Tricolor composite image of W3 Main where massive stars are being born. Red colored objects to the left of center are extremely young massive stars, surrounded by less massive stars of one million years old. Nebulas with a variety of colors and appearances are ionized gas reflecting light from these stars. Filamentary dark clouds are also conspicuous. The line at bottom left shows a scale of 0.2 parsecs, which is approximately 40 thousand astronomical units.
National Astronomical Observatory of Japan