Let's look at a
planetary nebula nearly perfect spherical shape, whose name Abell 39 (Abell
39).
Today in our galaxy
"Milky Way" is known more than 1500 planetary nebulae that are
astronomical substance consisting of ionized gas shell and the central star - a
white dwarf. Planetary nebulae are fast in astronomical terms the phenomenon,
which lasts only a few tens of thousands of years. For comparison, the life of
the parent star is a few billion years.
