the bones of Andromeda

[Martin]

http://www.spitzer.caltech.edu/Media/releases/ssc2005-20/ssc2005-20a.shtml

 

a spiral galaxy has a skeleton of dustcloud

the basic structure of the arms is made of dustcloud

 

the Spitzer infrared telescope satellite took a picture of Andromeda galaxy in 24 micron infrared (visible is 0.4 to 0.7 micron, so this wavelength is way longer than visible light)

 

it is kind of like taking an Xray photograph and seeing the bones. you dont see the stars (unless it is a star that happens to be surrounded by a dustcloud)

 

thanks to Sean Carroll, of cosmic variance blog, for flagging this

[ecoli]

good stuff, thanks for sharing.