Question about HUDF

[leo_1965]

Hello,<br /><br />Regarding the Hubble Ultra Deep Field image - I realize this is just a tiny portion of the viewable cosmos from our perspective (about one-tenth the size of the full moon, from what I understand). Is this representative of the entire viewable sky? I mean, if Hubble was pointed at any other portion of the sky, would we see such numbers of galaxies, or was that area so rich with objects that they decided to concentrate on it? Thanks.

 

[robnissen]

Actually, it is the exact opposite. They picked a part of the sky that had no stars in it and away from the Milky Way, so that stars and dust of the Milky Ways wouldn't block the light of distant galaxies. In general, Hubble would get a similar number of galaxies in any direction, but it would not always be able to see as many because of intervening dust.

 

[le3119]

Basically, the Cosmological Principle states that every locality in the universe is similiar in composition, distribution of galaxies, no matter you go.

 

[Saiph]

Rob and Leo have it right.<br /><br />The cosmological principle isn't the strongest one in the world. It's a consequence of how we believe the universe was created (Big Bang). So far observation has matched it very nicely though. There are no large scale (and non-local) discrepancies in the universal distribution.<br /><br />We see structure all over the place, but it's spread uniformly, much like the waves in a pool create distinct patterns of light, but are spread without bias across the pool (or rather, can be). <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>