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…

More Evidence for Plumes of Water on Jupiter’s Icy Moon Europa

All those worlds may be ours except Europa but that doesn’t make the ice-covered moon of Jupiter any less intriguing. Beneath Europa’s crisscrossed crust lies a tantalizing ocean somewhere in the neighborhood of 100 kilometers deep—which adds up to more liquid water than on the entire surface of the Earth. Liquid water plus a heat source(s) to keep it…

Newly Reprocessed Images of Europa Show ‘Chaos Terrain’ in Crisp Detail

(Via NASA) The surface of Jupiter’s moon Europa features a widely varied landscape, including ridges, bands, small rounded domes and disrupted spaces that geologists call “chaos terrain.” Three newly reprocessed images, taken by NASA’s Galileo spacecraft in the late 1990s, reveal details in diverse surface features on Europa. Although the data captured by Galileo is…

A Twisted Towel of Bright Clouds on Jupiter

This dramatic image, a color-composite I made from raw data captured by NASA’s Juno spacecraft, shows a bright band of high-altitude clouds on Jupiter’s northern hemisphere on July 16, 2018. Because of the abstract nature of Jupiter’s atmosphere in general (and a fun little phenomenon called pareidolia) one could find many different shapes in this…

Ten More Moons For Jupiter!

Jupiter is the reigning heavyweight among the planets in our solar system so it just makes sense that it also possesses the most natural satellites. Over the past year I have been gleefully telling people that Jupiter has 69 moons (usually to a shocked response, occasionally to a giggling one) but now I must admit…

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 69 natural satellites orbiting Jupiter. 53 are officially named, while 16 are awaiting further confirmation. So you’d…

Surprise! Jupiter’s Poles are Literally Encircled by Cyclones

If you think that Saturn’s polar storm systems are amazing then you’re gonna love this: Jupiter has them too, and not just a single central storm over each of its poles either. NASA’s Juno mission has revealed that Jupiter has not only polar vortices but also a ring of enormous cyclones spinning in formation around…

Eppur Si Muove: Galileo’s Big Night

On this night in 1610 the Pisan astronomer Galileo Galilei looked up at a bright Jupiter at opposition through his handmade telescope and noted three little “stars” next to it, piquing his natural scientific curiosity. Further observations over the next few nights showed that the planet wasn’t moving relative to the little “stars” as it…