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Beyond the Milky Way, a Galactic Wall - The New York Times
Jul 10, 2020 2 mins, 48 secs

The South Pole Wall, as it is known, consists of thousands of galaxies — beehives of trillions of stars and dark worlds, as well as dust and gas — aligned in a curtain arcing across at least 700 million light-years of space.

It winds behind the dust, gas and stars of our own galaxy, the Milky Way, from the constellation Perseus in the Northern Hemisphere to the constellation Apus in the far south.

The paper is festooned with maps and diagrams of blobby and stringy features of our local universe as well as a video tour of the South Pole Wall.

The new wall joins a host of other cosmographic features: arrangements of galaxies, or a lack of them, that astronomers have come to know and love over the last few decades, with names like the Great Wall, the Sloan Great Wall, the Hercules-Corona Borealis Great Wall and the Bootes Void.

In the expanding universe, as described in 1929 by the astronomer Edwin Hubble and confirmed for almost a century, distant galaxies are flying away from us as if they were dots on an inflating balloon; the farther they are, the faster they recede from us, according to a relation called the Hubble law.

As a result, they found that the galaxies between Earth and the South Pole Wall are sailing away from us slightly faster than they otherwise should be, by about 30 miles per second, drawn outward by the enormous blob of matter in the wall.

And yet the South Pole Wall is nearby in cosmological terms.

Astronomers have found that galaxies are gathered, often by the thousands, in giant clouds called clusters and that these are connected to one another in lacy, luminous chains and filaments to form superclusters extending across billions of light-years.

From all of this has emerged what some astronomers call our “long address”: We live on Earth, which is in the solar system, which is in the Milky Way galaxy.

The Milky Way is part of a small cluster of galaxies called the Local Group, which is on the edge of the Virgo cluster, a conglomeration of several thousand galaxies.

In 1986, a group of astronomers who called themselves the Seven Samurai announced that the galaxies in a huge swath of the sky in the direction of the constellation Centaurus were flying away much faster than the Hubble law predicted, as if being pulled toward something — something the astronomers called the Great Attractor.

Subsequent observations revealed that this bath is not uniform: It is slightly warmer in one direction, suggesting that we — Earth, our galaxy and the Local Group — are moving through the microwaves, like a goldfish in a fishbowl, at about 400 miles per second in the approximate direction of Centaurus, but aiming far beyond.

“The South Pole Wall also contributes but, again, only in part,” he added, listing more local galaxy clusters and voids.

Nobody knows exactly what dark matter is made of, but according to cosmologists it provides the gravitational scaffolding for the luminous structures in the universe — galaxies, galaxy clusters, superclusters, voids and chains like the South Pole Wall, all connected by spidery filaments in what’s known as the cosmic web

The visible universe of stars and galaxies, cosmologists like to say, is like snow on mountaintops or lights on dark, distant Christmas trees

But by following the lights and how they are moving, astronomers like Dr

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