A spiral galaxy seen from overhead, with its two major arms spiraling out from its bright white core. At the end of the arm on the right is another bright white blob, this is a second galaxy. The arms are bluish and purple, peppered with countless stars.

Hubble Messier 51, The Whirlpool Galaxy

The graceful, winding arms of the majestic spiral galaxy M51 appear like a grand spiral staircase sweeping through space. They are actually long lanes of stars and gas laced with dust. Such striking arms are a hallmark of so-called grand-design spiral galaxies. In M51, also known as the Whirlpool galaxy, these arms serve an important purpose: they are star-formation factories, compressing hydrogen gas and creating clusters of new stars.

Credits: NASA, ESA, S. Beckwith (STScI) and the Hubble Heritage Team (STScI/AURA)