M 57 Ring Nebula -- Planetary Nebula in Lyra
Stars are born, grow old and eventually die. What happens in their old age is dependent upon
their mass. For a star that is around the mass of our sun, when it runs out of fuel at its core, it
will expel a huge amount of gas into space. The thrown off gas is called a Planetary Nebula.
Our sun will not enter this stage for a few billion years, so we can relax for a while -- life on
Earth will not survive our sun shedding its outer surface. The Ring Nebula is the remains of
sun sized star that formed its Planetary Nebula about 20,000 years ago. It is expanding at a
rate of about 16.5 miles per second. The core of the remaining white-dwarf star is at the
center of the ring, but is too dim to be seen with my telescope (and thus not in the drawing).