Three-color far-infrared image of M51, the Whirlpool Galaxy.

Red, green and blue correspond to the 160-micron, 100-micron and 70-micron wavelength bands of the Herschels Photoconductor Array Camera and Spectrometer, PACS instruments.

Glowing light from clouds of dust and gas around and between the stars is visible clearly. These clouds are a reservoir of raw material for ongoing star formation in this galaxy. Blue indicates regions of warm dust that is heated by young stars, while the colder dust shows up in red.