The Ring
Except for the Rings of Saturn,
The Ring Nebula (M57) is probably the most famous celestial band.
This
planetary nebula's simple, graceful
appearance is thought to be due to perspective --
our view from planet Earth
looking straight into what is actually a barrel-shaped cloud of
gas shrugged off by a dying central star.
Astronomers of the Hubble Heritage Project produced
this strikingly sharp image from Space Telescope observations
using natural appearing colors to indicate the temperature of the stellar
gas shroud.
Hot blue gas near the energizing central star
gives way to progressively cooler green and yellow
gas at greater distances with
the coolest red gas along the outer boundary.
Dark, elongated structures
can also be seen near the nebula's edge.
The Ring Nebula is about one light-year across and 2,000 light-years
away in the northern
constellation Lyra.