL is impossible, which it almost certainly is.
That's all true, to some extent, but at least it's not ruled out by Fermi.
It's not just one galaxy. It's a ring of galaxies.
I'm reading Stephen Webb's book (If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY), and he describes how a partial Dyson sphere can turn a star into a spaceship which blew my mind (just cover all but one side, the released energy will push it the other direction). Imagine doing that at the Galactic scale.
>just cover all but one side, the released energy will push it the other direction
What is to stop the star from just crashing into the sphere?
What is to stop the star from just crashing into the sphere?
In the book he discusses the shkadov thruster which reflects the energy so the shell would move, too.
Obviously if it's not reflective you could absorb the energy and use it as needed
https://en.m.wikipedia.org/wiki/Stellar_engine
Obviously if it's not reflective you could absorb the energy and use it as needed
https://en.m.wikipedia.org/wiki/Stellar_engine
Type IV or V, more like.
Adjust some galaxies in the early timeline and changes would appear downstream as if they were always there. For affected lifeforms, these structures (e.g. a smiley face or whathaveyou) would appear upon waking in the present morning to the data, yet when the affected search their memories, the structure would have always been there.
Unlikely configurations could be interpreted as communication from beings more advanced than typically imagined, or as cosmic engineering projects, or perhaps more likely, the shape of the universe is just different than previously imagined.
Unlikely configurations could be interpreted as communication from beings more advanced than typically imagined, or as cosmic engineering projects, or perhaps more likely, the shape of the universe is just different than previously imagined.
Ah, good, we've finally found Boulder's Ring. Weird that it's not in the middle of the Great Attractor, but maybe this was just the Xeelee's prototype.
The Cosmological Principle has been suspect for a long time. It just adds so little value and costs so much to our understanding of the universe. Best to stick to provable things.
Little value? It's one of the assumptions that lead us to the prediction of the CMB which we then found. It's proved very fruitful, I'd say. Without the cosmological principle, modern cosmology is a complete non-starter. I'm not aware of any serious theories whatsoever that even attempt to explain anything without the cosmological principle or at least an approximation thereof.
I recall the CMB being found accidentally, and then becoming evidence for the big bang. You don't need cosmological homogeneity to predict the CMB.
It was predicted, then found accidentally. https://www.ifi.unicamp.br/~assis/Apeiron-V2-p79-84(1995).pd... gives a date of 1948 for the following (Ralph Alpher and Robert Herman):
> The temperature of the gas at the time of condensation was 600 K., and the temperature in the Universe at the present time is found to be about 5 K. We hope to pub- lish the details of these calculations in the near future.
https://en.wikipedia.org/wiki/Discovery_of_cosmic_microwave_... describes the kinda-accidental confirmation of this theory.
> The temperature of the gas at the time of condensation was 600 K., and the temperature in the Universe at the present time is found to be about 5 K. We hope to pub- lish the details of these calculations in the near future.
https://en.wikipedia.org/wiki/Discovery_of_cosmic_microwave_... describes the kinda-accidental confirmation of this theory.
Your memory deceives you. The CMB was found accidentally in the sense that its discoverers were simply trying to reduce noise and found this one stubborn source, but it was predicted by Alpher twenty years prior.
Can you go into how you would predict it without homogeneity? Without homogeneity you don't get the FLRW metric, so you won't get the big bang or expansion, so no hot dense state in the past, thus no CMB.
Can you go into how you would predict it without homogeneity? Without homogeneity you don't get the FLRW metric, so you won't get the big bang or expansion, so no hot dense state in the past, thus no CMB.
Well, I'm not a physicist, but, from Wikipedia:
> In a strictly FLRW model, there are no clusters of galaxies or stars, since these are objects much denser than a typical part of the universe. Nonetheless, the FLRW model is used as a first approximation for the evolution of the real, lumpy universe because it is simple to calculate...
So unless there's a really strong dependency on the size of the lumps, what breaks on the path from there to something observationally close-enough to the CMB? I mean, I know inflation is a factor there, but that very much postdates the first ideas of the big bang so it can't invalidate the basic idea.
Ed: basically what I'm saying is, there are a lot of routes to a CMB-like prediction based on our observations, and I very much doubt they all get broken by lack of a cosmological principle.
> In a strictly FLRW model, there are no clusters of galaxies or stars, since these are objects much denser than a typical part of the universe. Nonetheless, the FLRW model is used as a first approximation for the evolution of the real, lumpy universe because it is simple to calculate...
So unless there's a really strong dependency on the size of the lumps, what breaks on the path from there to something observationally close-enough to the CMB? I mean, I know inflation is a factor there, but that very much postdates the first ideas of the big bang so it can't invalidate the basic idea.
Ed: basically what I'm saying is, there are a lot of routes to a CMB-like prediction based on our observations, and I very much doubt they all get broken by lack of a cosmological principle.
I don't like playing that card, but I am a physicist, a cosmologist actually, and I wrote in my last post how it breaks. And I used the qualifier "approximation" in my first post of this thread. If you don't assume homogeneity on large scales you don't get a big bang. Or at least I'm not aware of any of the routes you are talking about. Even observing receding galaxies does not necessarily imply a big bang, which is why the debate wasn't settled until the discovery of the CMB. Until then, the steady state universe was still viable, which is basically an eternally expanding universe.
Are the features in the article big enough to break the CMB predictions? I'm kind of taking it from the article and surrounding works that they're big enough to break cosmological homogeneity as commonly understood, but maybe that's wrong too.
Please be un-natural and custom-made.
Too bad a ring is still too easy to get created naturally. If it would have had the shape of a square, or a dogecoin, that'd get really interesting
custom made arrangement of galaxies??
Aliens - custom-made. I didn't want to say man-made!
This can’t be alien-made. That’s 9.2 billion years old. The universe was too young back then to allow life to evolve. Not only that, but for a civilization to reach that kind of technological level it could easily have taken them another billion years.
I don't think we can rule it out.
The current universe conditions have existed for about 12.8 billion years, and while it might have taken 4.5 billion years for vertebrates to evolve on earth, other planets might have taken faster paths to self-awareness.
I figure an "intelligent sludge" could easily have evolved within a billion years of planet formation. Something that wasn't even fully multicellular, but could work together to produce intelligence in a community of loosely connected homogeneous cells. And if that lifeform gained the ability to intelligently manipulate its own DNA (or equivalent), it could bypass the whole next stages of evolution. Or it could go straight for technology.
The current universe conditions have existed for about 12.8 billion years, and while it might have taken 4.5 billion years for vertebrates to evolve on earth, other planets might have taken faster paths to self-awareness.
I figure an "intelligent sludge" could easily have evolved within a billion years of planet formation. Something that wasn't even fully multicellular, but could work together to produce intelligence in a community of loosely connected homogeneous cells. And if that lifeform gained the ability to intelligently manipulate its own DNA (or equivalent), it could bypass the whole next stages of evolution. Or it could go straight for technology.
The oldest stars would have been 4.5 billion years old by then.
Wild speculation: It's the result of another universe poking into our own, forcing a bunch of galaxies near the center point to spread out in a circular fashion.
More wild speculation: an expansion point in the previous universe, centred perfectly on a quark-antiquark pair.
and more: simulation artifact
This is pretty incredible...I honestly would be facinated to find out what sort of early universe event might have precipitated such a massive structure
Looks like Niven was thinking too small when he imagined Fleet of Worlds being made of just 5 stars.
Niven walked so that Baxter could run.
Within 2 trillion galaxies and 10^24 stars, it would be statistically rare not to find any arrangement following a shape that's familiar to us.
[deleted]
Is this the center of the universe then? Maybe the big band originated from the center of that ring.
Rings imply orbit. Could they be orbiting around an insanely-large unseen black hole?
Do we have a guess what does the ring look like X million/billion years ago?
Yes, we have direct observations. /s
The light we are viewing now was emitted billions of years ago, we don't know what it looks like today.
The light we are viewing now was emitted billions of years ago, we don't know what it looks like today.
Something so key to the news, and yet not mentioned in this article.
The ring we see is how it looked 9 billion years ago. The universe is 14 billion years old. So, when the universe was still a baby.
The ring we see is how it looked 9 billion years ago. The universe is 14 billion years old. So, when the universe was still a baby.
Sorry I meant to say...eh...maybe something from a few decades ago so to capture tiny changes.
Looks like Galactic Union )
that people refuse to accept that it is a structure and not mirage formed by a privileged angle gives homage to its statistical improbability
Time to revisit Larry Niven's work I think.
Try Stephen Baxter, if we're working on these sorts of scales.
I mean.. you would expect to see rings sometimes if this is a random noise kind of distribution no?
Structures yes, but not at this sort of scale. For reasons*, there's a soft limit on the scale that you'd expect structures** to scale to. There's no technical reason why they can't get bigger, it just becomes spectacularly unlikely that you'd ever get one. The fact that we've found two so far means 1. There's probably more we haven't found yet, and thus they're probably*** more common than we'd expect, and 2. There may be some mechanism we don't yet understand which leads to the emergence of astronomical structures at this sort of scale.
* Actually quite interesting reasons, but which take a lot of maths to explain that I'm not going in to here.
** In this case, defined as a thing or set of things in a mathematically simple shape - spheres, rings etc.
*** Assuming any bit of the universe is roughly like any other bits, and we didn't just happen to fluke on literally the only place where these exist, and there's two.
* Actually quite interesting reasons, but which take a lot of maths to explain that I'm not going in to here.
** In this case, defined as a thing or set of things in a mathematically simple shape - spheres, rings etc.
*** Assuming any bit of the universe is roughly like any other bits, and we didn't just happen to fluke on literally the only place where these exist, and there's two.
Can you give references on the *reasons? Would love to try to do some maths reading in a long while.
If you want to do some research on the subject, you're looking for violations of homogeneity, as implied by the Lambda-CDM model of the universe. The lambda in this case is the cosmological constant. You'll need to read up on that too.
The shortest, simplest way I can think to explain it is that we expect the universe to look alike, anywhere we look. Think of it like a biopsy - we assume that anywhere we look should be much like anywhere else, because there's no reason to think any area of the universe has special conditions where physics plays by different rules.
That sets up some implications around what we think the universe should look like, at different scales. However, we recently have been running into structures which are bigger than we'd expect.
Where we get into the maths is to do with the value of the cosmological constant. We currently think it's positive, because the universe is expanding, and its rate of expansion is accelerating. To look into the maths for this, have a Google around the maths behind the accelerating expansion of the universe.
The shortest, simplest way I can think to explain it is that we expect the universe to look alike, anywhere we look. Think of it like a biopsy - we assume that anywhere we look should be much like anywhere else, because there's no reason to think any area of the universe has special conditions where physics plays by different rules.
That sets up some implications around what we think the universe should look like, at different scales. However, we recently have been running into structures which are bigger than we'd expect.
Where we get into the maths is to do with the value of the cosmological constant. We currently think it's positive, because the universe is expanding, and its rate of expansion is accelerating. To look into the maths for this, have a Google around the maths behind the accelerating expansion of the universe.
>but which take a lot of maths to explain that I'm not going in to here
Yeah, bs.
Provide sources to support you argument, that's entry level discourse.
Yeah, bs.
Provide sources to support you argument, that's entry level discourse.
If you follow the link from this article to the preprint, you'll find some explanations, references to other papers, as well as enough terminology to do some Googling.
Have fun! It's quite interesting.
Have fun! It's quite interesting.
Yeah, read the site guidelines, yo.
I actually read the article, as you can see by the other comments I've made, and found none of that, but please feel free to correct me and cite here the portions of the paper where that is mentioned.
And sure, I could specialize in cosmology and find out the reasons on my own, but also, the burden of proof on that argument is not on me.
I actually read the article, as you can see by the other comments I've made, and found none of that, but please feel free to correct me and cite here the portions of the paper where that is mentioned.
And sure, I could specialize in cosmology and find out the reasons on my own, but also, the burden of proof on that argument is not on me.
Introduction, paragraph 2:
>The multiple discoveries of LSSs made throughout the past few decades are well known to challenge our understanding of the Standard Cosmological Model (ΛCDM) [2, 8–12], in particular due to a possible violation of a fundamental assumption, the Cosmological Principle (CP), which states that our Universe is both homogeneous and isotropic on large scales
That gives you a couple papers and a few terms that you can get started with. Unless your goal is to argue, instead of learn, which it seems like it might be.
>The multiple discoveries of LSSs made throughout the past few decades are well known to challenge our understanding of the Standard Cosmological Model (ΛCDM) [2, 8–12], in particular due to a possible violation of a fundamental assumption, the Cosmological Principle (CP), which states that our Universe is both homogeneous and isotropic on large scales
That gives you a couple papers and a few terms that you can get started with. Unless your goal is to argue, instead of learn, which it seems like it might be.
Context, as it seems to have been missed:
>For reasons*, there's a soft limit on the scale that you'd expect structures** to scale to.
The content you cited acknowledges the premise of the Cosmological Principle, but it does not say anything about what these "reasons" could be.
So, nope, that's not an adequate argument.
Again, I could waste my time on a PhD in Cosmology to come back and actually make a good argument for why homogeneity in structure is favored at large cosmological scales ... but why should I? I didn't bring that particular argument into the conversation [1].
1: https://en.wikipedia.org/wiki/Burden_of_proof_(philosophy)
>For reasons*, there's a soft limit on the scale that you'd expect structures** to scale to.
The content you cited acknowledges the premise of the Cosmological Principle, but it does not say anything about what these "reasons" could be.
So, nope, that's not an adequate argument.
Again, I could waste my time on a PhD in Cosmology to come back and actually make a good argument for why homogeneity in structure is favored at large cosmological scales ... but why should I? I didn't bring that particular argument into the conversation [1].
1: https://en.wikipedia.org/wiki/Burden_of_proof_(philosophy)
>So, nope, that's not an adequate argument.
I'm not trying to argue, lol. You're asking for more information but in such a weirdly aggressive way.
The reason there is a soft limit (in our current theories) is because of the cosmological principle
Big lol at the wiki linking of burden of proof. Not every conversation is an argument, holy.
As much as I love HN, this type of aggressiveness and desire to converse as if defending a dissertation can get bloody exhausting.
I'm not trying to argue, lol. You're asking for more information but in such a weirdly aggressive way.
The reason there is a soft limit (in our current theories) is because of the cosmological principle
Big lol at the wiki linking of burden of proof. Not every conversation is an argument, holy.
As much as I love HN, this type of aggressiveness and desire to converse as if defending a dissertation can get bloody exhausting.
>The reason there is a soft limit (in our current theories) is because of the cosmological principle
What? That's a circular argument.
HN is definitely not the place for "me vs. you" grudges, so I stick to making arguments and try to drive the conversation forward, however,
>Have fun! It's quite interesting.
>Unless your goal is to argue, instead of learn, [...]
>Big lol at the wiki linking of burden of proof.
You don't seem to be the one arguing in good faith, though. "You're being aggressive", laughable.
What? That's a circular argument.
HN is definitely not the place for "me vs. you" grudges, so I stick to making arguments and try to drive the conversation forward, however,
>Have fun! It's quite interesting.
>Unless your goal is to argue, instead of learn, [...]
>Big lol at the wiki linking of burden of proof.
You don't seem to be the one arguing in good faith, though. "You're being aggressive", laughable.
My "Have fun!" was genuine, I had a lot of fun learning about this stuff despite not pursuing a PhD in cosmology. Anton Petrov covers this specific topic in a few videos, as well as other large structures, and it's truly fascinating.
The rest was probably a bit uncalled for, you're right. I was immediately put on edge by "Yeah, read the site guidelines, yo." (which, uhh, not sure how that is focused on moving the conversation forward but lets leave it at we were both touchy!)
The rest was probably a bit uncalled for, you're right. I was immediately put on edge by "Yeah, read the site guidelines, yo." (which, uhh, not sure how that is focused on moving the conversation forward but lets leave it at we were both touchy!)
Yes, that is why the scientists did a statistical analysis, otherwise it wouldn't be worthy of publication. From the arXiv paper:
> Using the Convex Hull of Member Spheres (CHMS) algorithm, we estimate that the annulus and inner absorbers of the BR have departures from random expectations, at the density of the control field, of up to 5.2σ.
5 sigma is the gold standard at which we can safely exclude the noise explanation.
> Using the Convex Hull of Member Spheres (CHMS) algorithm, we estimate that the annulus and inner absorbers of the BR have departures from random expectations, at the density of the control field, of up to 5.2σ.
5 sigma is the gold standard at which we can safely exclude the noise explanation.
The artist impression in the article is heavily misleading IMHO. The actual "ring" is much more jagged and looks very similar to all the nearby so called "filaments" they labeled. I'm not sure if it's crossing the threshold from constellation-ism to real astronomy. Download the arXiv paper and see for yourself.
[deleted]
Supposedly if you scan the sky long enough, you'd find a copy of Shakespeare's play written in the stars.
The upper estimate of the number of galaxies in the observable universe is 2 trillion, which is far too few to find Shakespeare written with "galaxy dots".
There are an infinite number of ways to ascribe meaning to galaxy dots such that they would write out Shakespeare.
Can you propose one which doesn't use massive lookup tables?
Writing Shakespeare in English requires a pretty massive look up table - we call it a dictionary.
No, you don't need a massive dictionary. Remember that the topic of this thread is a circle composed of galaxy "dots".
An elongated circle can be the letter O or perhaps zero. You can similarly compose other letters visually using galaxy dots, and that's presumably what the original poster meant when talking about writing out a Shakespeare. If the universe was infinite, this would be a possibility.
An elongated circle can be the letter O or perhaps zero. You can similarly compose other letters visually using galaxy dots, and that's presumably what the original poster meant when talking about writing out a Shakespeare. If the universe was infinite, this would be a possibility.
Why? It's not random.
Yeah, maybe. Certainly a theory. But that artist impression has 24 dots, so the odds of getting a circle might be the same as getting a well drawn rabbit, or a "lol :)" (pencilling it out 24 dots seems reasonable for a "lol :)").
But the fact we got a circle rather than something funny suggests it is probably a phenomenon that causes circles responsible. Circles are far more common in nature than statistics might suggest. Nature well knows circles.
But the fact we got a circle rather than something funny suggests it is probably a phenomenon that causes circles responsible. Circles are far more common in nature than statistics might suggest. Nature well knows circles.
That’s clearly a Cyclops smiley face.
Or a weak wifi signal.
Or a weak wifi signal.
Its a smiley face being drawn in progress.
Pi constant appears again
Strong Expanse vibes
This is obviously cosmic graffiti. Damn kids.
Wait till they find a grouping of galaxies of a phallic shape.
The giant red arc in the image has a certain similarity.
“The Long Man describes what is possibly a collection of three burial mounds, the middle one oblong and the ones to the sides round, quite frankly, in a suggestive arrangement that Nanny Ogg approves of.
If geography could talk, this bit of it would be boasting: the whole landscape saying "I've got a great big tonker"”
Fairy ring.
*The Three-Body Problem intensifies*
Oh give me a locus, where the gravitons focus, and the three-body problem is solved… [1]
1. https://www.youtube.com/watch?v=dRns6u5bHuw
1. https://www.youtube.com/watch?v=dRns6u5bHuw
It's obviously the result of a construction project by a hitherto unknown Type IV civilization on the Kardashev scale. /s
My partner, mocking: “they found heaven!”
I'm not an astronomer either, but pretty sure if I generated uniformly random points on the scale of number of visible galaxys, I could find a circle in there
Pretty sure you wouldn't find many circles containing galaxies all at a similar approximate distance
There might be some, so it could be lucky and just random chance, but the stats seem to say that it's very unlikely
There might be some, so it could be lucky and just random chance, but the stats seem to say that it's very unlikely
> 9.2 billion light-years from Earth
> cosmological neighbours
These structures are more than halfway across the observable Universe. It's ludicrous to claim that they are neighbours.
> cosmological neighbours
These structures are more than halfway across the observable Universe. It's ludicrous to claim that they are neighbours.
They're saying the Big Ring is a neighbor not of earth, but of the "giant arc of galaxies" which "appears in the same region of sky at the same distance from Earth as the Big Ring".
The circle and the arc are cosmological neighbours to one another, not to us.
They are close enough to each other.
They are close enough to each other.
Fair enough; but the article doesn't mention how close together they are. Judging from the diagram, they're separated by an angular distance roughly the same size as the larger structure; so about 3 billion LY.
If you've got two structures of size X, with a distance of X between them as well, that's relatively close.
That's as if Paris had a second Eiffel tower three blocks away.
That's as if Paris had a second Eiffel tower three blocks away.
Yeah, that makes sense if Paris is just 15 blocks across, and the Eiffel Tower is a couple of blocks wide, and there's nothing (observable) outside Paris.
And that doesn't even mean they are really close between them linearly.
https://youtu.be/fwRJGaIcX6A?t=173
Here's an in-depth seminar on the findings of the Giant Arc in the Sky, her work prior to the Big Ring discovery:
https://www.youtube.com/watch?v=-zkGk6EPMC8
She was also featured in a pop-sci BBC Four documentary:
https://www.youtube.com/watch?v=S36MqEzUzIw
Unfortunately all videos are of quite bad quality, but the explanations are a good introduction to the work.