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

AMA Drone Report

Airborne-Monday

Airborne-Tuesday

Airborne-Wednesday

Airborne-Thursday

Airborne-Friday

Airborne On ANN

ADR 01.23.17

Airborne 01.23.17

Airborne 01.24.17

Airborne 01.18.17

Airborne 01.19.17

Airborne 01.20.17

Airborne Hi-Def On YouTube

ADR 01.23.17

Airborne 01.23.17

Airborne 01.24.17

Airborne 01.18.17

Airborne 01.19.17

Airborne 01.20.17

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 01.23.17: PMA Approval Breakthrough, PBoR in Legal Ruling, R44 Cadet

Also: DJI Phantom 4, SpaceX Launch Vid, BasicMed AC, Rolls-Royce, Next F-35A Base, UAV Perched Ldg, K-MAX A proposed new compliance pathway for Parts Manufacturer Approval for manu>[...]

AMA Drone Report 01.23.17: AMA Expo West, Propel Star Wars Drones, Lily Folds

Also: Ready Made RC FPV Fest, ERAU Offering Drone Course, Second Drone Advisory Committee Meeting AMA Expo West was quite a transition for the ANN crew... who went from the insanit>[...]

Airborne 01.23.17: PMA Approval Breakthrough, PBoR in Legal Ruling, R44 Cadet

Also: DJI Phantom 4, SpaceX Launch Vid, BasicMed AC, Rolls-Royce, Next F-35A Base, UAV Perched Ldg, K-MAX A proposed new compliance pathway for Parts Manufacturer Approval for manu>[...]

Air Force COS Goldfein Addresses Priorities For The 21st Century

Outlines His Perspective For The Future Of American Air Power Air Force Chief of Staff Gen. David L. Goldfein outlined his perspective on the future of American airpower and how Ai>[...]

AeroSports Update: FAI World Glider Championship Results

The 34th FAI World Gliding Championships In Australia Ends On A High A hard two-week battle in Australian skies sees three new FAI Gliding World Champions win gold. Three new FAI G>[...]

blog comments powered by Disqus



Advertisement

Advertisement

Podcasts

Advertisement

© 2007 - 2017 Web Development & Design by Pauli Systems, LC