Planetary Nebulae / Supernovae
This page is divided into two categories: planetary nebulae and supernovae.
Planetary nebulae are shells of ionized gas surrounding star. More precisely, this gas has been ejected by the star during it’s final stages of “life”. These halos also usually include a white dwarf (or dead star) at their center, emitting radiation that causes the ejected matter to glow. These nebulae are comprised of all the elements that make up a star, making them extremely colorful. Our own sun will face a similar demise.
The first planetary nebula ever seen by human eyes was cataloged by Charles Messier in his list of “not comets”, called M 27. Sir William Herschel first called them “planetary” because their often circular appearance looked similar to a faint planet.
Supernovae are also the remnants of a dead star, but these stars met a slightly more violent end. Once stars are born with a certain amount of mass, they burn through their fuel very quickly (by cosmic scale) and eventually run out. Without the fusion at the stars core, gravity takes over, pulling the star back in upon itself. Eventually the star can no longer contract and explodes back outward again due to nuclear forces in the stars atoms, thus causing a supernova. These events are destructive and extremely brief, most only being visible for a couple of days. They are so bright that they can be seen in other galaxies, and, when near enough to earth, can be seen during the day.