M27: Not A Comet
Credit: FORS Team, 8.2-meter VLT, ESO
Explanation: While searching the skies above 18th century France
for comets, astronomer Charles Messier diligently recorded this
object as number 27 on his list of things which are definitely not
comets. So what is it? Well, 20th century astronomers would classify
it as a Planetary Nebula ... but it's not a planet either, even
though it may appear round and planet-like in a small telescope.
Messier 27 (M27) is now known to be an excellent example of a gaseous
emission nebula created as a sun-like star runs out of nuclear fuel
in its core. The nebula forms as the star's outer layers are expelled
into space, with a visible glow generated by atoms excited by the dying
star's intense but invisible ultraviolet light. Known by the popular
name of the "Dumbbell Nebula", the beautifully symmetric interstellar
gas cloud is about 1,200 light-years away in the constellation Vulpecula.
This gorgeous synthetic color picture of M27 was produced during testing
of the European Southern Observatory's new Very Large Telescope.
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