one way that can help estabilish age, without using the redshift relationships, is metallicity. The older it is, the more time stars have been building up the metal content.<br /><br />As for where are quasars now?<br /><br />There are many within only a few billion light years, thats pretty recent, and current. They aren't as bright as the more distant ones (note, I'll give a nod to the uncertainty in <i>some</i> quasars distances), but that's also to be expected. As the host galaxies age, and closer ones are older (just because of light travel time)...the material thins out, feeding the BH of the quasar less.<br /><br />I.e., after 15 billion years, they've eaten their food supply. <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>