Solar System

The little inner moon of Jupiter, Amalthea, isn’t dense enough.  A press release from Jet Propulsion Laboratory says that data from the Galileo spacecraft “shakes up long-held theories of how moons form around giant planets.”  Density of moons is supposed to decrease with radius around Jupiter, meaning that Amalthea should be the most solid.  Instead, […]

Several recent news stories touch on the uniqueness of Earth. Eccentric neighbors:  A story in Science Daily draws attention to the highly eccentric orbits of most extrasolar planets found so far.  The press release from Northwestern University begins, “Except for the fact that we call it home, for centuries astronomers didn’t have any particular reason […]

A press release from Jet Propulsion Laboratory announced the discovery of complex hydrocarbons in Titan’s atmosphere.  Some molecules have up to seven carbon atoms.  The discoveries came from the recent flyby on April 16, the closest yet, at just 638 miles above the surface.  Swooping into the upper layers of the atmosphere, the spacecraft came […]

All five observational and theoretical planetary scientists on a panel last week agreed that our solar system is a special place, reports Space.Com.  At the 5th annual Isaac Asimov Memorial Panel Debate, held at the American Museum of Natural History, the topic was “whether our solar system is special, why it looks the way it […]

Since its arrival at Saturn last June (see 07/01/2004 entry), the Cassini orbiter has achieved a string of phenomenal successes, and these just 15% of the way into its tour of Saturn’s rings, moons and magnetosphere (see JPL press release).  The prize has been publication of initial science results in Nature1 and Science2 – the […]

A week after the successful landing on Titan, ESA held its second main press conference on the findings.  The scientists were clearly upbeat about the results.  The probe transmitted data for 72 minutes from the surface after its 2.5 hour descent through the atmosphere.  The mesas, observed in stereo, are made of water ice about […]

Saturn has a moon named for the two-faced Roman god Janus, but the real two-faced moon is the larger Iapetus.  Since Jean Dominique Cassini discovered the moon in 1671 and noticed its varying brightness, scientists have been mystified by its two hemispheres, one as black as coal, the other white as snow.  Investigators were sure […]

At about 7:25 p.m. JPL time Christmas Eve, anxious scientists and engineers watching their monitors received bits from 800 million miles away, indicating that the Cassini spacecraft had successfully released the Huygens Probe over an hour earlier, with no faults or problems, right on schedule.  In mission control, engineers with Santa hats could be seen […]