New
91. view of the
Helix Nebula
This composite image is a view of the colorful Helix Nebula taken with the Advanced
Camera for Surveys aboard the Hubble Space Telescope and the Mosaic II Camera on
the 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile. The object is
so large that both telescopes were needed to capture a complete view. The Helix is a
planetary nebula, the glowing gaseous envelope expelled by a dying, sun-like star. The
Helix resembles a simple doughnut as seen from Earth. But looks can be deceiving. New
evidence suggests that the Helix consists of two gaseous disks nearly perpendicular to
each other.
Credit: NASA, ESA, C.R. O’Dell (Vanderbilt University), and M. Meixner, P. McCullough,
and G. Bacon ( Space Telescope Science Institute)
Hubble’s top discoveries “is a very personal list:
“1) The accelerating universe, kind of a no-brainer there, we think most
people would agree with that. The Nobel committee thought so, too.
“2) Accurate determination of the Hubble constant, the current rate at
which the universe is expanding. Prior to Hubble the telescope, Hubble
the number wasn’t known to better than a factor of two. It’s now at
~10% accuracy.
“3) Discovery that every large galaxy has a supermassive black hole
at its center. This one might not make everyone’s list, but it’s what we
work on!”
— Dr. Bradley M. Peterson & Dr. Gisella De Rosa
Pro fessor and Chair of Astronomy
Ohio State University
Columbus, Ohio
Visiting Astronomer
Space Telescope Science Institute
Baltimore, Maryland