A Naked Titan Revealed by 13 Years of Cassini Data

Saturn’s largest moon Titan boasts the distinction of being the only moon in the solar system to have a thick atmosphere…so thick, in fact, that its surface is perpetually hidden from our view—but not from the view of the Cassini spacecraft’s infrared cameras! Cassini, now over ten months gone after its Sept. 2017 plunge into…

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…

ESA Grabs Glimpses of Mars’ Groovy Moon

This animation is comprised of three images acquired by ESA’s Mars Express spacecraft on Sept. 12, 2017 with its High Resolution Stereo Camera (HRSC). It shows parts of the grooved and pitted surface of Phobos, the larger of Mars’ two natural satellites. The original images were captured in greyscale; I added color based on other…

THEMIS Takes Deimos’ Temperature

Can you feel the heat? NASA’s Mars Odyssey can see it! This is an image of Mars’ smaller moon Deimos, captured with Odyssey’s THEMIS (Thermal Emission Imaging System) instrument on Feb. 15, 2018. Part of the 7-mile-wide Moon was in shadow, but the sunlit surface area reached temperatures up to 200 K (that’s still pretty…

Have No Fear, Phobos is Here!

On May 12, 2016, the Hubble Space Telescope captured a series of images of Mars and in them the planet’s moon Phobos can be seen appearing from behind the western limb. This was just 10 days before opposition which, in 2016, was the closest Mars had been to Earth since 2005, lending particularly good opportunity…

These Are Our Best Pictures of Mars’ Smallest Moon

Mars isn’t a planet well-known for its natural satellites but it actually does have two small moons. The larger, Phobos, is an irregularly-shaped, heavily grooved and cratered world only about 17 miles (27 km) across at its widest. It orbits Mars so closely that it completes 3 orbits every day, and isn’t even visible from…

This is Jupiter Seen from Mars

The HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter (MRO) is specifically designed to take super high-resolution images of the surface of Mars but it also does a pretty darn good job capturing pictures of other objects too—like Jupiter and its Galilean moons, several hundred million miles away! The image above was captured in expanded color (that is,…

Hail Hydra: Pluto’s Moon is Covered in Almost Pure Water Ice

Discovered in June 2005, distant Pluto’s outermost moon Hydra it thought to have formed during the same collision four billion years ago that created the Pluto-Charon system that we see today. Yet despite its age this 31-mile (50-km) -long moon appears remarkably clean and bright,  as witnessed by New Horizons during its close pass through the Pluto system in July 2015.

A New Moon is Discovered in the Solar System

Turns out there is something new under the Sun, at least to us; on Tuesday, April 26 scientists announced the discovery of a new moon in the Solar System—but it’s not around Earth, or Jupiter, or Saturn, or any of the planets that you’ve long been familiar with. This new moon is orbiting a distant world even…

Europa’s Icy Crust May Be Warmer Than We Thought

All the worlds may be ours except Europa but that only makes the ice-covered moon of Jupiter all the more intriguing. Beneath Europa’s thin crust of ice lies a tantalizing global ocean of liquid water somewhere in the neighborhood of 100 kilometers deep—which adds up to more liquid water than is on the entire surface of the Earth. Liquid…

Cassini Has Made Its Last Pass by Enceladus. Here Are the Pictures.

After nearly eleven and a half years in orbit around Saturn the Cassini spacecraft has made its last-ever targeted flyby of Enceladus, the 320-mile-wide moon of Saturn that has intrigued scientists and the public alike with its active water ice geysers for more than a decade since their discovery. On Saturday Dec. 19, 2015, Cassini performed its E-22…