It is a gorgeous nebula. I think the explanation you're looking for has to do with the perspective of the nebula relative to Earth. There are lots of examples of bipolar nebula (perhaps the most famous of these is Eta Carina), this one happens to have its poles (at 10 o'clock and 4 o'clock on the image) at nearly right angles to our line of sight. It's sort of like the Sun's view of Earth at the equinox. The "rungs" are described as possibly resulting from ripples or waves on the outermost regions of the dying star itself, projected outward as the star sheds its outer layers of gas. A dying star having ripples or waves on its outer regions as a result of the pulsating death throes at its core is not hard to imagine. It is an amazing image. Seth Jarvis -----Original Message----- From: utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com [mailto:utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com] On Behalf Of Joe Bauman Sent: Friday, April 13, 2007 12:40 AM To: Utah Astronomy Subject: [Utah-astronomy] Astonishing nebula Here's the most stunning nebula I've ever seen! Anyone want to offer an explanation? Best wishes, Joe http://www.space.com/scienceastronomy/070412_symmetrical_nebula.html --------------------------------- Expecting? Get great news right away with email Auto-Check. Try the Yahoo! Mail Beta. _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com

The answer is "yes!" Google-up images of other bipolar planetary nebulae, such as the Butterfly Nebula or the Ant Nebula, do a little mental reorienting and image cropping, and you'll see the same symmetries. Seth -----Original Message----- From: utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com [mailto:utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com] On Behalf Of Joe Bauman Sent: Friday, April 13, 2007 9:10 AM To: Utah Astronomy Subject: RE: [Utah-astronomy] Astonishing nebula Thanks, Seth. I much appreciate your explanation. I wonder if other nebulas we see would look more like this if they were oriented differently. Best wishes, Joe _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com