APOD: The Local Void in the Nearby Universe (2019 Aug 06)

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APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by APOD Robot » Tue Aug 06, 2019 4:30 am

Image The Local Void in the Nearby Universe

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.

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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by Boomer12k » Tue Aug 06, 2019 9:40 am

Awesome....Supercluster Space....
We seem to be on the edge of the void as well as the Virgo Cluster...

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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by orin stepanek » Tue Aug 06, 2019 12:37 pm

Wheee! Spun it around! :mrgreen: There's a lot of complexities there; shows the author did a lot of work here! Also that the universe is one intriguing SOB! I don't think I'll ever understand it! :shock: The more we learn; the more there is to learn!
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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by Psnarf » Tue Aug 06, 2019 3:03 pm

The repulsive push by the Local Void...
In the quantum world, there is no such thing as "empty" space. Experiments seem to verify the Casimir Effect. Particles mysteriously appear and annihilate. Does all this teeming activity account for the repulsive push by the void? Nuclei contain Higgs bosons which deform the local Higgs field generating an attractive force. Does a lack of such bosons cause the Higgs field to deform in the opposite direction creating a repulsive force? I have rather poor brains to understand how a region of space devoid of galaxies creates a repulsive push. Is there an anti-gravity force? :?:

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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by Psnarf » Tue Aug 06, 2019 3:17 pm

D'oh! I forgot about expansion. Folks posit that empty space expands at about 16km/s/Mpc, To explain the evacuation motion of 260km/s, the very empty Void must be some 45 Mpc across. Phew! Thought I had to get smart on a new force. As to why expansion exists, like Mueller said, it is beyond our purview. Heck, we don't even know what an electron is. :oops:

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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by orin stepanek » Tue Aug 06, 2019 3:51 pm

Psnarf wrote:
Tue Aug 06, 2019 3:17 pm
D'oh! I forgot about expansion. Folks posit that empty space expands at about 16km/s/Mpc, To explain the evacuation motion of 260km/s, the very empty Void must be some 45 Mpc across. Phew! Thought I had to get smart on a new force. As to why expansion exists, like Mueller said, it is beyond our purview. Heck, we don't even know what an electron is. :oops:
Hang onto a hot wire and you can feel them! :mrgreen:
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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by BDanielMayfield » Tue Aug 06, 2019 4:03 pm

Psnarf wrote:
Tue Aug 06, 2019 3:03 pm
The repulsive push by the Local Void...
In the quantum world, there is no such thing as "empty" space. Experiments seem to verify the Casimir Effect. Particles mysteriously appear and annihilate. Does all this teeming activity account for the repulsive push by the void? Nuclei contain Higgs bosons which deform the local Higgs field generating an attractive force. Does a lack of such bosons cause the Higgs field to deform in the opposite direction creating a repulsive force? I have rather poor brains to understand how a region of space devoid of galaxies creates a repulsive push. Is there an anti-gravity force? :?:
Psnarf wrote:
Tue Aug 06, 2019 3:17 pm
D'oh! I forgot about expansion. Folks posit that empty space expands at about 16km/s/Mpc, To explain the evacuation motion of 260km/s, the very empty Void must be some 45 Mpc across. Phew! Thought I had to get smart on a new force. As to why expansion exists, like Mueller said, it is beyond our purview. Heck, we don't even know what an electron is. :oops:
Being able to read your thoughts on 'the repulsive push of the void' was helpful Psnarf. I'm coming to a mental picture of a spongelike expanding universe in which the bubbles (voids) expand but without compression of the material between the voids. But as to what is pumping up the voids, well maybe there is some unknown new force responsible for what's called dark energy.

Just some observations on where we (in this case, all dwellers of the Local Group of galaxies) are in the big scheme of things: It is good to be out on the edge of a galactic supercluster, rather than deeply imbedded inside one. It gives us a better vantage point for being able to see the big picture of the much wider universe. Also, there are survival advantages to being widely removed from more crowded locales.

It is as if we are living on the shoreline of a vast, unexplored supercontinent...

Bruce
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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by ta152h0 » Tue Aug 06, 2019 5:12 pm

I believe the Universe always existed, at absolute 0, and the Big Bang was a fuse that started the visible Universe. pass the ice cold one
Last edited by ta152h0 on Tue Aug 06, 2019 6:22 pm, edited 1 time in total.
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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by neufer » Tue Aug 06, 2019 6:15 pm

ta152h0 wrote:
Tue Aug 06, 2019 5:12 pm

I believe the Universe always existed and the Big Bang was a fuse that started the visible Universe.
pass the ice cold one
You're obviously con-fused from too many brew-skis.
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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by ta152h0 » Tue Aug 06, 2019 11:13 pm

You are likely correct Sir, but this is a place to get schooled.
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IfA: Astronomers Map Vast Void in Our Cosmic Neighborhood

Post by bystander » Tue Aug 13, 2019 4:21 pm

Astronomers Map Vast Void in Our Cosmic Neighborhood
Institute for Astronomy | University of Hawaii | 2019 Jul 22

Cosmicflows-3: Cosmography of the Local Void ~ R Brent Tully et al


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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by sillyworm 2 » Sun Aug 18, 2019 12:37 pm

Thanks bystander..this video of the voids is quite fascinating.This is but a teaspoon of the entire universe?

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Re: APOD: The Local Void in the Nearby Universe (2019 Aug 06)

Post by Psnarf » Sat Aug 24, 2019 5:46 pm

A lot of people of the Buddhist mind-training flavor who escaped from Tibet use names for large periods of time such as kalpas. One kalpa is the time between two big bangs. They posit infinite kalpas of universes coming into being from causes and conditions, arising, existing, then ceasing to exist. There is no translatable word for a concept like space particles, maybe strings? They speak of another untranslatable concept we call Mind existing since beginning-less time. It takes heroic joyful effort over countless kalpas to fully realize such concepts that are beyond the brain's capacity for understanding. Me, I'm still trying to imagine Graham's number raised to the power of Graham's number a Graham's number of times.
Obquote: "If you actually tried to picture the concept of Graham's number in your head, your head would collapse into a black hole."
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