Revealing the two-armed spiral
Jun 8, 2015
According to recent popular science articles, there has been something of a revival of the traditional idea that our Milky Way is a 4-armed spiral galaxy, as opposed to having two spiral arms, as seen in the currently most popular rendition of our home Galaxy, shown here:
This artistic rendering was motivated by findings based on the observations of theNASA Spitzer Space Telescope. Indeed, this image was made expressly for the purpose of communicating some of the main findings from Spitzer with regards to Galactic structure, and in particular the message that our Galaxy is dominated by a 2-arm rather than a 4-arm structure.
Just how different the image above was from previous renditions of the Milky Way can be seen in the comparison below:
Interestingly these two images were made by the same artist, Robert Hurt, the one on the left from 2008 (post-Spitzer), and the one on the right from 2005 (pre-Spitzer). In many ways the new picture of the Milky Way on the left is a significant improvement ...