#Cosmicflow-3

[underzemilkyway]

This Massive Wall of Galaxies Is Lurking Beyond the Milky Way | Seeker - Elements

Cosmographers recently revealed a massive wall of galaxies lurking shockingly close by. But why was it hidden from our view for so long?

Cosmographers’ goal is to map out the observable universe, and from their findings we can not only learn more about the structures that make up everything we can see, we also gain insight into the things we cannot see.

The universe is full of massive structures hidden from our view, like the area of the sky above the South Pole that has been dubbed the “Zone of Avoidance,” in our very own Milky Way.

Some cosmographers pulled out some clever tricks to peer into the Zone of Avoidance. Using a catalog of the motions and distances of 18,000 galaxies called Cosmicflows-3, the scientists noticed that some galaxies were moving faster or slower than expected, and seemed to be drawn to something in the middle, something hidden in the Zone of Avoidance.

Computer models revealed a wall made up of thousands of galaxies at least 600 million light-years deep and 1.4 billion light-years across, forming a bow shape over the southern hemisphere’s sky.

Find out more about the South Pole Wall in this Elements.

[cilginfizikcilervbi]

Karanlık Maddeden Köprüler

Karanlık Maddeden Köprüler Karanlık madde şimdiye kadar görülmemişse de varlığı kesin olarak biliniyor. Bilim insanları yıldız ve galaksilerin hareketlerine göre karanlık maddenin dolaylı olarak nasıl dağılmış olduğunu çıkarabiliyorlar. Seoul Üniversitesi’nden Sungwook Hang karanlık madde üzerine yeni bir yöntem kullandı. Hang yapay zekayı kullanarak galaksilerin, yıldızlararası madde ve…

[astroblogs]

Donkere materie toont de bruggen tussen sterrenstelsels in het lokale kosmische web

Donkere materie toont de bruggen tussen sterrenstelsels in het lokale kosmische web

Het lokale kosmische web in beeld gebracht. X is de plek van het Melkwegstelsel. Credit: Hong et al/Astrophysical Journal. Een internationaal team van sterrenkundigen is er in geslaagd om de verdeling van donkere materie in de omgeving van het Melkwegstelsel in kaart te brengen en om daarmee de bruggen van (donkere) materie te tonen tussen de sterrenstelsels in het lokale kosmische web. Het…

[adrianusv61]

Donkere materie toont de bruggen tussen sterrenstelsels in het lokale kosmische web

Donkere materie toont de bruggen tussen sterrenstelsels in het lokale kosmische web

Het lokale kosmische web in beeld gebracht. X is de plek van het Melkwegstelsel. Credit: Hong et al/Astrophysical Journal. Een internationaal team van sterrenkundigen is er in geslaagd om de verdeling van donkere materie in de omgeving van het Melkwegstelsel in kaart te brengen en om daarmee de bruggen van (donkere) materie te tonen tussen de sterrenstelsels in het lokale kosmische web. Het…

[pharaoh-mindset]

🤔You must learn a new way to think💭 before you can master a new way to be🤴🏾👸🏾,,,,Trust the process, be patient because it's when nothing happens that anything can happen💯🙌🏾👊🏾 👑👽🖖🏾 💫 ☯️🙌🏾🎰🕉️ #1111 #3 #vibescalledblessed #loveyourself #woke #staywoke #universe #intuition #thirdeye #asé #starseed #1111portal #spiritguide #balance #manifestation #universecalling #nobadvibes #cosmicflow #transformation https://www.instagram.com/p/Bs0nysBh_w4/?utm_source=ig_tumblr_share&igshid=1a8s9uy94wtmp

[apod]

2019 August 6

The Local Void in the Nearby Universe Image Credit: R. Brent Tully (U. Hawaii) et al.

Explanation: What does our region of the Universe look like? Since galaxies are so spread out over the sky, and since our Milky Way Galaxy blocks part of the distant sky, it has been hard to tell. A new map has been made, however, using large-scale galaxy motions to infer what massive objects must be gravitating in the nearby universe. The featured map, spanning over 600 million light years on a side, shows that our Milky Way Galaxy is on the edge of the Virgo Cluster of Galaxies, which is connected to the Great Attractor -- an even larger grouping of galaxies. Also nearby are the massive Coma Cluster and the extensive Perseus-Pisces Supercluster. Conversely, we are also on the edge of huge region nearly empty of galaxies known as the Local Void. The repulsive push by the Local Void combined with the gravitational pull toward the elevated galaxy density on the other side of the sky explains part of the mysteriously high speed our Galaxy has relative to the cosmic microwave background -- but not all. To explore the local universe yourself, as determined by Cosmicflows-3, you are invited to zoom in and spin around this interactive 3D visualization.

∞ Source: apod.nasa.gov/apod/ap190806.html

[urrepules]

The Local Void in the Nearby Universe

Image Credit:

R. Brent Tully (U. Hawaii) et al.

Explanation: What does our region of the Universe look like? Since galaxies are so spread out over the sky, and since our Milky Way Galaxy blocks part of the distant sky, it has been hard to tell. A new map has been made, however, using large-scale galaxy motions to infer what massive objects must be gravitating in the nearby universe. The featured map, spanning over 600 million light years on a side, shows that our Milky Way Galaxy is on the edge of the Virgo Cluster of Galaxies, which is connected to the Great Attractor -- an even larger grouping of galaxies. Also nearby are the massive Coma Cluster and the extensive Perseus-Pisces Supercluster. Conversely, we are also on the edge of huge region nearly empty of galaxies known as the Local Void. The repulsive push by the Local Void combined with the gravitational pull toward the elevated galaxy density on the other side of the sky explains part of the mysteriously high speed our Galaxy has relative to the cosmic microwave background -- but not all. To explore the local universe yourself, as determined by Cosmicflows-3, you are invited to zoom in and spin around this interactive 3D visualization.

via Astronomy Picture of the Day (APOD)

[kapuzenhemd-blog]

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http://www.bing.com/images/search?q=science+fiction+klassiker+bücher

http://www.bing.com/images/search?q=science+fiction  

http://www.bing.com/images/search?q=flug+scheibe

http://www.bing.com/images/search?q=raum+schiff

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https://www.tor-online.de/feature/buch/2019/03/die-100-besten-science-fiction-buecher-aller-zeiten

Die 100 besten Science-Fiction-Bücher (a..z)

Als es noch Menschen gab - Clifford Simak (City, 1952)

Andymon - Angela und Karlheinz Steinmüller (1982)

Auf zwei Planeten - Kurd Laßwitz (1897)

Auslöschung - Jeff VanderMeer (Annihilation, 2014)

Bedenke Phlebas - Iain M. Banks (Consider Phlebas, 1987)

Binti - Nnedi Okorafor (2015)

Blade Runner (Träumen Androide von elektrischen Schafen) - Philip K. Dick (Do Androids Dream Of Electric Sheep, 1968)

Blumen für Algernon - Daniel Keyes (Flowers for Algernon, 1966)

Der brennende Mann (Die Rache des Kosmonauten, Tiger! Tiger!) - Alfred Bester (The Stars My Destination, 1956)

Commander Perkins - H. G. Francis (1979, Hörspiele 1976)

Contact - Carl Sagan (1985)

Cyberabad - Ian McDonald (River of Gods, 2004)

Dämmerung - Octavia Butler (Dawn, 1987)

Dangerous Visions - Hrsg. Harlan Ellison (1967)

Die denkenden Wälder - Alan Dean Foster (Midworld, 1979)

Dhalgren - Samuel R. Delany (1975)

Doktor Ain - James Tiptree jr.

A Door Into Ocean – Joan Slonczewski

Die Drachenreiter von Pern - Anne McCaffrey (Dragonriders of Pern, 1977 - 2012)

Die drei Sonnen - Cixin Liu (三體 / 三体, 2008)

Die Ehen zwischen den Zonen Drei, Vier und Fünf - Doris Lessing (The Marriages Between Zones Three, Four and Five, 1980)

Ein Junge und sein Hund - Harlan Ellison (A Boy and His Dog, 1969)

Einsatz der Waffen - Iain M. Banks (Use of Weapons, 1990)

Enders Spiel - Orson Scott Card (Ender’s Game, 1985)

Es stirbt in mir - Robert Silverberg (Dying Inside, 1972)

Evolution - Stephen Baxter (2003)

Der ewige Krieg - Joe Haldeman (The Forever War, 1974)

Expanse-Reihe - James A. Corey (2011 - )

Fahrenheit 451 - Ray Bradbury (1953)

Frankenstein oder Der moderne Prometheus - Mary Shelley (Frankenstein or The Modern Prometheus, 2018)

Foundation-Trilogie - Isaac Asimov (Foundation, 1951)

Die Frau des Zeitreisenden - Audrey Niffenegger (The Time Traveler's Wife, 2003)

Freie Geister (Planet der Habenichtse, Die Enteigneten) Ursula K. Le Guin (The Dispossessed, 1974)

Fremder in einer fremden Welt - Robert Heinlein (Stranger in a Strange Land, 1961)

Der futurologische Kongress - Stanislaw Lem (Kongres futurologiczny, 1971)

Gateway - Frederik Pohl (1977)

Gelb - Jeff Noon (Vurt, 1993)

Die Haarteppichknüpfer - Andreas Eschbach (1995)

Hardboiled Wonderland und das Ende der Welt - Haruke Murakami (Sekai No owari to Hādoboirudo Wandārando, 1985

Herland - Charlotte Perkins Gilman (1915)

Hier sangen einst Vögel - Kate Wilhelm (Where Late the Sweet Birds Sang, 1976)

Die Hölle ist die Abwesenheit Gottes - Ted Chiang

Hyperion - Dan Simmons (1989)

Ich, der Robot - Isaac Asimov (I Robot, 1950)

Der illustrierte Mann - Ray Bradbury (The illustrated Man, 1951)

Die Insel des Dr. Moreau - H. G. Wells (The Island of Dr. Moreau, 1869)

Kinder der Zeit - Adrian Tchaikovsky (Children of Time, 2015)

Krieg der Klone - John Scalzi (Old Man’s War, 2005)

Krieg der Welten - H. G. Wells (The War of the Worlds, 1898)

Krieg mit dem Molchen - Karel Čapeks (Válka s mloky, 1936)

Die lange Erde - Stephen Baxter und Terry Pratchett (The Long Earth, 2012)

Der lange Weg zu einem kleinen, zornigen Planeten - Becky Chambers (The Long Way to a Small, Angry Planet, 2015)

Die Letzten der Menschheit – Walter Tevis (Mockingbird, 1980)

Der letzte Tag der Schöpfung - Wolfgang Jeschke

Liebe ist der Plan - James Tiptree jr.

Die linke Hand der Dunkelheit (Der Winterplanet) - (The Left Hand Of Darkness, 1969)

Little Brother - Cory Doctorow (2008)

Die Mars-Chroniken - Ray Bardbury (The Martian Chronicles, 1950)

Der Marsianer - Andy Weir (The Martian - 2001)

Die Mars-Trilogie (Roter Mars, Blauer Mars, Grüner Mars) - Kim Stanley Robinson (Red Mars, Blue Mars, Green Mars, 1992 - 1996)

Die Maschinen - Anne Leckie (Ancillary Justice, 2013)

Metro 2033 - Dmitri Glukhovsky (2007)

Der Mond ist eine herbe Geliebte (Revolte auf Luna, Mondpsuren) - Robert Heinlein (The Moon Is a Harsh Mistress, 1966)

Morgenwelt - John Brunner (Stand on Zansibar, 1968)

Nachspiel-Trilogie (Star Wars) - Chuck Wendig (Aftermath 2015 - 2017)

Neuromancer - William Gibson (1984)

Das Orakel vom Berge - Philip K. Dick (The Man in The High Castle, 1962)

Otherland von Tad Williams

Per Anhalter durch die Galaxis - Douglas Adams (The Hitchhiker's Guide to the Galaxy, 1979)

Perdito Street Station (Die Falter/Der Weber) - China Miéville (2000)

Perry Rhodan - Clark Dalton

Picknick am Wegesrand - Arkadi und Boris Strugatzki (Piknik na obotschinje, 1972)

Die Reise zum Mittelpunkt der Erde - Jules Verne (Voyage au centre de la terre, 1864)

Rendezvous mit Rama - Arthur C. Clark (Rendezvous with Rama, 1973)

Der Report der Magd - Margaret Atwood (The Handmaid’s Tale, 1985)

Ringwelt - Larry Niven (Ringworld, 1970)

Schöne neue Welt - Aldous Huxley (Brave New World, 1932)

Schlachthof 5 oder Der Kinderkreuzzug - Kurt Vonnegut (Slaughterhouse-Five, or The Children's Crusade: A Duty-Dance with Death, 1969)

Simulacron-3 - Daniel F. Galouye (1963)

Snow Crash - Neal Stephenson (1992)

Solaris - Stanislaw Lem (1961)

Spin - Robert Charles Wilson - (2005)

Der Splitter im Auge Gottes - Larry Niven und Jerry Pournelle (The Mote in God's Eye, 1974)

Starship Troopers (Sternenkrieger) - Robert Heinlein (1959)

Die Triffids - John Wyndham (The Day of the Triffids, 1951)

Ubik - Philip K. Dick (1969)

Uhrwerk Orange - Anthony Burgess (Clockwork Orange, 1962)

Das Unsterblichkeitsprogramm - Richard Morgan (Altered Carbon, 2002)

Utopia - Thomas Morus (De optimo rei publicae statu deque nova insula Utopia, 1516)

Die vergessene Welt - Arthur Conan Doyle

Was aus den Menschen wurde - Cordwainer Smith (2011, umfasst Kurzgeschichten von 1928 bis 1966)

Wer fürchtet den Tod - Nnedi Okorafor (Who Fears Death, 2010)

Wir waren außer uns vor Glück – David Marusek

Das Wort für Welt ist Wald - Ursula K. Le Guin (The Word For World Is Forest, 1972)

Der Wüstenplanet von Frank Herbert (Dune, 1965)

Die Zeitmaschine - H. G. Wells (The Time Machine, 1895)

Zerrissene Erde - N. K. Jemisin (The Fifth Season. 2015)

1984 - George Orwell (1949)

2001 - Arthur C. Clark (1968)

20.000 Meilen unter dem Meer - Jules Verne (Vingt mille lieues sous les mers, 1869)

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https://www.amazon.de/Science-Fiction-Bücher/s?k=Science+Fiction

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national radio quiet zone

https://science.nrao.edu/facilities/gbt/interference-protection/nrqz

http://www.landesmuseum.at/de/ausstellungen/detail/paul-kranzler-andrew-phelps-es-war-einmal-in-amerika.html

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void

https://en.wikipedia.org/wiki/Local_Void

Cosmicflows-3: Cosmography of the Local Void    [] https://arxiv.org/abs/1905.08329

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https://twitter.com/ESA     #     https://sci.esa.int/web/juice/home/

[sciencespies]

New dark matter map shows the bridges between the Milky Way and nearby galaxies

https://sciencespies.com/space/new-dark-matter-map-shows-the-bridges-between-the-milky-way-and-nearby-galaxies/

New dark matter map shows the bridges between the Milky Way and nearby galaxies

A new map of dark matter made using artificial intelligence reveals hidden filaments of the invisible stuff bridging galaxies.

The map focuses on the local universe — the neighborhood surrounding the Milky Way. Despite being close by, the local universe is difficult to map because it’s chock full of complex structures made of visible matter, said Donghui Jeong, an astrophysicist at Pennsylvania State University and the lead author of the new research. 

“We have to reverse engineer to know where dark matter is by looking at galaxies,” Jeong told Live Science.

Related: The 11 biggest unanswered questions about dark matter

Dark matter is a mysterious, invisible substance that interacts with visible matter via gravity.

Some researchers theorize that this invisible matter might consist of weakly interacting massive particles, or WIMPs, which would be very large (for subatomic particles, anyway) and electromagnetically neutral, so that they wouldn’t interact with anything on the electromagnetic spectrum, such as light.

Another idea with some potential evidence to back it up is that dark matter might consist of ultralight particles called axions.

Whatever dark matter is, its effects are detectable in the gravitational forces permeating the universe.

Mapping out an invisible gravitational force isn’t easy, though.

Typically, researchers do it by running large computer simulations, starting with a model of the early universe and fast-forwarding through billions of years of expansion and evolution of visible matter, filling in the gravitational blanks to figure out where dark matter was and where it should be today. This requires major computing power and significant amounts of time, Jeong said.

This new study takes a different approach. The researchers first trained a machine-learning program on thousands of computer simulations of visible matter and dark matter in the local universe.

Machine learning is a technique that is particularly adept at picking out patterns from large datasets. The model universes in the study came from a sophisticated set of simulations called Illustris-TNG.

After testing the machine-learning algorithm’s training on a second set of Illustris-TNG universe simulations for accuracy, the researchers applied it to real-world data.

They used the Cosmicflows-3 galaxy catalog, which holds data on the distribution and movement of the visible matter within 200 megaparsecs, or 6.5 billion light-years, of the Milky Way. That area includes more than 17,000 galaxies.

(Hong et. al., Astrophysical Journal, 2021)

Above: These density maps – each a cross-section in different dimensions –reproduce known, prominent features of the universe (red) and also reveal smaller filamentary features (yellow) that act as hidden bridges between galaxies. The X denotes the Milky Way galaxy and arrows denote the motion of the local universe due to gravity.

The result was a new map of dark matter in the local universe and its relationships to visible matter.

In a promising finding, the machine-learning algorithm reproduced much of what was already known or suspected about the Milky Way’s neighborhood from cosmological simulations.

But it also suggested new features, including long filaments of dark matter that connect galaxies around the Milky Way to it and to one another. 

This is important for understanding how galaxies will move over time, Jeong said.

For example, the Milky Way and the Andromeda galaxies are expected to crash into each other in about 4.5 billion years.

Understanding local dark matter’s role in that collision could help address more precisely how and when that merger – and others – will occur.

“Now that we know the distribution of dark matter we can calculate more accurately the acceleration that will move the galaxies around us,” Jeong said. 

The research appeared May 26 in the Astrophysical Journal.

Related content:

6 ways the hunt for dark matter has changed

The 11 biggest unanswered questions about dark matter

The 18 biggest unsolved mysteries in physics 

This article was originally published by Live Science. Read the original article here.

#Space

[netexecindia]

The Local Void in the Nearby Universe August 06, 2019 via NASA What does our region of the Universe look like? Since galaxies are so spread out over the sky, and since our Milky Way Galaxy blocks part of the distant sky, it has been hard to tell. A new map has been made, however, using large-scale galaxy motions to infer what massive objects must be gravitating in the nearby universe. The featured map, spanning over 600 million light years on a side, shows that our Milky Way Galaxy is on the edge of the Virgo Cluster of Galaxies, which is connected to the Great Attractor -- an even larger grouping of galaxies. Also nearby are the massive Coma Cluster and the extensive Perseus-Pisces Supercluster. Conversely, we are also on the edge of huge region nearly empty of galaxies known as the Local Void. The repulsive push by the Local Void combined with the gravitational pull toward the elevated galaxy density on the other side of the sky explains part of the mysteriously high speed our Galaxy has relative to the cosmic microwave background -- but not all. To explore the local universe yourself, as determined by Cosmicflows-3, you are invited to zoom in and spin around this interactive 3D visualization. #NASA https://go.nasa.gov/2ZyHQJe

[krrw2020]

The Local Void in the Nearby Universe

What does our region of the Universe look like? Since galaxies are so spread out over the sky, and since our Milky Way Galaxy blocks part of the distant sky, it has been hard to tell. A new map has been made, however, using large-scale galaxy motions to infer what massive objects must be gravitating in the nearby universe. The featured map, spanning over 600 million light years on a side, shows that our Milky Way Galaxy is on the edge of the Virgo Cluster of Galaxies, which is connected to the Great Attractor -- an even larger grouping of galaxies. Also nearby are the massive Coma Cluster and the extensive Perseus-Pisces Supercluster. Conversely, we are also on the edge of huge region nearly empty of galaxies known as the Local Void. The repulsive push by the Local Void combined with the gravitational pull toward the elevated galaxy density on the other side of the sky explains part of the mysteriously high speed our Galaxy has relative to the cosmic microwave background -- but not all. To explore the local universe yourself, as determined by Cosmicflows-3, you are invited to zoom in and spin around this interactive 3D visualization. August 06, 2019 from NASA | https://apod.nasa.gov/apod/ap190806.html

[whyisthenightsosad]

The Local Void in the Nearby Universe

What does our region of the Universe look like? Since galaxies are so spread out over the sky, and since our Milky Way Galaxy blocks part of the distant sky, it has been hard to tell. A new map has been made, however, using large-scale galaxy motions to infer what massive objects must be gravitating in the nearby universe. The featured map, spanning over 600 million light years on a side, shows that our Milky Way Galaxy is on the edge of the Virgo Cluster of Galaxies, which is connected to the Great Attractor -- an even larger grouping of galaxies. Also nearby are the massive Coma Cluster and the extensive Perseus-Pisces Supercluster. Conversely, we are also on the edge of huge region nearly empty of galaxies known as the Local Void. The repulsive push by the Local Void combined with the gravitational pull toward the elevated galaxy density on the other side of the sky explains part of the mysteriously high speed our Galaxy has relative to the cosmic microwave background -- but not all. To explore the local universe yourself, as determined by Cosmicflows-3, you are invited to zoom in and spin around this interactive 3D visualization. August 06, 2019 from NASA https://ift.tt/2OFsXDX via IFTTT

[arko006-blog]

Intergalactic wall: Stretch of galaxies some 1.4 bn light-years long discovered in the universe- Technology News, Firstpost

Intergalactic wall: Stretch of galaxies some 1.4 bn light-years long discovered in the universe- Technology News, Firstpost

[ad_1]

FP TrendingJul 15, 2020 10:12:43 IST

Scientists have found an intergalactic “wall” of galaxies that’s at least 1.4 billion light-years long. It is considered as one of the largest structures in the known universe.

The study published in The Astrophysical Journal tells about the discovery of the South Pole Wall, which is a structure that stretches across the southern border of the…

[shirlleycoyle]

Scientists Discovered a Gigantic Structure in a Hidden Zone of Space

Scientists have spotted a gargantuan bow-like structure made of galaxies that stretches for 1.4 billion light years across the skies above the South Pole.

This “South Pole Wall” is one of the biggest structures ever glimpsed by humans, and its discovery was announced in a study published on Friday in The Astrophysical Journal.

“When our visualizations indicated something going on at the celestial South Pole, we were surprised: indeed there were no reports of a large scale structure in this region,” said Daniel Pomarède, a cosmographer at Paris-Saclay University in France who led the new study, in an email.

The South Pole Wall is comparable in size to the Sloan Great Wall, the sixth-largest known structure in the universe, though the South Pole Wall is located about 500 million light years from Earth, twice as close as the Sloan structure.

The universe contains many of these enormous belts that connect objects in space to a fundamental matrix known as the cosmic web. Galaxies tend to cluster at the crossroads of these long filaments, which are made of hydrogen gas and a mysterious non-luminous substance called dark matter. The largest known structure is the Hercules-Corona Borealis Great Wall, which is 10 billion light years wide—equal to about a tenth of the diameter of the entire observable universe.

The South Pole Wall is not quite that big, but it is the largest structure ever spotted within a radius of about 650 millions light years around Earth, according to Pomarède. The crooked shape of the structure enabled the team to detect the wall’s extent, relative to a straight-line structure, because so much of it fit within the observational aperture.

“It is because it is shaped like a bow that its 1.4 billion light-years length can fit the observed sphere,” Pomarède explained, though he added that the map the team used “fades away just beyond the wall.”

“So, perhaps we are not seeing the whole of it, if it happens to bend away from us beyond our observational limit,” he said.

You might think that it would be hard to miss a filament as colossal as the South Pole Wall, given that it appears to be some 14,000 times longer than the diameter of our galaxy, the Milky Way, and contains thousands of galaxies within its boundaries. It is so big, in fact, that if it were to magically get outlined in the night sky, like a celestial chalk drawing, skywatchers on Earth would not be able to see it all from one hemisphere.

However, this particular structure is located in the “Zone of Avoidance,” which is the region of space right behind the dusty center of the Milky Way from our perspective on Earth. As a result, our galaxy’s bulk has blocked it from view—until now.

The discovery occurred when Pomarède and his colleagues noticed that the gravitational influence of some gigantic structure was pulling galaxies towards it in all directions.

Pomarède and his colleagues used Cosmicflows-3, a comprehensive catalog that visualizes the distances and motions of 18,000 galaxies, to indirectly peer at the knots and filaments that make up the cosmic web. One of the team’s main goals—and a major quest for astronomers in general—is to figure out how the gravitational heft of the web’s large-scale structures influences the motions of galaxies, including our own Milky Way.

Decades of research has revealed that the Local Group, a cluster of galaxies that includes the Milky Way, is moving at about 630 kilometers per second, at least in part due to gravitational attraction from large-scale structures as well as repulsion from empty regions of space known as voids.

The Cosmicflows-3 map recorded peculiar velocities of galaxies on one side of the obscured South Pole Wall that seemed slower than expected, while galaxies on the side closer to Earth moved a bit faster than expected.

“Our study told us that the South Pole Wall, due to its gravitational attraction, is acting upon us, giving us a velocity of about 40 km/s,” Pomarède said. “We would like to know whether other structures are contributing: in particular, is there something hidden in the Zone of Avoidance? There might be filaments crossing this zone. We are looking for them.”

Following those breadcrumbs, the researchers were able to reconstruct some of the South Pole Wall using models and algorithms, though they said they will not be sure of its full size until more detailed versions of Cosmicflows become available in the coming years. In other words, the South Pole Wall may be much larger than its current estimated dimensions of 1.4 billion light years across, and some 600 million light years deep, but we would need a bigger map to know for sure.

“Our scientific discipline is called cosmography, a branch of cosmology, that aims at establishing a cartography of the cosmos around us (our local universe),” Pomarède said. “Like cartographers who mapped Earth, we map the structure of the sky, and thus we learn more about the structures we live in, and we study whether what we find is compatible with the current theory of structure formation (in the context of the standard model of cosmology).”

Finding one of the top-ten biggest structures in the universe is pretty wild by itself, but these discoveries also reveal threads of the larger cosmic tapestry that undergirds our surroundings and reality. The more we learn about these elongated bubbles filled with dark matter and galaxies, the more we will understand how we came to live in this weird and ever-evolving universe.

Scientists Discovered a Gigantic Structure in a Hidden Zone of Space syndicated from https://triviaqaweb.wordpress.com/feed/

[gozealouscloudcollection]

天文學家構建“本地空洞”的3D模型 併計算出其對銀河系的引力影響

就像地球圍繞著太陽公轉和太陽運行圍繞著銀河系中心公轉一樣，我們的銀河系本身正以極快的速度穿越宇宙。銀河係以及附近的鄰居如仙女星系和一系列較小的星系，以時速約為200萬公里/小時（130萬英里/小時）的速度高速移動。

這種差異可以通過在巨大尺度上的質量分佈來解釋。星係不是均勻地分佈在整個宇宙中 – 它們傾向於聚集成星系團，通過“細微細絲”材料像蜘蛛網這樣連接起來。這使得大部分空間相對空洞 – 正如天文學家在1987年發現的那樣，銀河係正好位於其中一個邊緣。

眾所周知，這個所謂的本地空洞（Local Void）是位於本星系群旁邊，這個幾乎空無一物的空間似乎正變得越來越大。幾年前，天文學家發現，被稱為Dipole Repeller 的特低密度的區域正在推動銀河系和本星系牆(Local Sheet)中的其他星系- 這是一個幾乎平坦的星系團，構成了空洞的“一道牆”。

但是本地空洞很難研究。對於這項新研究，該團隊測量了一個名為Cosmicflows-3的數據集，其中詳細描述了18000個星系的運動。利用這一點，研究人員構建了一張三維宇宙地圖，發現本地空洞的“牆”成為焦點。

該團隊還利用這些信息計算了本地空洞對我們銀河系施加的引力影響。在考慮到宇宙膨脹後的預期速度後，研究人員發現，我們星系團大約一半的運動是“本地”產生的，因為巨大的室女座星系團將銀河系拉向它並且本地空洞將銀河系“驅離”。

這項新研究發表在《天體物理學雜誌》上。該團隊在下面的視頻中詳細介紹了使用本地空洞3D模型的形狀和結構。

.(tagsToTranslate)科學探索(t)天文學家構建“本地空洞”的3D模型 併計算出其對銀河系的引力影響(t)kknews.xyz from 天文學家構建“本地空洞”的3D模型 併計算出其對銀河系的引力影響 via KKNEWS

[sciencespies]

A giant 'wall' of galaxies has been found stretching across the Universe

https://sciencespies.com/space/a-giant-wall-of-galaxies-has-been-found-stretching-across-the-universe/

A giant 'wall' of galaxies has been found stretching across the Universe

The Universe isn’t just a random scattering of galaxies sprinkled throughout an expanding void. The closer we look, the more we see that there are structures – some of which are incomprehensibly vast groupings and clusters of galaxies that are gravitationally bound together.

Such a structure has just been discovered arcing across the southern edge of the sky, and it’s a colossus, spanning an immense 1.37 billion light-years from end to end. Its discoverers have named it the South Pole Wall.

Although the size is remarkable – it’s one of the largest structures in space we’ve ever seen – we know exactly what the South Pole Wall is. It’s a galaxy filament, a huge formation of galaxies that forms a border between the empty spaces of cosmic voids that together form the cosmic web. Hence, we call it a wall.

Other, larger such walls are known. The largest is the Hercules-Corona Borealis Great Wall, which spans 9.7 billion light-years. But the South Pole Wall is special, because it’s insanely close to the Milky Way galaxy, lying just 500 million light-years away. In other words, it is the most massive structure we’ve ever seen this close.

You’re probably wondering how on Laniakea we managed to miss one of the largest galaxy filaments in the Universe right on our doorstep. And there’s actually a really good answer to that question: it was hidden behind what astronomers sometimes call the Zone of Avoidance or Zone of Galactic Obscuration – the Milky Way galactic plane.

This is the disc of our home galaxy, a region thick and bright with dust and gas and stars. So thick and bright, in fact, that it obscures a large part of what’s behind it, making that region of the Universe poorly explored compared to the rest.

If this Zone of Avoidance hid the South Pole Wall so effectively, how have astronomers found it now? The answer to that question is a little more complex, but basically, it hinges on how galaxies move around the sky.

A team of researchers led by cosmographer Daniel Pomarède of the Paris-Saclay University used a database called Cosmicflows-3, which contains distance calculations to nearly 18,000 galaxies. These are figured out using redshift, which measures how rapidly something is moving farther away based on how stretched out its light waves are.

Last year, a different team of researchers used this database to calculate another parameter, something known as peculiar velocity, which is the velocity of a galaxy relative to its motion due to the expansion of the Universe.

With these two parameters, the team could calculate the motions of the galaxies relative to each other – and these motions revealed the gravitational influence of a much larger mass. With the help of algorithms, the team was able to use these motions to map in three dimensions the distribution of material in the South Pole Wall, even beyond the Zone of Avoidance.

(Pomarède et al., ApJ, 2020)

The densest section lies over the South Pole – this part is the section that’s 500 million light-years away. Then it curves north and towards us, coming within 300 million light-years of the Milky Way.

Along the curving arm, the galaxies are moving towards the clump at the South Pole; and from there, they are moving towards another giant structure, the Shapley Supercluster 650 million light-years away.

Because there are parts of the South Pole Wall we can’t see, it’s possible that the structure is even larger than we can tell at this point. But we can be sure that astronomers are itching to find out.

For one, it could have interesting cosmological implications, affecting the rate of expansion of the local Universe. This may or may not play a role in the Hubble Tension, the difference between the rate of expansion in the local Universe and the rate of expansion in the early Universe.

It can also help us understand the evolution of our local corner of space, which includes Laniakea, the supercluster of galaxies to which the Milky Way belongs, also discovered by Pomarède and his colleagues (led by Brent Tully of the University of Hawai’i at Manoa) back in 2014.

This is a magnificent discovery, and we can’t wait to see what else it will reveal.

The research has been published in The Astrophysical Journal.

#Space