Messier 57 (M57) – The Ring Nebula

Messier 57 (M57), commonly known as the Ring Nebula, is a planetary nebula about 2,000 light years from our solar system in the Lyra constellation.

The name “planetary nebula” is a misnomer. Planetary nebulas have nothing to do with planets. Astronomers in the 18th century thought these objects were planets, but now we know differently. When a star with 80% to 800% of the sun’s mass begins to run out of hydrogen fuel, it starts fusing helium into heavier elements such as carbon and oxygen. As it does this, the additional energy from those stepped-up levels of fusion cause it to expel its outer layers.

Ultimately, the star expels all its outer layers from its core, leaving the core exposed in sort of a cosmic burp. Once all the helium is burned up, fusion ceases in the core and what is left is a giant, dense ball of carbon (about the size of the earth, but with the mass of the sun)—a diamond in the sky called a “white dwarf.” That core no longer produces new energy, but it’s still extremely hot and gives off copious amounts of radiation, ionizing the gas it expelled earlier. That cloud of gas then eventually dissipates. But before it does, the ionized gas gives off light we can record here on earth with our cameras (if the star is close enough to us).

I’ve captured this both in true color and also in a version that focuses on emissions from hydrogen and oxygen gas. You can see the difference using the slideshow above. But the chemical composition of the Ring is more complex even than that. This NASA video explains more about it:

The image also reveals the faint, faraway spiral galaxy IC 1296 at a position of about two o’clock in relation to the Ring. It’s an astonishing 238 million light years from Earth and is roughly the same size as our Milky Way galaxy.