M57: The Ring Nebula
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
Hubble 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.