Icy Jupiter Moon Throws a Curve Ball at Formation Theories | Aero-News Network
Aero-News Network
RSS icon RSS feed
podcast icon MP3 podcast
Subscribe Aero-News e-mail Newsletter Subscribe

Airborne Unlimited -- Recent Daily Episodes

Episode Date

Monday

Tuesday

Wednesday

Thursday

Friday

Airborne On ANN

Airborne 06.29.15

Airborne 06.30.15

Airborne 07.01.15

Airborne 06.25.15

Airborne 06.26.15

Airborne Hi-Def On YouTube

Airborne 06.29.15

Airborne 06.30.15

Airborne 07.01.15

Airborne 06.25.15

Airborne 06.26.15

Wed, Jun 01, 2005

Icy Jupiter Moon Throws a Curve Ball at Formation Theories

Say, Where Did THAT Come From?

Scientists studying data from NASA's Galileo spacecraft have found that Jupiter's moon Amalthea is a pile of icy rubble less dense than water. Scientists expected moons closer to the planet to be rocky and not icy. The finding shakes up long-held theories of how moons form around giant planets.

"I was expecting a body made up mostly of rock. An icy component in a body orbiting so close to Jupiter was a surprise," said Dr. John D. Anderson, an astronomer at NASA’s Jet Propulsion Laboratory, Pasadena, CA. Anderson is lead author of a paper on the findings that appears in the current issue of the journal Science.

"This gives us important information on how Jupiter formed, and by implication, how the solar system formed," Anderson said.

Current models imply that temperatures were high at Amalthea's current position when Jupiter’s moons formed, but this is inconsistent with Amalthea being icy. The findings suggest that Amalthea formed in a colder environment. One possibility is that it formed later than the major moons. Another is that the moon formed farther from Jupiter, either beyond the orbit of Jupiter's moon Europa or in the solar nebula at or beyond Jupiter's position. It would have then been transported or captured in its current orbit around Jupiter. Either of these explanations challenges models of moon formation around giant planets.

"Amalthea is throwing us a curve ball," said Dr. Torrence Johnson, co-author and project scientist for the Galileo mission at JPL. "Its density is well below that of water ice, and even with substantial porosity, Amalthea probably contains a lot of water ice, as well as rock." Analysis of density, volume, shape and internal gravitational stresses lead the scientists to conclude that Amalthea is not only porous with internal empty spaces but also contains substantial water ice.

One model for the formation of Jupiter's moons suggests that moons closer to the planet would be made of denser material than those farther out. That is based on a theory that early Jupiter, like a weaker version of the early Sun, would have emitted enough heat to prevent volatile, low-density material from condensing and being incorporated into the closer moons. Jupiter's four largest moons fit this model, with the innermost of them, Io, also the densest, made mainly of rock and iron.

Amalthea is a small red-tinted moon that measures about 168 miles in length and half that in width. It orbits about 181,000 kilometers (112,468 miles) from Jupiter, considerably closer than the Moon orbits Earth. Galileo passed within about 99 miles of Amalthea on Nov. 5, 2002. Galileo's flyby of Amalthea brought the spacecraft closer to Jupiter than at any other time since it began orbiting the giant planet on Dec. 7, 1995. After more than 30 close encounters with Jupiter's four largest moons, the Amalthea flyby was the last moon flyby for Galileo.

The Galileo spacecraft's 14-year odyssey came to an end on Sept. 21, 2003. JPL, a division of the California Institute of Technology in Pasadena, managed the Galileo mission for NASA.

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

Advertisement

More News

Airborne 06.30.15: Defending Santa Monica, Aspen ADS-B, NBAA v Privatization

Also: Spectra Reserves, Aero-Calendar, New Airman Standards, Spaceport America, Pointing Lasers, C-17 Training Network, Seaplane Sim Supporters of the Santa Monica, California Airp>[...]

Hexacopter Blasted Out Of The Air Results In Small Claims Charge

Court Finds In Favor Of Aircraft Owner Back in November last year, Eric Joe was visiting his parent's home in Modesto, CA, and flew his Hexacopter low and slow over what he says wa>[...]

SpaceX Falcon 9 Anomaly Was Apparently In The Booster's Second Stage

First Stage Operated Normally As The Spacecraft Disintegrated More details are emerging from the launch failure Sunday of a SpaceX Falcon 9 booster carrying a Dragon resupply space>[...]

AeroSports Update: Wingfoot One Headed To AirVenture

Goodyear’s Brand New Wingfoot One Airship Makes Its EAA AirVenture Oshkosh Debut This Year. If you think rigid airships are something from the past, it’s time to get a >[...]

AD: Dassault Aviation Airplanes

AD NUMBER: 2015-13-08 PRODUCT: All Dassault Aviation Model FALCON 2000EX airplanes.>[...]

blog comments powered by Disqus



Advertisement

Advertisement

Podcasts

Advertisement

© 2007 - 2015 Web Development & Design by Pauli Systems, LC