Explore the planetary nebula ESO 456-67. What shapes do you see? Leave a note in the comments below.
Although called a planetary nebula, these starry objects have nothing to do with planets. In early telescopes of the 18th century, while astronomers were searching for new planets, these small and round nebulae looked like planets. The nebulae are much farther away and much larger than any planet in our solar system. Planetary nebulae are the last stage in the life of a star similar to our Sun in size. As these stars approach the end of their long lives, they run out of hydrogen fuel. They bloat and throw off shells of gas and dust. Sometimes, the bubbles they produce are smooth and round. But other times, they are complex with material shooting away in different directions.
As you explore ESO 456-67, look for the remaining star in the center of the blue area. Astronomers call these stars white dwarfs. They are hot and small. Over billions of years, this star will cool to become a warm cinder. The blue area surrounding the white dwarf is a hot bubble of gas. White dwarfs give off intense ultraviolet radiation that causes the gas of the planetary nebula to glow. Other regions of the nebula contain different elements that glow different colors.
ESO 456-67 is found about 10,000 light-years from Earth toward the rich starfields in the constellation Sagittarius, the Archer. Light from the planetary nebula began traveling toward our eyes on Earth just about the time when humans developed agriculture techniques in Mesopotamia.