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Galactic wall discovered outside the Milky Way

Astronomers recently discovered that behind the MilkyAlong the way, there is a huge wall of thousands of galaxies - clumps of trillions of stars and worlds, as well as dust and gas, lined up in a curtain that traverses at least 700 million light-years of space. It winds behind the dust, gas and stars of our own galaxy from the constellation Perseus in the Northern Hemisphere to the constellation Apus in the Southern Hemisphere. This wall is so massive that it outrages the local expansion of the Universe, but it is impossible to see it, since this entire star cluster is located right behind our home galaxy. Astronomers call this area the Zone of Avoidance.

It looks like the stellar core of the Milky Way galaxyin infrared light. Image captured by NASA's Spitzer Space Telescope. Behind it lies the South Pole Wall, a curtain of thousands of galaxies spanning at least 700 million light years.

Zone of avoidance - the region in the sky, covered by the Milky Way galaxy. Originally called the "Zone of Few Nebulae".

What is a galactic wall?

According to an article published in The New YorkThe Times, an international group of astronomers led by Daniel Pomared of the University of Paris-Saclay and R. Brent Tully of the University of Hawaii, published the results of the new study in the Astrophysical Journal. The work contains maps and diagrams of the features of our local Universe, as well as a video tour of the South Pole wall.

This work is the last part of the ongoingmission, the main goal of which is to discover our place in the universe. In the end, we must know our galactic neighbors and endless voids in person, because it is thanks to them that we can understand where we are going. The discovery is especially remarkable, since the discovered giant star cluster went unnoticed all this time. But what exactly did the scientists manage to find out?

As it turned out, the new wall unites manyother cosmographic features: the location of galaxies or their absence, which researchers have learned about over the past few decades. The study is based on measurements of distances from 18,000 galaxies to 600 million light years. For comparison, the most distant objects that we can see - these are quasars and galaxies formed shortly after the Big Bang - are at a distance from us about 13 billion light years.

Computer model of the South Pole wall, with moredense areas of matter, displayed in red. The entire area shown is about 1.3 billion light-years; the Milky Way galaxy, barely 100,000 light years across, is located in the center of the image

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In an expanding universe, distant galaxiesmove away from us, just like points on an inflating balloon; the further they are, the faster they move away from us, according to the ratio called Hubble law... This movement from the Earth makes the light fromgalaxies shift towards longer, redder wavelengths and lower frequencies, like receding ambulance sirens. By measuring the distances between galaxies, the researchers were able to distinguish motion caused by cosmic expansion from motion caused by gravitational irregularities.

As a result, astronomers discovered that galaxiesbetween the Earth and the South Pole wall are moving away from us a little faster than they should. And the galaxies behind the wall are moving slower than they should be, held back by the walls' gravitational drag. And yet, cosmologically, the South Pole Wall is nearby. One may wonder how such a large and not so distant structure remained unnoticed all these years, but there is always something to see in the expanding universe.

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Cosmic voids

Cosmologists claim that in the largestscale, the universe should expand smoothly, and galaxies should be evenly distributed. But on a smaller, more local scale, the universe looks bumpy and twisted. Scientists have found that galaxies gather, often in the thousands, into giant clouds called clusters, and that they are linked together in laced, luminous chains and strands to form superclusters that span billions of light years. But between them are vast deserts of darkness, called voids.

South Pole wall projection. The plane of the Milky Way is shown in shades of gray on the map; what lies behind the Wall is hidden from direct observation.

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One way or another, our planet is in the Solarsystem, which is located in the Milky Way galaxy. The Milky Way, in turn, is part of a small cluster of galaxies called the Local Group of Galaxies, which sits at the edge of the Virgo Cluster, a conglomerate of several thousand galaxies. In 2014, researchers suggested that all of these features are interconnected, like part of a giant conglomerate that he called Laniakea. For more information on what Laniakeya and galactic voids are, read our material.

In 1986, a group of astronomers discovered thatgalaxies in a huge strip of sky in the direction of the constellation Centaurus are flying away much faster than Hubble's law predicted - as if they are drawn to something that astronomers call The Great Attractor.