Talk:Void (astronomy)

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voids are approx size of superclusters, supervoids are approx size of walls... or so it seems? (talk) 08:06, 2 August 2008 (UTC)

old list[edit]

A 1994 census lists a total of 27 supervoids with a distance of up to 740 Mpc.[1]

# Name Distance (h-1Mpc)[2] Diameter (h-1Mpc)[3]
1 134 88
2 207 96
3 216 72
4 241 86
5 129 92
6 236 72
7 248 100
8 201 76
9 Southern Local Supervoid 96 112
10 246 144
11 160 92
12 227 106
13 246 94
14 167 68
15 241 98
16 222 74
17 216 94
18 119 102
19 119 108
20 Boötes void
(Great Void)
216 78
21 143 116
22 246 96
23 219 72
24 Northern Local Supervoid 61 104
25 198 74
26 246 80
27 241 70

Not shown in the above chart:

This was the original list on the page. (talk) 12:28, 15 November 2008 (UTC)

Unit of distance[edit]

Mpc is a unit of distance so what does the h stand for in h-1Mpc and why should that still be a unit of distance? I am tempted to remove any occurrence of h-1 unless a definition is provided. —Preceding unsigned comment added by (talk) 11:25, 24 August 2009 (UTC)

From [[1]],
Galactic distances are sometimes given in units of Mpc/h (as in "50/h Mpc"). h is a parameter in the range [0.5,0.75] reflecting the uncertainty in the value of the Hubble constant for the rate of expansion of the universe (h = H / (100 km/s/Mpc)). The Hubble constant becomes relevant when converting an observed redshift z into a distance using the formula d ≈ (c / H) × z (where c is the speed of light).
I'll change the "h-1"s to "/h"s and link to the def.
Saintrain (talk) 12:48, 24 August 2009 (UTC)


Wonder if the voids have a black hole at their center. If that were true someone else would have thought of it and tried to check for any form of evidence. —Preceding unsigned comment added by (talk) 00:19, 10 September 2009 (UTC)

I don't think so, matter appears to leave voids for concentrations of matter. If there were black holes, they would attract matter... ofcourse this is assuming extremely supermassive blackholes are what you're referring to. There are black holes in the voids because there are galaxies in the voids. Galaxies have stars, which produce stellar mass black holes. The galaxies themselves have supermassive central black holes. (talk) 01:29, 21 September 2009 (UTC)
Could it be possible that one or more blackholes sucked in pretty much everything they could, and what is left is the stuff at the borders of the void that due to the expansion of space are moving away faster than the blackholes can pull at that distance? --TiagoTiago (talk) 21:17, 7 November 2011 (UTC)
If there was a supercluster mass blackhole in a void it would bend light and it would have a large gravitational lensing effect, which is not observed. Known dark matter is plotted in this diagram File:COSMOS 3D dark matter map.jpg but I cannot see how it aligns with voids or clusters. Graeme Bartlett (talk) 02:35, 8 November 2011 (UTC)
You should propose realistic scenarios. The only known way to make black holes is to stuff a lot of conventional matter together as in a galaxy. Such collapse is inefficient and will throw out a lot of stars and gas. That'd be easily visible. I think you have a fundamental misunderstanding of what gravity is. Gravity is a force field, not suction, and a black hole is not a giant vacuum cleaner. That means that a star falling in a gravity field will convert its gravitational potential energy into kinetic energy, speeding up. So, if it doesn't exactly hit the black hole (which is unlikely as it would take incredible aim), it will just speed past the black hole like a comet, then head back up the gravity well, losing kinetic energy as it slows down. So, no energy is actually lost anywhere, just converted from potential to kinetic energy and back. The only known way to lose the kinetic energy is to hit something on the way. That will release heat, in practice in the form of an accretion disc of a quasar. They are the brightest objects in the universe. --vuo (talk) 21:36, 29 August 2014 (UTC)

Additional info[edit]

From SIMBAD: [2] - a list of voids in the SIMBAD database, so we can construct a proper list article. (talk) 01:29, 21 September 2009 (UTC)

This would be a good way to expand this article: arXiv:0912.3473 (talk) 07:01, 18 June 2010 (UTC)

Baryon acoustic oscillations[edit]

Vuo added this: "Voids were formed by baryon acoustic oscillations" with no citation. Surely this is only a hypothesis and not an accepted fact. How should this statement be qualified? Graeme Bartlett (talk) 08:21, 25 May 2011 (UTC)


This article only talks about what a void physically is and not about the history of a void. The history section could talk about how the idea of a void was first introduced by the atomists, turned down by Aristotle and then later accepted by Christaan Huygens and Evangelista Torricelli. I think adding this section would give the article more substance and make it more informational. What do you think? Chargerfan12 (talk) 00:50, 24 May 2013 (UTC)

Local Supervoid Update[edit]

According to recent reports the local supervoid is much larger than previously thought and may be the largest known object in the universe.[5] 551 Mpc if my math is correct. Maybe this information should be added to this page or the list of voids? Grizzlebizzle (talk) 09:32, 21 April 2015 (UTC)

  1. ^ Einasto, M (1994-07-15), "The Structure of the Universe Traced by Rich Clusters of Galaxies", Monthly Notices of the Royal Astronomical Society, 269 
  2. ^ To the center of the void
  3. ^ This is the diameter of the largest sphere one can describe inside the void that contains no superclusters. Some voids have an elongated shape, so this diameter may underrepresent the size of some voids.
  4. ^ "Astronomers Find Enormous Hole in the Universe". National Radio Astronomy Observatory Press release, retrieved 24 August 2007.
  5. ^ "Cold Spot suggests largest structure in Universe: A supervoid 1.3 billion light years across" Royal Astronomical Society (RAS) April 20, 2015