Herschel's infrared view of the Whirlpool Galaxy (M51)
The Whirlpool Galaxy, also known as M51 (or NGC 5194), is one of the most spectacular examples of a spiral galaxy. With two spiral arms curling into one another in a billowing swirl, this galaxy hosts over a hundred billion stars and is currently merging with its companion, the smaller galaxy NGC 5195.
Around 30 million light-years away, the Whirlpool Galaxy is close enough to be easily spotted even with binoculars. Using the best telescopes available both on the ground and in space, astronomers can scrutinise its population of stars in extraordinary detail.
This image shows the Whirlpool Galaxy as seen at far-infrared wavelengths by ESA's Herschel Space Observatory.
The infrared light collected by Herschel reveals the glow of cosmic dust, which is a minor but crucial ingredient in the interstellar material in the galaxy's spiral arms. This mixture of gas and dust provides the raw material from which the Whirlpool Galaxy's future generations of stars will take shape.