Cassini Snaps First Color Postcard On Jupiter Flyby

This color image of Jupiter was taken by the Cassini narrow angle camera from a distance of 81.3 million kilometers (about 50 million miles) from the planet. It is composed of images taken in the blue, green and red regions of the spectrum and is therefore close to the true color of Jupiter that one would see through an Earth-based telescope.

The image is strikingly similar to images taken by the Voyager 1 and 2 spacecraft more than 21 years ago, illustrating the remarkable stability of Jupiter's weather patterns. The parallel dark and bright bands and many other large-scale features are quasi-permanent structures that survive despite the intense small-scale activity ongoing in the atmosphere.

The longevity of the large-scale features is an intrinsic property of the atmospheric flows on a gaseous planet, like Jupiter, having no solid surface; but smaller features, like those in the dark bands to the north and south of the equator, are observed to form and disappear in a few days. Similar behavior was observed during the Voyager era.

Everything visible on the planet is a cloud. Unlike Earth, where only water condenses to form clouds, Jupiter has several cloud-forming substances in its atmosphere. The updrafts and downdrafts bring different mixtures of these substances up from below, leading to clouds of different colors. The bluish features just north of the equator are regions of reduced cloud cover, similar to the place where the Galileo atmospheric probe entered in 1995. They are called "hot spots" because the reduced cloud cover allows heat to escape from warmer, deeper levels in the atmosphere.

The Galilean satellite Europa is seen at the right, casting a shadow on the planet. It is this satellite which scientists believe holds promise of a liquid ocean beneath its surface. Photo by NASA, JPL, University of Arizona. DESKTOP AVAILABLE

Washington (AFP) October 9, 2000
The US Cassini space probe has provided the first color photos of Jupiter, which reveal a surprising stability in the gaseous planet's atmospheric conditions and weather patterns, researchers said Monday.

The images captured by the probe are "strikingly similar" to those provided more than 21 years ago by the space probes Voyager 1 and Voyager 2, said Carolyn Porco, director of the Cassini Imaging Science team at the University of Arizona in Tucson.

She described the "startlingly sharp" images as being "close to the true color of Jupiter that one would see through an Earth-based telescope."

Researchers say the persistence of the planet's weather patterns is an intrinsic characteristic of the atmospheric flows of planets that, like Jupiter, have no solid surface.

"The parallel dark and bright bands and many other large-scale features are quasi-permanent structures that survive despite the intense small-scale activity ongoing in the atmosphere," Porco said, describing the appearance of these conditions in the photo.

Unlike on Earth, where only water vapor forms clouds, Jupiter is covered by clouds of various hues that are created by many different gases. The clouds' colors are created as gases are carried by rising and falling atmospheric flows, according to researchers.

The composite-color photo was made from images captured by Cassini's narrow-angle camera "in the blue, green and red regions of the spectrum" on October 4, when the probe was 81.3 million kilometers (50.5 million miles) from Jupiter, Porco said.

The probe is now heading toward Saturn and is expected to reach the ringed planet in July 2004.

The US National Aeronautics and Space Administration, the European Space Agency and the Italian Space Agency have worked together on the Cassini project.

The first color image of Jupiter taken by cameras on the Cassini spacecraft shows that weather on the giant planet is the same kind of weather that Voyager 1 and 2 spacecraft photographed more than 21 years ago.

The color photo is made from images taken by the Cassini narrow angle camera in the blue, green and red regions of the spectrum on Wednesday, Oct. 4, when the spacecraft was 81.3 million kilometers (about 50 million miles) from the planet. The composite-color photo is therefore close to the true color of Jupiter that one would see through an Earth-based telescope.

"We have acquired startlingly sharp images of the planet in a variety of filters, from the ultraviolet into the near infrared," said Cassini Imaging Science team leader Carolyn C. Porco of the University of Arizona.

The photo release has special significance for Porco - an acknowledged die-hard Beatles fan. "This is our first color image from Cassini and my gift to John Lennon - one of planet Earth's brightest stars, and a person who gave us all boundless joy, pleasure and inspiration," Porco said. "I am pleased that I can celebrate his birthday in this way," Porco said of the late Beatle. Lennon would have been 60 today.

CICLOPS, the Cassini Imaging Central Laboratory for Operations, is the hub of imaging team operations and is located in the Lunar and Planetary Laboratory at the University of Arizona in Tucson. CICLOPS houses the Cassini Imaging Diary, the entire collection of images that will document Cassini's travels over the next decade on its fly by Jupiter and into Saturn orbit for its four-year tour of the Saturn system.

Cassini is a joint mission of NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI). NASA's Jet Propulsion Laboratory manages the Cassini program for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.

Cassini-Huygens Portal
Related Links
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express

SPACE SCIENCE

Titan Probe Faces Restricted Communications Channel

Paris - October 5, 2000
During an extensive in-flight end-to-end telecommunications test conducted in early February 2000, characteristics of ESA's Huygens-Cassini communications link were observed which had not been previously measured. The test was a more extensive calibration at system level than the one which had previously been undertaken.

SPACE.WIRE