It turns out that one of the most prominent space artists predicted how a strange celestial object would look — 50 years in ...

At this stage, the star becomes a large red giant ... Within this nebula, the hot core of the star remains—crushed to high density by gravity—as a white dwarf with temperatures over 180,000 ...

Many a blue nebula has been discovered, shining by light from a hot blue star. If the reflection theory is correct, red nebulae should also exist, with comparatively cool red stars as illuminators.

creating massive shockwaves that extend over 62 billion miles (100 billion kilometres) into space. These shockwaves form the nebula's distinctive spider-leg-like arcs.