UA camera snaps shots of Uranus

The images, taken in July and released yesterday by NASA's Space Telescope Science Institute, were developed by University of Arizona Lunar and Planetary Laboratory scientist Erich Karkoschka. They show Uranus's moons, rings and six distinct clouds in the planet's upper atmosphere.

The pictures were snapped by the UA's Near-Infrared Camera and Multi-Object Spectrometer (NICMOS), which was installed aboard Hubble by space shuttle astronauts in February.

The images show detail not visible using traditional telescopes, Karkoschka said.

"In visible light, Uranus looks very bland, but in Near Infrared we can see a lot more colors and contrasts. It showed very high contrast features," he said.

Karkoschka is using the Hubble data to test current theories about Uranian atmospheric circulation, he said.

The six high altitude clouds, each roughly the size of Europe may be made of methane or ammonia ice crystals in Uranus' mostly hydrogen and helium atmosphere, Karkoschka said.

The images also show what is almost certainly methane ice haze around the planet's south pole, Karkoschka said.

He said the polar haze may be the thickness of Los Angeles smog, while the clouds may be similar to the high-altitude cirrus clouds seen yesterday in Tucson's southern sky.

These clouds, however, are incomparably higher above the planet's surface than clouds on Earth.

Uranus is four times the diameter of Earth. Its atmosphere may make up as much as three quarters the diameter of the planet, Karkoschka said.

Uranus is the third largest planet in the solar system and the seventh planet from the sun. It orbits the sun once in 84 Earth years.

The Hubble images also show eight of the 10 known Uranian satellites and its three rings. Scientists do not know what the rings or the dark, charcoal-colored moons are made of, but Karkoschka said he hopes the NICMOS data will allow him to narrow the possibilities.

Designed and built over 13 years by UA astronomer Rodger Thompson and a team at the UA's Steward Observatory, NICMOS detects heat radiation. It has allowed scientists to see farther into the universe than ever before, Thompson said.

Last month UCLA astronomers announced they had used NICMOS to observe what they believe to be the most powerful star yet discovered.

"The impact is really fantastic. We are now able to look at the universe with very sharp eyes in a wavelength we have never seen before," Thompson said.