Astronomy

How many galaxies are there in the Hercules-Corona Borealis Great Wall?

How many galaxies are there in the Hercules-Corona Borealis Great Wall?



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The Hercules-Corona Borealis Great Wall is "to date (February 16, 2015), it is the largest and the most massive structure known in the observable universe" (source). How many galaxies is the Hercules-Corona Borealis Great Wall believed to contain?


I'm sorry for the long answer. The result is in the bottom. :)

The number of galaxies in the "wall", as in any volume of space, is the number density $n_{mathrm{gal}}$ times its volume $V_{mathrm{wall}}$. However, the number density of galaxies depends on their masses/sizes: Small galaxies are much more common than large galaxies. Usually we describe this by the halo mass function (HMF), which gives the (differential) number density dN/dM of dark matter halos hosting galaxies as a function of halo mass M. Depending on your favorite cosmology, it looks something like this (created with this tool):

The solid line shows the HMF today in the local Universe, i.e. at redshift zero, while the dashed and dotted line shows how it was at redshift 1.6 and 2.1, respectively, roughly 10 billion years ago, which mark the beginning and end of the wall (according to Horváth et al. 2014, A&A, 561, L12). Notice how the number of large halos grow with time, at the expense of small halos. This is due to the smaller ones accreting onto larger ones.

The HMFs are characterized by a power law at low masses with an exponential cut-off at high masses. To get the total number density we need to integrate over the entire range of masses, and here comes the problem: Whereas the upper limit is set by the maximum size a galaxy can have (roughly $3 imes10^{13}M_odot$, but the exact number isn't very important, as these galaxies are so rare), the lower limit depends on your definition of a galaxy. Large galaxies have smaller galaxies orbiting as satellites, and there isn't a well-defined threshold for when a clump of gas, stars, and dark matter is called a galaxy. These guys report on the detection of a $sim10^3M_odot$ clump which they call a galaxy. That's probably not what you think of as a galaxy, so for the sake of this exercise, let's use Small Magellanic Cloud-sized galaxies as our lower minimum, i.e $sim 6.5 imes10^9 M_odot$.

The total number density of galaxies is thus found by integrating the HMF. Luckily, the online HMF tool can do that as well. The result, i.e. the number density of halos above a given mass, looks like this:

Note that the $x$ axis is given in terms of $h^{-1}M_odot$. Since $h simeq 0.7$, the mass of the SMC is $M_mathrm{SMC} simeq 5 imes10^9 h^{-1}M_odot$. From the graph, the number density of these objects is $sim0.5,h^3mathrm{Mpc}^{-3} = 0.17,mathrm{Mpc}^{-3}$ (1 Mpc, or megaparsec, equals 3.26 million lightyears). In principle we should subtract the number density of halos above $3 imes10^{13}M_odot$, but since these are four orders of magnitude smaller, they can be neglected.

The wall starts at redshift ~1.6 and ends at redshift ~2.1. This translates into starting at a distance of 4.65 Gpc (billion parsec) and ending at 5.47 Gpc, i.e. a depth of ~800 Mpc. These numbers are in comoving coordinates, i.e. what it has expanded to today, as opposed to physical coordinates, i.e. what it was at the time it emitted the light that we see today. But the HMF is given in terms of comoving volume, so that's cool.

To get the volume, we also need the area. The finders report that it's roughly 2 Gpc times 3 Gpc, but they don't seem to state whether this is in physical or comoving coordinates (which differ by a factor (1+z) ~ 3). I suspect it's comoving, though.

Thus, the total volume is $V_{mathrm{wall}} = 0.8 imes 2 imes 3,mathrm{Gpc}^3 = 4.8,mathrm{Gpc}^3 = 4.8 imes10^9,mathrm{Mpc}^3$, or 166 cubic gigalightyears. Here, I have ignored the fact that the physical area spanned by the angle of observation is a bit different at the front and the back of the wall, but since these numbers are already quite uncertain, it's of lesser importance.

The considerations above are all for the average Universe. But the wall represents an overdensity in space, so the number will be larger. I can't find any estimates of the overdensity of this particular supercluster, but in general galaxies in superclusters are more numerous by a factor of $delta sim 5$-$10$. Let's use 5.

That is, the total number of galaxies the size of the Small Magellanic Cloud or above is $$N_mathrm{gal,tot} = n_mathrm{gal} imes V_mathrm{wall} imes delta$$ $$= 0.17,mathrm{Mpc}^{-3} imes 4.8 imes10^9,mathrm{Mpc}^3 imes 5$$ $$sim 4 mathrm{,billion,galaxies}.$$

But if you go through the same exercise for halos of masses above, say, $10^3,M_odot$, you'll find a number which is a million times larger.

In reality, the number density of luminous galaxies is smaller. At the high-mass end, the gas has trouble cooling sufficiently to condense and create stars, and active galactic nuclei in massive galaxies heat the gas. At the low-mass end, gas is more easily blown out of the potential well by stellar feedback from supernovae.


Hercules–Corona Borealis Great Wall

The Hercules–Corona Borealis Great Wall is the largest known super-structure in the universe.

It is a huge group of galaxies forming a giant sheet-like pattern which is about 10 billion light-years long, 7.2 billion light-years wide, and almost 1 billion light-years thick. It is about 10 billion light-years away in the constellations of Hercules and Corona Borealis, hence its name.

It was discovered in November 2013 by mapping gamma-ray bursts. [1] They are very luminous explosions of distant, massive stars, the most powerful explosions in the universe. A typical burst releases more energy in less than a tenth of a second than the Sun will in its whole life of 10 billion years.

Gamma-ray bursts are very rare: only one happens in a typical galaxy every few million years. The stars which cause these explosions are very massive, so the material required for them to be formed must be in great amounts. So, these explosions can be used to track down if there is a galaxy in that direction, or there is a large group of matter in there.

Between the years of 1997 to 2012, astronomers mapped these bursts in the sky, with the help of the robotic satellites Swift and Fermi which looks for gamma-ray bursts and measures their redshifts. In the map they produced, they noticed something interesting 14 gamma-ray bursts have very similar redshifts and are very close to each other. This means that there is a very large group of galaxies and matter in the region. They say, from measuring these bursts, comes up with a very large structure measuring 10 billion light-years in diameter.

For comparison, the Milky Way, the galaxy we live in, measures only 200,000 light-years, and the distance from the Milky Way to the Andromeda Galaxy measures only 2.5 million light-years. The Huge-LQG (the Huge Large Quasar Group), the previous largest structure in the universe, is 4 billion light-years long.

The discovery of the Hercules–Corona Borealis Great Wall contradicts a theory proposed by Albert Einstein known as the cosmological principle. The cosmological principle says that the entire universe is approximately equal any two regions in the universe will look very similar, even if those two regions are very far apart, assuming those regions have sizes larger than 250 to 300 million light-years. Maximum sizes of structures must be around 1.2 billion light-years based on the meaning above, and no structure must be larger than that, assuming that matter is spreaded equally from the Big Bang. However, the structure, is eight times larger than the limit, contradicting the cosmological principle.

The structure also contradicts theories about the evolution of the universe. The structure is 10 billion light-years away, which means that we see the structure 10 billion years ago, when the universe is only 13.8 billion years old, and its light was just approaching us. The 3.8 billion year span of time is too short for a giant structure 10 billion light-years long to form. Even Istvan Horvath, the discoverer of the structure, says he has no idea how the structure has formed in that amount of time. For now, the existence of the structure is still a mystery for cosmologists.

Another idea says that the idea of the Big Bang might be proven false as a result of this incredible cosmic structure


The Biggest Thing In The Universe Is So Gigantic It Shouldn't Exist At All (VIDEO)

Astronomers used to think it was a "filament" of galaxies known as the Sloan Great Wall. But recent research suggests a different structure is even bigger -- and its size has astronomers scratching their heads.

Meet the Hercules-Corona Borealis Great Wall (Her-CrB GW). Check it out in the video above.

"The Her-CrB GW is larger than the theoretical upper limit on how big universal structures can be," Dr. Jon Hakkila, an astrophysics professor at the College of Charleston in South Carolina and one of the astronomers who discovered the structure, told The Huffington Post in an email. "Thus, it is a conundrum: it shouldn't exist but apparently does."

Mysteries just like this are why astronomers scan the skies for a glimpse into the past, as they shed light not only on the early years of our universe, but also more about our galaxy, our solar system, and ultimately, ourselves.

"We are now mapping structures across the sky," astronomer Dr. Jay M. Pasachoff, director of the Hopkins Observatory at Williams College in Williamstown, Mass., who was not involved in the great wall's discovery, told The Huffington Post. "We’re learning how the universe grew up. So we’re learning about how our cluster of galaxies grew up and how our own galaxy grew up and how our sun formed, and how the Earth formed soon there after. We’re looking back at our history."

Because astronomers are still mapping the sky, there just may be something even grander than the Hercules-Corona Borealis Great Wall in our universe.

"The danger of finding the biggest, or most distant, or the oldest things in the universe is always that sooner or later someone is likely to come along and find something bigger, more distant, or older than the thing you found," Hakkila said. "So far we have not been upstaged, but it has only been about six months since we published."

The finding was published in the journal Astronomy & Astrophysics.

What’s the biggest thing in the universe? That sounds like a simple question, but the answer is strangely complicated and recently there’s been evidence that the object that we thought was biggest really isn’t.

Hey everyone. Jacqueline Howard here. So, the Earth is pretty big, but you know it’s nowhere near the biggest thing in the observable universe. The sun is way bigger--in fact, you could fit a million Earths inside it--but it’s tiny compared to some of the other stars in our galaxy. And we know that our galaxy, the Milky Way, is just one of 200 billion galaxies in our universe and many of the others are much bigger than ours. But even the biggest galaxies out there are pipsqueaks compared to some other structures that astronomers have found.

For years, astronomers were convinced that a structure known as the Sloan Great Wall was the biggest-known structure in the universe. This vast cluster of galaxies and other cosmic matter is a mind-boggling 1.4 billion light-years across. But just recently they found something even bigger.

Feast your eyes on the Hercules-Corona Borealis Great Wall measuring around 10 billion light-years across. How big is that exactly? In miles that’s a six followed by like 22 zeros. And if you’re going at the speed of light, it would take you 10 billion years to get from one end to the other. Sheesh. So this just may be the largest and most massive structure in the observable universe -- and its very existence has left astronomers scratching their heads.

You see, this ‘great wall’ is so massively ginormous that it shouldn’t even exist, given the age of the universe. Astronomers just can’t wrap their heads around the idea that an object that formed only a few billion years after the Big Bang could have grown so big.

So there you have it. The biggest structure in the universe is the Hercules-Corona Borealis Great Wall--at least for now. How great is that?


FREE AstroScience

The Hercules–Corona Borealis Great Wall is the largest known super-structure in the universe.
It is a huge group of galaxies forming a giant sheet-like pattern which is about 10 billion light-years long (for perspective, the observable universe is about 93 billion light years in diameter), 7.2 billion light-years wide, and almost 1 billion light-years thick. It is about 10 billion light-years away in the constellations of Hercules and Corona Borealis, hence its name.

It was discovered in November 2013 by mapping gamma-ray bursts. They are very luminous explosions of distant, massive stars, the most powerful explosions in the universe. A typical burst releases more energy in less than a tenth of a second than the Sun will in its whole life of 10 billion years.

Gamma-ray bursts are very rare: only one happens in a typical galaxy every few million years. The stars which cause these explosions are very massive, so the material required for them to be formed must be in great amounts. So, these explosions can be used to track down if there is a galaxy in that direction, or there is a large group of matter in there.

Between the years of 1997 to 2012, astronomers mapped these bursts in the sky, with the help of the robotic satellites Swift and Fermi which looks for gamma-ray bursts and measures their redshifts. In the map they produced, they noticed something interesting 14 gamma-ray bursts have very similar redshifts and are very close to each other. This means that there is a very large group of galaxies and matter in the region. They say, from measuring these bursts, comes up with a very large structure measuring 10 billion light-years in diameter.

For comparison, the Milky Way, the galaxy we live in, measures only 200,000 light-years, and the distance from the Milky Way to the Andromeda Galaxy measures only 2.5 million light-years. The Huge-LQG (the Huge Large Quasar Group), the previous largest structure in the universe, is 4 billion light-years long.

The discovery of the Hercules–Corona Borealis Great Wall contradicts a theory proposed by Albert Einstein known as the cosmological principle. The cosmological principle says that the entire universe is approximately equal any two regions in the universe will look very similar, even if those two regions are very far apart, assuming those regions have sizes larger than 250 to 300 million light-years.

Maximum sizes of structures must be around 1.2 billion light-years based on the meaning above, and no structure must be larger than that, assuming that matter is spreaded equally from the Big Bang. However, the structure, is eight times larger than the limit, contradicting the cosmological principle.

The structure also contradicts theories about the evolution of the universe. The structure is 10 billion light-years away, which means that we see the structure 10 billion years ago, when the universe is only 13.8 billion years old, and its light was just approaching us.

The 3.8 billion year span of time is too short for a giant structure 10 billion light-years long to form. Even Istvan Horvath, the discoverer of the structure, says he has no idea how the structure has formed in that amount of time. For now, the existence of the structure is still a mystery for cosmologists.

Another idea says that the idea of the Big Bang might be proven false as a result of this incredible cosmic structure.


Astronomers discover huge galactic wall hidden behind Milky Way

FOX NEWS - Scientists have discovered a celestial structure made of galaxies more than 1.4 billion light-years long and 600 million light-years deep in the skies over the South Pole, according to a report.

The South Pole Wall, as it has been dubbed, is situated along the southern border of the cosmos from the perspective of Earth, and consists of thousands of galaxies, hydrogen gas, dust and dark matter, Vice and MIT Technology Review explains. It&aposs also one of the largest known structures in the universe.

The wall is among a number of structures that make up the cosmic web, including the Great Wall, the Bootes Void, the comparably sized Sloan Great Wall and the Hercules Corona-Borealis Great Wall, the largest known structure at 10 billion light-years wide, according to MIT.

That’s about a tenth of the diameter of the observable universe, Vice reported.

The findings were first announced last Friday in the Astrophysical Journal.

The South Pole Wall, however, is half the distance from the Earth to the Hercules Corona-Borealis Great Wall – 500 million light-years – and was hidden by the brightness of the Milky Way in an area called the Zone of Avoidance, according to MIT.

It was discovered when scientists saw galaxies in different directions around it were affected by its gravitational pull.

The wall is the largest structure discovered within a 650 million light-year radius from Earth, according to Vice.

“When our visualizations indicated something going on at the celestial South Pole, we were surprised,” Paris-Saclay University in France cosmographer Daniel Pomar, told Vice in an email. “Indeed, there were no reports of a large scale structure in this region.”

Pomar told Vice that the wall’s bow-like makeup is the reason its “length can fit the observed sphere,” adding the map the scientists used �s away just beyond the wall. So, perhaps we are not seeing the whole of it, if it happens to bend away from us beyond our observational limit.”


Intergalactic wall: Stretch of galaxies some 1.4 bn light-years long discovered in the universe

FP Trending Jul 15, 2020 10:12:43 IST

Scientists have found an intergalactic “wall” of galaxies that’s at least 1.4 billion light-years long. It is considered as one of the largest structures in the known universe.

The study published in The Astrophysical Journal tells about the discovery of the South Pole Wall, which is a structure that stretches across the southern border of the universe.

The structure comprises thousands of galaxies and huge amounts of gas and dust.

According to MIT Technology Review, galaxies aren’t just spread randomly throughout the universe. Rather, they collect into larger groupings of massive filaments, which are separated by giant voids of nearly empty space. These filaments are basically a wall of galaxies that stretch for hundreds of millions of light-years.

Astronomers have found one of the largest structures in the known universe—a wall of galaxies. Image: MIT Review

There are similar, known walls in the universe like the South Pole Wall, including the Great Wall, the Sloan Great Wall, the Hercules-Corona Borealis Great Wall, and the Bootes Void.

What makes the South Pole Wall especially interesting is that it is close to the Milky Way galaxy, lying just 500 million light-years away, ScienceAlert reported. It is the most massive structure scientists have ever seen this close to our own Milky Way galaxy.

The researchers also discovered one of the largest galaxy filaments near our galaxy quite late, hidden behind what the Zone of Avoidance or Zone of Galactic Obscuration, reported ScienceAlert. This region in the southern part of the sky is so brightly light by the Milky Way that it blocks out much of what's behind or around it.

The study was carried out by a team of researchers led by cosmographer Daniel Pomarède of the Paris-Saclay University. They used a database called Cosmicflows-3 containing distance calculations to nearly 18,000 galaxies.

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Largest thing in the universe: Hercules-Corona Borealis Great Wall

By mapping the locations of gamma-ray bursts &mdash fleeting but powerful explosions that occur when a massive star dies &mdash astronomers uncovered what is often considered to be the largest known entity in the cosmos: the Hercules-Corona Borealis Great Wall. The object is 10 billion light-years across and could contain billions of galaxies. The Great Wall was first discovered in 2013 when surveys showed gamma-rays particularly concentrated about 10 billion light-years away in the direction of the Hercules and Corona Borealis constellations.


Hercules–Corona Borealis Great Wall

The Hercules–Corona Borealis Great Wall is the largest known super-structure in the universe.

It is a huge group of galaxies forming a giant sheet-like pattern which is about 10 billion light-years long, 7.2 billion light-years wide, and almost 1 billion light-years thick. It is about 10 billion light-years away in the constellations of Hercules and Corona Borealis, hence its name.

It was discovered in November 2013 by mapping gamma-ray bursts. [1] They are very luminous explosions of distant, massive stars, the most powerful explosions in the universe. A typical burst releases more energy in less than a tenth of a second than the Sun will in its whole life of 10 billion years.

Gamma-ray bursts are very rare: only one happens in a typical galaxy every few million years. The stars which cause these explosions are very massive, so the material required for them to be formed must be in great amounts. So, these explosions can be used to track down if there is a galaxy in that direction, or there is a large group of matter in there.

Between the years of 1997 to 2012, astronomers mapped these bursts in the sky, with the help of the robotic satellites Swift and Fermi which looks for gamma-ray bursts and measures their redshifts. In the map they produced, they noticed something interesting 14 gamma-ray bursts have very similar redshifts and are very close to each other. This means that there is a very large group of galaxies and matter in the region. They say, from measuring these bursts, comes up with a very large structure measuring 10 billion light-years in diameter.

For comparison, the Milky Way, the galaxy we live in, measures only 200,000 light-years, and the distance from the Milky Way to the Andromeda Galaxy measures only 2.5 million light-years. The Huge-LQG (the Huge Large Quasar Group), the previous largest structure in the universe, is 4 billion light-years long.

The discovery of the Hercules–Corona Borealis Great Wall contradicts a theory proposed by Albert Einstein known as the cosmological principle. The cosmological principle says that the entire universe is approximately equal any two regions in the universe will look very similar, even if those two regions are very far apart, assuming those regions have sizes larger than 250 to 300 million light-years. Maximum sizes of structures must be around 1.2 billion light-years based on the meaning above, and no structure must be larger than that, assuming that matter is spreaded equally from the Big Bang. However, the structure, is eight times larger than the limit, contradicting the cosmological principle.

The structure also contradicts theories about the evolution of the universe. The structure is 10 billion light-years away, which means that we see the structure 10 billion years ago, when the universe is only 13.8 billion years old, and its light was just approaching us. The 3.8 billion year span of time is too short for a giant structure 10 billion light-years long to form. Even Istvan Horvath, the discoverer of the structure, says he has no idea how the structure has formed in that amount of time. For now, the existence of the structure is still a mystery for cosmologists.

Another idea says that the idea of the Big Bang might be proven false as a result of this incredible cosmic structure


Astronomers discover South Pole Wall, a gigantic structure stretching 1.4 billion light-years across

Spectacular 3D maps of the universe have revealed one of the biggest cosmic structures ever found — an almost-inconceivable wall stretching 1.4 billion light-years across that contains hundreds of thousands of galaxies.

The South Pole Wall, as it's been dubbed, has been hiding in plain sight, remaining undetected until now because large parts of it sit half a billion light-years away behind the bright Milky Way galaxy. The South Pole Wall rivals in size the Sloan Great Wall, the sixth largest cosmic structure discovered. (One light-year is roughly 6 trillion miles, or 9 trillion kilometers, so this "biggest cosmic structure" is mind-bendingly humongous.)

Astronomers have long noticed that galaxies are not scattered randomly throughout the universe but rather clump together in what's known as the cosmic web, enormous strands of hydrogen gas in which galaxies are strung like pearls on a necklace that surround gigantic and largely empty voids.

Mapping these intergalactic threads belongs to the field of cosmography, which is "the cartography of the cosmos," study researcher Daniel Pomarede, a cosmographer at Paris-Saclay University in France, told Live Science.

Previous cosmographic work has charted the extent of other galactic assemblies, such as the current structural record holder, the Hercules-Corona Borealis Great Wall, which spans 10 billion light-years, or more than a tenth the size of the visible universe.

In 2014, Pomarede and his colleagues unveiled the Laniakea supercluster, a galactic collection in which our own Milky Way resides. Lanaikea is 520 million light-years wide and contains roughly the mass of 100 million billion suns.

For their new map, the team used newly-created sky surveys to peer into a region called the Zone of Galactic Obscuration. This is an area in the southern part of the sky in which the bright light of the Milky Way blocks out much of what's behind and around it.

Cosmographers typically determine the distance to objects using redshift, the speed at which an object is receding from Earth due to the expansion of the universe, which depends on their distance, Pomarede said. The farther away an object is, the faster it will appear to be receding from Earth, an observation first made by astronomer Edwin Hubble in 1929 and which has held up ever since.

But he and his colleagues used a slightly different technique, looking at the peculiar velocity of galaxies. This measurement includes redshift but also takes into account the motion of galaxies around one another as they tug at each other gravitationally, Pomarede said.

The advantage of the method is that it can detect hidden mass that is gravitationally influencing how galaxies move and therefore uncover dark matter, that invisible stuff that emits no light but exerts a gravitational tug on anything near enough. (Dark matter also makes up the bulk of the matter in the universe.) By running algorithms looking at peculiar motion in galactic catalogs, the team was able to plot the three-dimensional distribution of matter in and around the Zone of Galactic Obscuration. Their findings are detailed today (July 9) in The Astrophysical Journal.

The resulting map shows a mind-boggling bubble of material more or less centered on the southernmost point of the sky, with a great sweeping wing extending north on one side in the direction of the constellation Cetus and another stubbier arm opposite it in the direction of the constellation Apus.

Knowing how the universe looks on such large scales helps confirm our current cosmological models, Neta Bahcall, an astrophysicist at Princeton University in New Jersey who was not involved in the work, told Live Science. But determining where exactly these enormous, crisscrossing structures begin and end is tricky, she added.

"When you look at the network of filaments and voids, it becomes a semantic question of what's connected," she said.

In their paper, the team acknowledges that they may not have plotted yet the entirety of the vast South Pole Wall. "We will not be certain of its full extent, nor whether it is unusual, until we map the universe on a significantly grander scale," they wrote.


Biggest Structures of the Universe

Astronomers discovered one of the largest structures in the known universe – a giant wall of galaxies of about 1.4 billion light years long. Considering how close this massive structure is to us, it is remarkable that we never noticed it before.

For the past ten years, an international team of astronomers led by Brent Tully from the University of Hawaii’s Institute for Astronomy, has been mapping the distribution of galaxies around the Milky Way. Astronomers dubbed this newly-defined structure “The South Pole Wall”, which lies beyond Laniakea, a huge supercluster of galaxies including our own.

Galaxies are not just distributed randomly in the universe. Instead, they are grouped into large filaments separated by giant voids of space. Each filament is basically a wall of galaxies stretching across hundreds of millions of light years. These are the largest structures in the known universe. Outside, there are regions consisting almost entirely of emptiness. Other similar structures identified to date include the Great Wall, Sloan Great Wall, Hercules-Corona Borealis Great Wall, and Boötes Void.

However, the newly discovered South Pole Wall is special because it is very close to the Milky Way galaxy, only 500 million light years away. But, how did we not notice such a massive structure so close to us? It was hidden behind the Milky Way galactic plane, sometimes called by the astronomers as the Zone of Avoidance or Zone of Galactic Obscuration. It is almost impossible to observe anything behind this region, which is the disc of our home galaxy, so thick and bright with dust and gas and stars that it obscures everything else.

The team behind the discovery of the South Pole Wall made redshift observations on galaxies as part of their research in the sky, while also adding in their peculiar velocity values – the velocity of a galaxy relative to its motion due to the expansion of the Universe. This technique allows astronomers to spot otherwise unseen masses. Using this data, researchers were able to map the South Pole Wall.

The South Pole Wall curves the region like an arm, just beyond the Laniakea Supercluster. The busiest part lies in the direction of the Earth’s South Pole, inspiring its name. It draws a large arc of 200 degrees, extending into the northern sky. Since there are parts of it we cannot see, the South Pole Wall is likely larger than we can say at this point.


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