Jupiter Archives

February 20, 2023February 20, 2023 by Matt Williams

All of Jupiter's Large Moons Have Auroras

Artist's concept of aurorae on Ganymede - auroral belt shifting may indicate a subsurface saline ocean. Credit: NASA/ESA

Jupiter is well known for its spectacular aurorae, thanks in no small part to the Juno orbiter and recent images taken by the James Webb Space Telescope (JWST). Like Earth, these dazzling displays result from charged solar particles interacting with Jupiter’s magnetic field and atmosphere. Over the years, astronomers have also detected faint aurorae in the atmospheres of Jupiter’s largest moons (aka. the “Galilean Moons“). These are also the result of interaction, in this case, between Jupiter’s magnetic field and particles emanating from the moons’ atmospheres.

Detecting these faint aurorae has always been a challenge because of sunlight reflected from the moons’ surfaces completely washes out their light signatures. In a series of recent papers, a team led by the University of Boston and Caltech (with support from NASA) observed the Galilean Moons as they passed into Jupiter’s shadow. These observations revealed that Io, Europa, Ganymede, and Callisto all experience oxygen-aurorae in their atmospheres. Moreover, these aurorae are deep red and almost 15 times brighter than the familiar green patterns we see on Earth.

February 14, 2023February 14, 2023 by Andy Tomaswick

Why are Jupiter’s Trojan Regions so Unevenly Balanced With Asteroids?

Solar systems evolve, especially early on in their lifetimes. While this evolution is primarily driven by gravity, there are some parts of our own solar system that are difficult to understand – especially how gravity forced them into their current configuration. One of the most prominent of these areas is the Trojan asteroids.

February 8, 2023February 8, 2023 by Nancy Atkinson

New Discoveries Puts Jupiter at 92 Known Moons

A top-down overhead view of the orbits of Jupiter's 92 moons. Credit: Scott Sheppard.

The moon hunter strikes again.

A team of astronomers led by Scott Sheppard of the Carnegie Institution has found and confirmed 12 new moons orbiting Jupiter, bringing the total of moons at the giant planet to 92. The new moons were quietly announced on the International Astronomical Union’s Minor Planet Center website last week, and the new discoveries puts Jupiter in the lead in a recent back-and-forth moon battle with Saturn.

Jupiter was solidly in the lead with Sheppard and team’s announcement of 12 new moons back in 2018, but then in 2019, Sheppard and colleagues found a whopping 20 new moons orbiting Saturn, bringing the ringed planet’s total number of moons to 82. But now this latest addition moves Jupiter back in the lead.

With Sheppard around, we may never know the final count.

December 29, 2022December 29, 2022 by Carolyn Collins Petersen

An Ongoing Study of Jupiter’s Cloudtops Has Been Going on for 40 Years

A Hubble Space Telescope image of Jupiter in 2020. Planetary scientists studied temperature changes in its lower atmosphere and may soon be able to predict Jupiter weather. Credit: NASA, ESA, A. Simon (Goddard Space Flight Center), and M. H. Wong (University of California, Berkeley) and the OPAL team.

Some of the most useful discoveries about distant objects take time to complete. For example, several generations of planetary scientists have been studying the clouds of Jupiter since the late 1970s. Their observations focused on the planet’s upper troposphere. The results show unexpected patterns in how the temperatures of Jupiter’s belts and zones change over time.

December 16, 2022March 4, 2023 by Carolyn Collins Petersen

Juno has Been Touring Jupiter’s Moons on its Extended Mission. Next Stop: Volcanic Io

The Juno mission's infrared view of the Jovian moon Io. Taken on July 5, 2022. All the hotspots are volcanic features. Courtesy NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

For a tiny moon orbiting a giant planet, Io sure packs a giant wallop. It’s the most volcanic world in the solar system. Due to that extreme volcanism, scientists with the Juno mission are now focusing the spacecraft’s instruments and cameras on Io. They want to know more about its eruptions and how its constant stream of material into space interacts with Jupiter’s magnetosphere.

October 14, 2022October 14, 2022 by Andy Tomaswick

New Views of Ganymede and Europa From Earth’s Most Powerful Telescope

Scouting mission locations in the outer solar system is complicated. It is difficult to know what you find before you get there with a probe, and once you’re already there, changing trajectories to look at the most exciting parts of the system is difficult. A much better option would be to map out the system in detail before the probe arrives. That is precisely what a team at the University of Leicester is doing in the expectation of the arrival of the JUICE and Europa Clipper probes to the Jupiter system.

October 13, 2022October 13, 2022 by Nancy Atkinson

Mars Express Watched Deimos Pass in Front of Jupiter and its Moons

That’s no moon … wait … yes, it is, and more!

ESA’s Mars Express has captured an unusual and rare occultation, all from its vantage point in orbit of Mars. The spacecraft’s orbit brought it to the right place where it could witness the moment Mars’ small moon Deimos passed in front of Jupiter and its four largest moons. Scientists say that celestial alignments like these enable a more precise determination of the Martian moons’ orbits.

September 28, 2022September 28, 2022 by Brian Koberlein

Jupiter’s Atmosphere is Surprisingly Hot

Temperature measurements of Jupiter's upper atmosphere. Credit: James O’Donoghue

Jupiter is a big planet, but it’s still a planet. That means it doesn’t heat itself through fancy mechanisms like nuclear fusion. Its interior is heated through its own weight, squeezing the interior through hydrostatic equilibrium, and its surface is heated mostly by the Sun. Since Jupiter only gets about 4% of the light per square meter that Earth gets, you’d expect its upper atmosphere to be pretty cold. Traditional models estimate it should be about -70 degrees Celsius. But recent measurements show the upper atmosphere is over 400 degrees Celsius, and in the polar regions as much as 700 degrees Celsius. In the words of Ruby Rhod from the movie The Fifth Element, “It’s Hot Hot Hot!”

September 28, 2022September 28, 2022 by Matt Williams

A Fascinating Look at Jupiter's Clouds Where the Light Intensity is Converted Into 3D

A still image from the 3D animation that shows the elevation of Jupiter's cloud tops. Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt

In July 2016, NASA’s Juno space probe reached Jupiter, becoming the second spacecraft in history to orbit the gas giant (the first being the Galileo probe that orbited Jupiter from 1995 to 2003). The data it has sent back has led to new revelations about the Jovian atmosphere, magnetosphere, gravitational field, structure, and composition. While its primary mission was intended to only last until 2018, a mission extension means that Juno will continue to orbit Jupiter’s poles (a perijove maneuver) and send back stunning images and data until 2025.

Recently, a team of citizen scientists led by mathematician and software developer Gerald Eichstädt used images taken by the probe’s visible-light camera/telescope (the JunoCam) to create a 3D animation of Jupiter’s upper atmosphere. Eichstädt’s animation was presented at the 2022 Europlanet Science Congress (EPSC), which took place from September 18 – 23 in Granada, and shows the relative heights of the cloud tops of Jupiter that reveal delicately textured swirls and peaks. Eichstädt’s work also showcased the potential for citizen science and public engagement with today’s missions.

August 22, 2022August 22, 2022 by Alan Boyle

Webb Telescope Sees Jupiter and Its Auroras in a New Light

JWST view of Jupiter — The James Webb Space Telescope's NIRCam imager produced this composite image of the Jupiter system using orange and cyan filters. The image shows Jupiter's auroras as bright rims at the poles. The planet's rings and two of its moons, Amalthea and Adrastea, are also visible. Credit: NASA, ESA, CSA, Jupiter ERS Team; image processing by Ricardo Hueso (UPV/EHU) and Judy Schmidt.

NASA’s James Webb Space Telescope is designed to probe the farthest frontiers of the universe, but newly released images of Jupiter prove that the observatory can also bring fresh perspectives to more familiar celestial sights.

The infrared images reveal Jupiter’s polar auroras and its faint rings as well as two of its moons — plus some galaxies in the far background. The planet’s Great Red Spot is there as well, but because it’s seen through three of JWST’s specialized filters, it looks white rather than red.

JWST’s new perspective should give scientists a better sense of how the complex Jupiter system is put together.