Ganymede’s Polar Ice is ‘Disrupted’ by Jupiter’s Plasma

The first-ever infrared images of Ganymede’s north pole, taken on December 26, 2019 with the JIRAM instrument aboard NASA’s Juno spacecraft, show that the gigantic moon’s polar ice lacks any crystalline structure like the water ice we’re familiar with typically does here on Earth. This is a result of constant bombardment by charged plasma in…

When a Comet Met Ganymede

Captured by NASA’s Galileo spacecraft on April 5, 1997, this image shows Enki Catena, a 161.3-km (100-mile) long crater chain on the surface of Jupiter’s moon Ganymede. Named after the Sumerian god of fresh water, Enki Catena is thought to have been formed when a comet approached too close to Jupiter and was torn into 13 pieces, each impacting Ganymede in…

Ganymede Gets a Little Geologic Love

We don’t get to hear a lot about Ganymede these days, what with everyone paying so much attention to Titan and Enceladus and Europa and several other moons out there. Which is too bad because 1. Ganymede is plenty fascinating in its own right; and 2. it’s the LARGEST MOON IN THE SOLAR SYSTEM (and…

Titan is Drifting Away from Saturn Much Faster than We Thought

Recent research using data acquired by NASA’s Cassini spacecraft reveals that Titan is moving away from Saturn at a much faster rate than previously thought. How fast? Read on… “This result brings an important new piece of the puzzle for the highly-debated question of the age of the Saturn system and how its moons formed.”…

New Theory Emerges on the Formation of Jupiter’s Galilean Moons

(From Caltech) During the first few million years of our sun’s lifetime it was surrounded by a protoplanetary disk made up of gas and dust. Jupiter coalesced from this disk and became encircled by its own disk of satellite-building material. This “circum-Jovian disk” was fed by material from the sun’s protoplanetary disk that rained down…

Meet Metis – Jupiter’s Closest, Quickest Moon

Everyone’s heard of Jupiter’s four most famous moons Europa, Io, Callisto, and Ganymede—we’ve known about them for over 400 years, thanks to Galileo—but giant Jupiter has many more moons than that. To date there are thought to be 79 natural satellites orbiting Jupiter. So you’d be forgiven for not being immediately familiar with all of…

OSIRIS-REx Captures a Picture of Jupiter from L4

NASA’s OSIRIS-REx may be designed to study asteroids close up but recently it’s captured a view of something farther away and much, much larger: the giant planet Jupiter and three of its largest moons at a distance of over 400 million miles! The image was taken on Feb. 12, 2017, when the spacecraft was 76 million…

Eppur Si Muove: Galileo’s Big Night, 407 Years Ago Today

407 years ago tonight, on January 7, 1610, the Pisan astronomer Galileo Galilei looked up at a brilliantly-shining Jupiter through his own handmade telescope and saw three bright little “stars” next to it, stirring his natural scientific curiosity. Further observations over the next several nights showed that the planet wasn’t moving relative to the little “stars” as it…

Juno Just Hours from Jupiter Arrival

After nearly 5 years of traveling through space NASA’s Juno spacecraft is just a few dozen hours away from entering orbit around Jupiter, the Solar System’s largest, most massive, and most extreme planet. “We are ready,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute (SwRI). “The science team is incredibly excited…

Icy Enceladus Shines in the Latest Images from Cassini

On Wednesday, Oct. 14 2015, Cassini performed its scheduled “E-20” close pass of Enceladus, a 320-mile-wide moon of Saturn that is now famous for the organics-laden ice geysers that fire from cracks in its southern crust. E-20 is the first of a series of three flybys to be performed before the end of 2015, specifically timed to…