Much of the sky indeed glows blood red. That glow, too dim for our eyes to discern, is hydrogen gas excited by the stars. Nope, space is not a void.
These clouds in the northern cross were captured with my 530mm focal length telescope in my Portland OR backyard. Extremely narrow bandwidth filters separate the city light from from light coming from space. My camera is a QHY600 camera (IMX455) cooled to -10c.
16 hours of exposures were stacked. I also blended in a little luminance data to the blue sections for sharpness. That data came from a larger telescope I have in the Sierra Mountains.