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Author Topic: Giant hole found in space  (Read 1025 times)

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Offline VekseidTopic starter

Giant hole found in space
« on: August 28, 2007, 11:45:01 AM »
Arxiv paper

APoD Link

Quote
We detect a dip of 20-45% in the surface brightness and number counts of NVSS sources smoothed to a few degrees at the location of the WMAP cold spot. The dip has structure on scales of approximately 1-10 degrees. Together with independent all-sky wavelet analyses, our results suggest that the dip in extragalactic brightness and number counts and the WMAP cold spot are physically related, i.e., that the coincidence is neither a statistical anomaly nor a WMAP foreground correction problem. If the cold spot does originate from structures at modest redshifts, as we suggest, then there is no remaining need for non-Gaussian processes at the last scattering surface of the CMB to explain the cold spot. The late integrated Sachs-Wolfe effect, already seen statistically for NVSS source counts, can now be seen to operate on a single region. To create the magnitude and angular size of the WMAP cold spot requires a ~140 Mpc radius completely empty void at z<=1 along this line of sight. This is far outside the current expectations of the concordance cosmology, and adds to the anomalies seen in the CMB.

Offline Sabby

Re: Giant hole found in space
« Reply #1 on: August 28, 2007, 08:52:43 PM »
Why do I feel dumb...

Offline VekseidTopic starter

Re: Giant hole found in space
« Reply #2 on: August 29, 2007, 12:14:55 AM »
In astronomy, a Void is simply an 'unusually' empty region of space.  A simple wat yo think about it is to imaging that galxies are laid about as filaments, like a giant loaf of bread or a great web.  Voids are those large empty spaces in between.

Our Milky Way lies on one such filament plane, called (rather predictably) the SuperGalactic Plane, bounded by three 'nearby' superclusters of galaxies.  It is bounded by a couple of local supervoids.

This newly discovered void is truly immense - something like ten times the size of any other known.  With the rest of the Universe seeming so homogenous, it is a cosmic curiosity - what caused it, etc..


Offline Sabby

Re: Giant hole found in space
« Reply #3 on: August 29, 2007, 12:19:51 AM »
Ah. Well, while I do feel quite small for needing it broken down in such a way, yes, that is very interesting :) I just can't seem to fathom how there can be an area where there is no existing matter.

Offline OldSchoolGamer

Re: Giant hole found in space
« Reply #4 on: August 29, 2007, 02:47:59 AM »
Reminds me of that Black Sabbath song, Into the Void.

Offline VekseidTopic starter

Re: Giant hole found in space
« Reply #5 on: August 30, 2007, 10:21:03 AM »
Ah. Well, while I do feel quite small for needing it broken down in such a way, yes, that is very interesting :) I just can't seem to fathom how there can be an area where there is no existing matter.

Galaxies within a void are called field galaxies.  They're doomed to a rather lonely existence as the Universe expands, but voids are not completely empty - just empty relative to their surroundings.

Offline Llianna

Re: Giant hole found in space
« Reply #6 on: August 30, 2007, 11:11:08 AM »
Wow...I feel really dumb...lol! But really small too O_o