Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cassini Vims Team Finds That Phoebe May Be Kin To Comets

24.06.2004


Scientists have long doubted that Phoebe came from the same disk of material that formed Saturn and most of its moons. Phoebe has an unusual orbit that is inclined to Saturn’s equator, revolves backward with respect to both Saturn’s rotation and orbital motion, and travels in the opposite direction of Saturn’s other satellites.

Phoebe is widely believed to have wandered past Saturn and been captured by that planet’s mighty gravitational field. Where it wandered from was the question.

"All our evidence leads us to conclude that Phoebe’s surface is made of water ice, water-bearing minerals, carbon dioxide, possible clays and primitive organic chemicals in different locations on the surface," VIMS team member Roger N. Clark of the U.S. Geological Survey in Denver said a few days after the flyby. "We also see spectral signatures of materials that we have not yet identified."



It is clear that the materials in Phoebe’s surface bear little resemblance to the predominantly rocky material found in asteroids in the belt between Mars and Jupiter. The materials that make up Phoebe formed farther out in the solar system, where it is cold enough for them to remain stable.

"One intriguing result of the VIMS measurements is the discovery of possible chemical similarities between the materials on Phoebe and those seen on comets," said VIMS team leader Robert H. Brown of the University of Arizona.

Short period comets are thought to sit among other primitive solar system debris in the Kuiper belt, until tugged by Neptune’s gravity toward the inner solar system. Evidence that Phoebe might be chemically kin to comets strengthens the case that it’s similar to Kuiper Belt Objects.

The VIMS instrument is an imaging spectrometer that produces a special data set called an image cube. It takes an image of an object in many colors simultaneously. An ordinary video camera takes images in three primary colors (red, green, and blue) and combines them to produce images as seen by the human eye. The VIMS instrument takes images in 352 separate colors, spanning a realm of colors far beyond those visible to humans. All materials reflect light in a unique way. So molecules of any element or compound can be identified by the colors they reflect or absorb, their "signature" spectra. The VIMS team knew the basic chemical make-up of Phoebe only a few days after flyby.

That Phoebe likely comes from the Kuiper belt and not from the Mars-Jupiter asteroid belt is another "first" for the Cassini mission, Brown noted. Cassini has become the first spacecraft to flyby a Kuiper belt object, he said.

Cassini flew by Phoebe on June 11. Cassini will conduct a critical 96-minute main-engine burn before going into orbit around Saturn on June 30 (July 1 Universal Time). During Cassini’s planned four-year tour it will conduct 76 orbits around the Saturn system and execute 52 close encounters with seven of Saturn’s 31 known moons.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The VIMS team is based at the University of Arizona in Tucson.

Lori Stiles | UA science news
Further information:
http://www.arizona.edu
http://wwwvims.lpl.arizona.edu

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>