The nearby Triangulum galaxy, one of the closest spirals to us in the Universe. The pink color tracing the spiral arms is strong evidence of new star formation. (European Southern Observatory (ESO))

New Stars Turn Galaxies Pink, Even Though There Are No ‘Pink Stars’

A color you’ll never find in a star is responsible for the universal color of star-forming regions.

If you look through a telescope’s eyepiece, distant galaxies always appears white.

Spiral-shaped galaxies, so long as no new matter routinely falls into them, were long thought to remain static in size and extent over time. Through an eyepiece, a human being will see only the dominant, white color of the starlight averaged together. (NASA, ESA and W. Harris — McMaster University, Ontario, Canada)

But with advanced cameras that pick up individual photons, some regions show a different color: pink.

This visible-light image composite of the Orion Nebula was created by the Hubble Space Telescope team back in 2004–2006. The colorations presented here are scientifically accurate. (NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team)

In our own galaxy, it’s the overwhelming color of star-forming regions like the Orion Nebula.

A young, star-forming region found within our own Milky Way. Note how the material around the stars gets ionized, and over time becomes transparent to all forms of light. Until that happens, however, the surrounding gas absorbs the radiation, emitting light of its own of a variety of wavelengths. (NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration; Acknowledgment: R. O’Connell (University of Virginia) and the WFC3 Scientific Oversight Committee)

In some galaxies, the pink color can dominate a telescope’s entire field-of-view.

The starburst galaxy Henize 2–10, located 30 million light years away. When an entire galaxy forms stars, it undergoes a starburst, turning pink where the most active new star-formation occurs. (X-ray (NASA/CXC/Virginia/A.Reines et al); Radio (NRAO/AUI/NSF); Optical (NASA/STScI))