JUpiter ICy moon Explorer Archives

September 5, 2024September 9, 2024 by Matt Williams

Ouch! A Monster Asteroid Crashed Into Ganymede 4 Billion Years Ago, Rolling it Over

Artist's impression of the large impact that caused Ganymede to reorient itself 4 billion years ago. © HIRATA Naoyuki

Jupiter’s moon, Ganymede, is a fascinating celestial body. Measuring 5,268 km (3,272 mi) in diameter, it is also the largest satellite in the Solar System and even larger than Mercury, which measures 4,880 km (3,032 mi) in diameter. Like Europa, it has an interior ocean and is one of the few bodies in the Solar System (other than the gas giants) with an intrinsic magnetic field. The presence of this field also means Ganymede experiences aurorae circling the regions around its northern and southern poles due to interaction with Jupiter’s magnetic field.

In addition, based on its surface craters, scientists believe that Ganymede experienced a powerful impact with an asteroid about 4 billion years ago. This asteroid was about 20 times larger than the Chicxulub asteroid that caused the extinction of the dinosaurs, or the Cretaceous–Paleogene extinction event (ca. 66 million years ago). According to a recent study by Naoyuki Hirata of Kobe University, this impact occurred almost precisely on the meridian farthest away from Jupiter. This caused a reorientation of Ganymede’s rotational axis and allowed Hirata to determine exactly what type of impact took place.

November 19, 2023November 19, 2023 by Matt Williams

NASA Tests a Prototype Europa Lander

Testing Hardware for Potential Future Landing on Europa. Credit: NASA JPL-Caltech

In 2024, NASA will launch the Europa Clipper, the long-awaited orbiter mission that will fly to Jupiter (arriving in 2030) to explore its icy moon Europa. Through a series of flybys, the Clipper will survey Europa’s surface and plume activity in the hopes of spotting organic molecules and other potential indications of life (“biosignatures”). If all goes well, NASA plans to send a follow-up mission to land on the surface and examine Europa’s icy sheet and plumes more closely. This proposed mission is aptly named the Europa Lander.

While no date has been set, and the mission is still in the research phase, some significant steps have been taken to get the Europa Lander to the development phase. This past August, engineers at NASA’s Jet Propulsion Laboratory (JPL) in Southern California tested a prototype of this proposed landing system in a simulated environment. This system combines hardware used by previous NASA lander missions and some new elements that will enable a mission to Europa. It also could be adapted to facilitate missions to more “Ocean Worlds” and other celestial bodies in our Solar System.

October 18, 2021October 18, 2021 by Matt Williams

Europa has Water in its Atmosphere

Observations by the NASA/ESA Hubble Space Telescope recently revealed water vapour in the atmosphere of Ganymede, one of Jupiter’s moons. A new analysis of archival images and spectra has now revealed that water vapour is also present in the atmosphere of Jupter’s icy moon Europa. The analysis found that a water vapour atmosphere is present only on one hemisphere of the moon. This result advances our understanding of the atmospheric structure of icy moons, and helps lay the groundwork for upcoming science missions which will explore Jupiter’s icy moons.

Since the Voyager probes passed through the Jupiter system in 1979, scientists have been intrigued and mystified by its moon Europa. Once the images these probes acquired of the moon’s icy surface returned to Earth, scientists began to speculate about the possibility of a subsurface ocean. Since then, the detection of plume activity and other lines of evidence have bolstered this theory and fed speculation that there could be life beneath Europa’s icy surface.

According to new research, another critical piece of evidence of Europa’s watery nature has at least been confirmed. Using a similar technique that confirmed the presence of atmospheric water vapor in Jupiter’s moon Ganymede, Lorenz Roth of the KTH Royal Institute of Technology confirmed that Europa has water vapor in its atmosphere. This discovery could lead to a greater understanding of Europa’s atmosphere and surface environment, informing missions headed there in the near future.