Spectacular 3D maps of the universe have revealed one of the largest cosmic structures ever found – an almost unimaginable wall that spans 1.4 billion light years and contains hundreds of thousands of galaxies.
The South Pole wall, as it was called, has been hidden in sight and has so far remained undetected because large parts of it are half a billion light years away behind the bright Milky Way. The south pole wall can compete with the Sloan Great Wall. the sixth largest cosmic structure discovered. (A light year is about 6 trillion miles or 9 trillion kilometers long, so this “largest cosmic structure” is tremendously massive.)
Astronomers have long noticed that galaxies are not randomly scattered throughout the universe, but clump together in what is known as the cosmic networkenormous strands of hydrogen Gas in which galaxies are strung like pearls on a necklace that surrounds gigantic and largely empty cavities.
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Mapping these intergalactic threads is part of the field of cosmography, the “cartography of the cosmos”
Previous cosmographic work has mapped the scale 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 lives. Lanaikea is 520 million light years wide and contains approximately the mass of 100 million billion suns.
For their new map, the team used newly created sky surveys to look into a region called Zone of Galactic Obscuration. This is an area in the southern part of the sky where the bright light of the Milky Way blocks much of what is behind and around it.
Cosmographers usually determine the distance to objects using the red shift, the speed at which an object retracts earth Because of the expansion of the universe, which depends on its distance, Pomarede said. The farther away an object is, the faster it appears to be withdrawing from Earth, an observation first made by Astronomer Edwin Hubble in 1929 and that has persisted ever since.
But he and his colleagues used a slightly different technique to study the peculiar speed of galaxies. This measurement includes redshift, but also takes into account the movement of galaxies around each other when they pull together due to gravity, said Pomarede.
The advantage of the method is that it can detect hidden masses that influence the movement of the galaxies due to gravity, thus revealing dark matter, invisible material that does not emit light, but exerts a gravitational pull on everything that is close enough. (Dark matter also makes up most of the matter in the universe.) By running algorithms that deal with special movements in galactic catalogs, the team was able to represent the three-dimensional distribution of matter in and around the zone of galactic obfuscation. Your results will be detailed in today (July 9th) The Astrophysical Journal.
The resulting map shows a stunning material bubble, more or less centered on the southernmost point of the sky, with a large wing that extends north on one side towards the constellation Cetus, and another more stubborn arm opposite towards the constellation Apus .
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Knowing what the universe looks like on a large scale confirms our current cosmological models, Neta Bahcall, an astrophysicist at Princeton University in New Jersey who was not involved in the work, told Live Science. However, it is difficult to determine exactly where these huge intersecting structures begin and end, she added.
“When you look at the network of filaments and voids, it becomes a semantic question of what is connected,” she said.
In their work, the team admits that they may not have planned the entire giant South Pole wall yet. “We will not be sure if it is fully available or if it is unusual until we map the universe on a much larger scale,” they wrote.
Originally published on Live Science.