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 02.20.17

Airborne 02.20.17

Airborne 02.21.17

Airborne 02.22.17

Airborne 02.23.17

Airborne 02.17.17

Airborne-HD On YouTube

ADR 02.20.17

Airborne 02.20.17

Airborne 02.21.17

Airborne 02.22.17

Airborne 02.23.17

Airborne 02.17.17

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

Infamous RV-10 Lawsuit Against Van's Aircraft Dismissed

Years of Wasted Effort, Resources, and Worry Signal Ongoing Defects In US Tort Law When the news first came out, in 2015, that Van's Aircraft was sued for a considerable amount of >[...]

Airborne 02.22.17: CAF Dixie Wing P-63A, AF1 Price Cut, SLS Manned Flt?

Also: Drone Light Show, Remotely Piloted Helos, TFR Busts, Gulfstream, XTI Aircraft, CA Airlines, Icelandair After more than 40 years since it’s last flight, the Commemorativ>[...]

AMA Drone Report 02.20.17: DJI & AMA Team Up, MultiGP, Drone Advisory Committee

Also: Another Dumb FL Drone Law, AMA Expo East!, Spaceport America Drone Summit DJI and AMA have launched a joint program to promote safe and responsible drone operations, train pu>[...]

Airborne 02.21.17: NASA 'Space Poop' Challenge, Drone Advisory, Boeing

Also: Alphabet Balloons, Aero-Calendar, DJI-AMA, Solar Research, Dreamliners, F-35, ALPA NASA Johnson Space Center, in partnership with NASA Tournament Lab and online crowdsourcing>[...]

GA Aircraft Shipments And Billings Down Almost Across The Board

Only Uptick Was In Turboprop Airplanes, Turbine Helicopters Hit Hard The news is pretty much all bad, and some of it is really bad, in the GAMA 2016 year-end report of aircraft shi>[...]

blog comments powered by Disqus



Advertisement

Advertisement

Podcasts

Advertisement

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