Astronomers have discovered that there is a vast wall across the southern border of the local cosmos.
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. It is so massive that it perturbs the local expansion of the universe.
But don’t bother trying to see it. The entire conglomeration is behind the Milky Way, in what astronomers quaintly call the zone of avoidance.
An international team of astronomers led by Daniel Pomarède of Paris-Saclay University and R. Brent Tully of the University of Hawaii announced this new addition to the local universe on Friday in a paper in Astrophysical Journal. 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.
It is the latest installment of an ongoing mission to determine where we are in the universe — to fix our neighborhood among the galaxies and the endless voids — and where we are going.
“The surprise for us is that this structure is as big as the Sloan Great Wall and twice as close, and remained unnoticed, being hidden in an obscured sector of the southern sky,” Dr. Pomarède said in an email.
“The discovery is a wonderful poster child for the power of visualizations in research,” Dr. Tully said.
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.
The new paper was based on measurements, performed by Dr. Tully and his colleagues, of the distances of 18,000 galaxies as far away as 600 million light-years. By comparison, the most distant objects we can see — quasars and galaxies that formed shortly after the Big Bang — are about 13 billion light years away.
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One astonishing aspect of the wall is how big it is compared to the volume that the team was surveying: a contiguous filament of light 1.4 billion light-years long, packed into a cloud maybe 600 million in radius. “There is hardly room in the volume for anything bigger!” Dr. Tully said in an email. “We’d have to anticipate that our view of the filament is clipped; that it extends beyond our survey horizon.”
And yet the South Pole Wall is nearby in cosmological terms. “One might wonder how such a large and not-so-distant structure remained unnoticed,” Dr. Pomarède mused in a statement issued by his university.
But in the expanding universe, there is always something more to see.
https://www.nytimes.com/2020/07/10/science/astronomy-galaxies-attractor-universe.html
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. It is so massive that it perturbs the local expansion of the universe.
But don’t bother trying to see it. The entire conglomeration is behind the Milky Way, in what astronomers quaintly call the zone of avoidance.
An international team of astronomers led by Daniel Pomarède of Paris-Saclay University and R. Brent Tully of the University of Hawaii announced this new addition to the local universe on Friday in a paper in Astrophysical Journal. 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.
It is the latest installment of an ongoing mission to determine where we are in the universe — to fix our neighborhood among the galaxies and the endless voids — and where we are going.
“The surprise for us is that this structure is as big as the Sloan Great Wall and twice as close, and remained unnoticed, being hidden in an obscured sector of the southern sky,” Dr. Pomarède said in an email.
“The discovery is a wonderful poster child for the power of visualizations in research,” Dr. Tully said.
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.
The new paper was based on measurements, performed by Dr. Tully and his colleagues, of the distances of 18,000 galaxies as far away as 600 million light-years. By comparison, the most distant objects we can see — quasars and galaxies that formed shortly after the Big Bang — are about 13 billion light years away.
A computer model of the South Pole Wall, with denser areas of matter displayed in red. The entire region shown spans about 1.3 billion light-years; our Milky Way galaxy, barely 100,000 light-years across, is located in the center of the image, where the red and blue arrows originateCredit...Daniel Pomarède
The galaxies in the wall cannot be seen, but Dr. Pomarède and his colleagues were able to observe their gravitational effects by assembling data from telescopes around the world....
One astonishing aspect of the wall is how big it is compared to the volume that the team was surveying: a contiguous filament of light 1.4 billion light-years long, packed into a cloud maybe 600 million in radius. “There is hardly room in the volume for anything bigger!” Dr. Tully said in an email. “We’d have to anticipate that our view of the filament is clipped; that it extends beyond our survey horizon.”
And yet the South Pole Wall is nearby in cosmological terms. “One might wonder how such a large and not-so-distant structure remained unnoticed,” Dr. Pomarède mused in a statement issued by his university.
But in the expanding universe, there is always something more to see.
https://www.nytimes.com/2020/07/10/science/astronomy-galaxies-attractor-universe.html
