This photograph of the coil-shaped Helix Nebula is one of the largest and most
detailed celestial images ever made.
The composite picture is a seamless blend of ultra-sharp images from NASA's
Hubble Space Telescope combined with the wide view of the Mosaic Camera on
the National Science Foundation's 0.9-meter telescope at Kitt Peak National
Observatory near Tucson, Ariz.
The image shows a fine web of filamentary "bicycle-spoke" features embedded in
the colorful red and blue ring of gas. At 650 light-years away, the Helix is one of the
nearest planetary nebulae to Earth. A planetary nebula is the glowing gas around a
dying, Sun-like star.
The Helix appears to be round because we are looking at one end of the nebula. It
is actually a trillion-mile-long tunnel of glowing gases.
The bicycle spoke features are a forest of thousands of comet-like tentacles that are
embedded along the inner rim of the nebula. The tentacles point toward the central
star, which is a small but super-hot white dwarf [white dot in center of nebula] that
seems to float in a sea of blue gas.
These tentacles formed when a hot "stellar wind" of gas plowed into colder shells of
dust and gas ejected previously by the doomed star. These comet-like tentacles
have been observed from ground-based telescopes for decades, but never have
they been seen in such detail. They may actually lie in a disk encircling the hot star,
like an animal's collar.