Cassini Exposes Saturn's Two-Face Moon | Aero-News Network
Aero-News Network
RSS icon RSS feed
podcast icon MP3 podcast
Subscribe Aero-News e-mail Newsletter Subscribe

** Airborne 04.18.14--CLICK HERE! ** HD iPad-Friendly Version--Airborne 04.18.14 **
** Airborne 04.16.14--CLICK HERE! ** HD iPad-Friendly Version--Airborne 04.16.14 **
** Airborne 04.14.14--CLICK HERE! ** HD iPad-Friendly Version--Airborne 04.14.14 **

Fri, Jul 16, 2004

Cassini Exposes Saturn's Two-Face Moon

From JPL...

The moon with the split personality, Iapetus, presents a perplexing appearance in the latest images snapped by the Cassini spacecraft.

One hemisphere of the moon is very dark, while the other is very bright. Scientists do not yet know the origin of the dark material or whether or not it is representative of the interior of Iapetus.

Iapetus (pronounced eye-APP-eh-tuss) is one of Saturn's 31 known moons. Its diameter is about one third that of our own moon at 1,436 kilometers (892 miles). This image was taken in visible light with the Cassini spacecraft narrow angle camera on July 3, 2004, from a distance of 3 million kilometers (1.8 million miles) from Iapetus. The brightness variations in this image are not due to shadowing, they are real.

During Cassini's four-year tour, the spacecraft will continue to image Iapetus and conduct two close encounters. One of those encounters, several years from now, will be at a mere 1,000 kilometers (622 miles).

Iapetus was discovered by the Italian-French astronomer Jean Dominique Cassini in 1672. He correctly deduced that the trailing hemisphere is composed of highly reflective material, while the leading hemisphere is strikingly darker.

This sets Iapetus apart from Saturn's other moons and Jupiter's moons, which tend to be brighter on their leading hemispheres. Voyager images show that the bright side of Iapetus, which reflects nearly 50 percent of the light it receives, is fairly typical of a heavily cratered icy satellite. The leading side consists of much darker, redder material that has a reflectivity of only about 3 to 4 percent.

One scenario for the outside deposit of material has dark particles being ejected from Saturn's little moon Phoebe and drifting inward to coat Iapetus. One observation lending credence to an internal origin is the concentration of material on crater floors, which is suggestive of something filling in the craters. 

Iapetus is odd in other respects. It is in a moderately inclined orbit, one that takes it far above and below the plane in which the rings and most of the moons orbit. It is less dense than many of the other satellites, which suggests a higher fraction of ice or possibly methane or ammonia in its interior.

FMI: http://saturn.jpl.nasa.gov

Advertisement

More News

Aero-News: Quote Of The Day (04.20.14)

"The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth. Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James >[...]

Skydive Jersey Announces Shuttle Service For 2014 Season

Removes 'Getting To The Airport' As An Excuse To Not Go Skydiving So imagine it's a beautiful day to go jump out of an airplane in the greater New York City area, but you just don'>[...]

ANN's Daily Aero-Term (04.20.14): Ground Stop

Ground Stop Ground Stops are implemented for a number of reasons. The most common reasons are: 1) To control air traffic volume to airports when the projected traffic demand is exp>[...]

ANN's Daily Aero-Linx (04.20.14)

Aero Linx: The Australian Parachute Federation The Australian Parachute Federation exists to administer and represent Australian Sport Parachuting. This is achieved by promoting an>[...]

ANN FAQ: Getting The Most Out Of ANN's Newsletters

ANN goes through a lot of trouble to make the graphics flashy and cool and an integral part of the story. But let's face it, they're bandwidth-intensive. So here are a couple of th>[...]

blog comments powered by Disqus



Advertisement

Advertisement

Podcasts

Advertisement

© 2007 - 2014 Web Development & Design by Pauli Systems, LC