The Great Walls - Largest Structures in the Universe

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Expand view Topic review: The Great Walls - Largest Structures in the Universe

Re: The Great Walls - Largest Structures in the Universe

Post by NamelessGhoul » Thu Jan 31, 2013 1:52 pm

Superclusters of Galaxies & The Great Sloan Wall

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Re: The Great Walls - Largest Structures in the Universe

Post by NamelessGhoul » Thu Jan 31, 2013 1:51 pm

Clusters Of Galaxies - Professor Caroline Crawford

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Clusters of galaxies are the largest organised structures in the Universe that appear gravitationally bound, containing thousands of galaxies all confined to a volume of space only tens of millions of light years across. They are laboratories for extreme galaxy evolution, as many of the processes that can change the structure of galaxies are accelerated in such a crowded environment. Clusters of galaxies also provide important constraints for cosmology: from both the way they are grouped into superclusters that trace the 'large scale structure' of Universe; and the fact that their internal properties lead to powerful confirmation for the need for dark energy.

The transcript and downloadable versions of the lecture are available from the Gresham College website: ... f-galaxies

Re: The Great Walls - Largest Structures in the Universe

Post by NamelessGhoul » Thu Jan 31, 2013 1:36 pm

The Nearest Superclusters

This is a map of the universe within 500 million light years. It shows most of the major galaxy superclusters that surround the Virgo supercluster. These superclusters are not isolated in space but together with many other smaller concentrations of galaxies they form parts of extensive walls of galaxies surrounding large voids. Three of the biggest walls near us are marked on the map as well as several of the largest voids. There are several hundred thousand large galaxies within 500 million light years, so even on this scale our galaxy is a very insignificant object.



Re: The Great Walls - Largest Structures in the Universe

Post by NamelessGhoul » Sat Jan 26, 2013 7:09 pm

Largest Structure in Universe Discovered

Date: 11 January 2013


Astronomers have discovered the largest known structure in the universe, a clump of active galactic cores that stretches 4 billion light-years from end to end.

The structure is a large quasar group (LQG), a collection of extremely luminous galactic nuclei powered by supermassive central black holes. This particular group is so large that it challenges modern cosmological theory, researchers said. "While it is difficult to fathom the scale of this LQG, we can say quite definitely it is the largest structure ever seen in the entire universe," lead author Roger Clowes, of the University of Central Lancashire in England, said in a statement. "This is hugely exciting, not least because it runs counter to our current understanding of the scale of the universe." Quasars are the brightest objects in the universe. For decades, astronomers have known that they tend to assemble in huge groups, some of which are more than 600 million light-years wide. But the record-breaking quasar group, which Clowes and his team spotted in data gathered by the Sloan Digital Sky Survey, is on another scale altogether. The newfound LQC is composed of 73 quasars and spans about 1.6 billion light-years in most directions, though it is 4 billion light-years across at its widest point.

To put that mind-boggling size into perspective, the disk of the Milky Way galaxy — home of Earth's solar system — is about 100,000 light-years wide. And the Milky Way is separated from its nearest galactic neighbor, Andromeda, by about 2.5 million light-years.

The newly discovered LQC is so enormous, in fact, that theory predicts it shouldn't exist, researchers said. The quasar group appears to violate a widely accepted assumption known as the cosmological principle, which holds that the universe is essentially homogeneous when viewed at a sufficiently large scale. Calculations suggest that structures larger than about 1.2 billion light-years should not exist, researchers said. "Our team has been looking at similar cases which add further weight to this challenge, and we will be continuing to investigate these fascinating phenomena," Clowes said.

The new study was published in the Monthly Notices (Jan. 11) of the Royal Astronomical Society.

The Great Walls - Largest Structures in the Universe

Post by NamelessGhoul » Sat Jan 26, 2013 7:02 pm

There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy

The Great Walls - Largest Structures in the Universe

"Just as a fish may be barely aware of the medium in which it lives and swims, so the microstructure of empty space could be far too complex for unaided human brains."


Our known Hubble length universe contains hundreds of millions of galaxies that have clumped together, forming super clusters and a series of massive walls of galaxies separated by vast voids of empty space.

Great Wall: The most vast structure ever is a collection of superclusters a billion light years away extending for 5% the length of the entire observable universe. It is theorized that such structures as the Great Wall form along and follow web-like strings of dark matter that dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts baryonic matter, and it is this normal matter that astronomers see forming long, thin walls of super-galactic clusters. If it took God one week to make the Earth, going by mass it would take him two quintillion years to build this thing -- far longer than science says the universe has existed, and it's kind of fun to have those two the other way around for a change. Though He could always omnipotently cheat and say "Let there be a Sloan Great Wall." The Great Wall is a massive array of astronomical objects named after the observations which revealed them, the Sloan Digital Sky Survey. An eight year project scanned over a quarter of the sky to generate full 3-D maps of almost a million galaxies. Analysis of these images revealed a huge panel of galaxies 1.37 billion light years long, and even the pedantic-sounding .07 is six hundred and sixty billion trillion kilometers. This is science precisely measuring made-up sounding numbers.

Sloane_9: This isn't the only wall out there -- others exist, all with far greater lengths than width or depth, actual sheets of galaxies forming some of the most impressive anythings there are. And these walls are only a special class of galactic filaments, long strings of matter stretched between mind-breaking expanses of emptiness. Some of these elongated super clusters have formed a series of walls, one after another, spaced from 500 million to 800 million light years apart, such that in one direction alone, 13 Great Walls have formed with the inner and outer walls separated by less than seven billion light years. Recently, cosmologists have estimated that some of these galactic walls may have taken from 80 billion to 100 billion, to 150 billion years to form in a direct challenge to current age estimates of the age of the Universe following the Big Bang. The huge Sloan Great Wall spans over one billion light years. The Coma cluster (image above) is one of the largest observed structures in the Universe, containing over 10,000 galaxies and extending more than 1.37 billion light years in length.

Panoramic view of the entire near-infrared sky reveals the distribution of galaxies beyond the Milky Way. Click image to enlarge.

Current theories of "dark energy" and "great attractors" have been developed to explain why a created universe did not spread out uniformly at the same speed and in the same spoke-like directions as predicted by theory. But as Sean Carroll of the Moore Center for Theoretical Cosmology and Physics at Cal Tech is fond of saying, "We don't have a clue." Britain’s Astronomer Royal, Lord Rees, says some of the cosmos’s biggest mysteries, like the Big Bang and even the nature of our own self awareness, might never be resolved. Rees, who is also President of the Royal Society, says that a correct basic theory of the universe might be present, but may be just too tough for human beings’ brains to comprehend.