The Ring Nebula is a cosmic preview of how our Sun will die in 5 billion years.

The Ring Nebula, also known as M57, was discovered by French astronomer Antoine Darquier de Pellepoix in 1779. It is the classic example of a planetary nebula, a term coined by William Herschel because these objects resembled planets through early telescopes. Despite the name, they have nothing to do with planets and are actually the final stages of stellar evolution for stars with masses between 0.8 and 8 times that of our Sun.Our Sun is currently a main-sequence star about 4.6 billion years old. In approximately 5 billion years, it will exhaust the hydrogen fuel in its core and expand into a red giant. During this phase, it will likely engulf Mercury, Venus, and possibly Earth. Eventually, the Sun will eject its outer layers in a series of pulses, creating a glowing shell of ionized gas similar to what we see in M57 today.The intense ultraviolet radiation from the exposed hot core ionizes the surrounding gas, causing it to glow in different colors based on the elements present. The blue light at the center of the Ring Nebula comes from ionized helium, while the outer red edges are primarily nitrogen and sulfur. The remaining core will become a white dwarf, a stellar remnant about the size of Earth but with a mass comparable to the Sun.Recent observations from the James Webb Space Telescope in 2023 have provided unprecedented detail of the Ring Nebula's structure. These images revealed roughly 20,000 dense clumps of molecular hydrogen gas within the nebula. This level of detail helps astrophysicists refine their models of how stars like our Sun distribute heavy elements back into the galaxy at the end of their lives.