Scary Eyes
The Helix Nebula (NGC7293) is a great example of what is called a “planetary nebula” (PN), and is one of the closest PNs to Earth at about 700 light-years. “Planetary Nebula” is a misnomer that derives from their typically round appearance, which might be mistaken for a planet when viewed through primitive telescopes. They are actually emission nebulae resulting from a star shedding its outer layers as it approaches its end of life. Most PNs have a similar appearance, but this image is the best example from my small selection, partly because of its large angular size, and partly because it […]