This picture of infrared light from the Egg Nebula shows the
last gasps of a dying star. Because infrared light is invisible
to humans, we have used three different colors to represent the
three wavelengths of infrared light.
Blue represents intermediate-wavelength infrared starlight reflected
by dust particles around the dying star. Green represents longer-wavelength
reflected starlight. Red represents infrared light from hydrogen
molecules surrounding the star.
The red color indicates where a belt of molecular gas surrounds
the star. The blue color is strongest above and below the belt,
because that's where the most starlight is escaping.