EYE OF GOD

The eye of God is an authentic NASA image taken by both, the ESO Very Large Telescope and with the NASA/ESA Hubble Space Telescope. Known as the Helix Nebula, it is one of the largest and oldest planetary nebulae known.

In astronomy, distances are measured by light years. One light year is the distance that light travels in a year. The Helix is 700 light years away and it is about 4 light years across. This makes it many times larger than our entire solar system.

Despite being photographically very spectacular the Helix is hard to see visually as its light is thinly spread over a large area of sky (it covers an area of the sky about a quarter of the full Moon).

The history of its discovery has been very obscure. It first appears in a list of new objects compiled by the German astronomer Karl Ludwig Harding in 1824. The name Helix comes from the rough corkscrew shape seen in earlier photographs.

The eye of God is the nearest example of what happens to a star like our own Sun as it approaches the end of its life and runs out of fuel. The outer gasses of the star expell into space and appear from our vantage point as if we are looking down a helix (cylinder).

The central core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. It's technical designation or location is NGC 7293, which is the constellation Aquarius. Aquarius is one of the oldest constellations in the sky.

The above picture is a composite of only one of the released images from the ACS instrument on the Hubble Space Telescope and wide-angle images from the Mosaic Camera on the WIYN 0.9-m radio Telescope at Kitt Peak National Observatory, located on a mountain in the U.S. state of Arizona.

Because the Helix is relatively close it can be studied in much greater detail than most other planetary nebulae and has been found to have an unexpected and complex structure. All around the inside of the ring are small blobs, known as “cometary knots”, with faint tails extending away from the central star. They look remarkably like droplets of liquid running down a sheet of glass.

Although they look tiny, each knot is about as large as our Solar System. These knots have been extensively studied, both with the ESO Very Large Telescope (located on a mountain in the Atacama Desert in northern Chile), and with the NASA/ESA Hubble Space Telescope, but remain only partially understood.

In November of 2002, valuable Hubble observing time became available during the Leonid meteor storm. To protect the spacecraft, including HST's precise mirror, controllers turned the aft end into the direction of the meteor stream for about half a day.

Fortunately, the Helix Nebula was almost exactly in the opposite direction of the meteor stream, so Hubble used nine orbits to photograph the nebula while it waited out the storm. To capture the Helix Nebula, Hubble had to take nine separate snapshots.

The eye of God is a popular target of amateur astronomers and can be seen with binoculars as a ghostly, greenish cloud in the constellation Aquarius. Larger amateur telescopes can resolve the ring-shaped nebula, but only the largest ground-based telescopes can resolve the radial streaks.

After careful analysis, astronomers concluded the nebula really isn't a bubble, as earlier thought, but is a cylinder that happens to be pointed toward Earth.