A Whirlpool Warhol:The Changing Face of Galaxies from the Visible to the Infrared

It all depends on how you look at it—galaxies appear different in visible light (i.e., wavelengths that our eyes are sensitive to) than at longer wavelengths, in the infrared. In visible light (panel a), the Whirlpool galaxy M51 and its companion show fine filigree dust lanes that obscure and redden the light from background stars. In the infrared (panels c and d), the dust lanes, warmed by starlight, glow brightly. Panel b combines the visible light image, taken at the Kitt Peak 2.1m telescope, and the infrared images from NASA’s Spitzer Space Telescope.