Thank you for signing up to Space. Officials are hoping to send a probe to Europa by the mid-2020s. Ganymede is named for a boy who was made cupbearer for the ancient Greek gods by Zeus – Jupiter to the Romans. The magnetic field causes auroras, which are ribbons of glowing, electrified gas, in regions circling the moon’s north and south poles. (Image credit: NASA, ESA, and A. Feild (STScI)). JPL is managed by the California Institute of Technology in Pasadena for NASA. unknown origin. With the presence of the subsurface ocean, just like Europa (the fourth largest moon of Jupiter), scientists are considering Ganymede as a serious prospect for extraterrestrial life. The scenario that best fits the data is a melted layer of water as salty as Earth's oceans and several kilometers thick, starting about 200 kilometers down. Are you in? [94] The accretion of Ganymede probably took about 10,000 years,[95] much shorter than the 100,000 years estimated for Callisto. [23][77] The magnetic field detected around Ganymede is likely to be caused by compositional convection in the core,[77] if the magnetic field is the product of dynamo action, or magnetoconvection.

As the oceans churn and cold plumes snake around, ice in the uppermost ocean layer, called "Ice III," could form in the seawater. "Bright broken swaths, disrupted dark plains and the astounding Arbela Sulcus suggest Ganymede may be more similar to Europa than previously believed," says Brown University's Robert Pappalardo.
[23] Its existence is connected with the variation of the Jovian magnetic field near Ganymede. Europa has a much higher proportion of rock to ice than Ganymede does, and is also warmer because of greater tidal friction; the same physics that predicted Ganymede's perched-ocean-within-an-icy-mantle predicts that Europa's liquid water ocean is in direct contact with its warm rocky core. NASA Hubble Space Telescope images of Ganymede's auroral belts (colored blue in this illustration) lie on top of a Galileo orbiter image of the moon. [23] Its north pole lies below the orbital plane. Ganymede /ˈɡænɪmiːd/, a satellite of Jupiter (Jupiter III), is the largest and most massive of the Solar System's moons. Some super-Earths, rocky planets more massive than Earth, have been proposed as "water worlds" covered in oceans. NASA also has its eye on the Jupiter system. Juno spacecraft orbits Jupiter and is Researchers were able to watch the two auroras "rock" back and forth with Hubble. [102] The convective motions in Callisto have caused only a partial separation of rock and ice.

The amount of rocking of the moon's magnetic field supplied evidence that the moon possesses a subsurface saltwater ocean. ESA's contribution faced funding competition from other ESA projects,[113] but on 2 May 2012 the European part of the mission, renamed Jupiter Icy Moon Explorer (JUICE), obtained a L1 launch slot in 2022 with an Ariane 5 in the ESA's Cosmic Vision science programme. The featured image was taken about 20 years ago by NASA's Galileo probe, which ended its mission by diving into Jupiter's atmosphere in 2003.

This "snow" melts again before reaching the top of the ocean, possibly leaving slush in the middle of the moon sandwich. The only evidence to date was collected during brief flybys with … Two other Jovian moons, Europa and Callisto, are also believed to harbor subterranean seas. NASA scientists first suspected an ocean in Ganymede in the 1970s, based on models of the large moon, which is bigger than Mercury. The ice can become so dense that it is heavier than water and falls to the bottom of the sea. But if you don't insist that everything have to do with life to be cool, then this is a very cool result. JUICE is expected to check out Europa, Callisto and Ganymede during its mission. The induced moment is directed radially to or from Jupiter following the direction of the varying part of the planetary magnetic field. However, the matter is very much skeptical because of its internal structure where the pressure of the ocean is so high that would convert any water down there into ice. New York, In this artist’s conceptual illustration, the moon Ganymede orbits giant planet Jupiter. What does the largest moon in the The surface number density and pressure were calculated from the column densities reported in Hall, et al. Could they have life? [68] In this respect, Ganymede is different from Callisto, which apparently failed to melt and differentiate early due to loss of the accretional heat during its slower formation.

[116], A Ganymede orbiter based on the Juno probe was proposed in 2010 for the Planetary Science Decadal Survey. "Ganymede's ocean might be organized like a Dagwood sandwich," said Steve Vance of NASA's Jet Propulsion Laboratory in Pasadena, Calif., explaining the moon's resemblance to the "Blondie" cartoon character's multi-tiered sandwiches. Vance and his team showed, through laboratory experiments, how much salt really increases the density of liquids under the extreme conditions inside Ganymede and similar moons. In the 1990s, NASA's Galileo mission flew by Ganymede, confirming the moon's ocean, and showing it extends to depths of hundreds of miles. "Ganymede’s ocean might be organized like a Dagwood sandwich," said Steve Vance of NASA's Jet Propulsion Laboratory in Pasadena, Calif., explaining the moon's resemblance to the "Blondie" cartoon character's multi-tiered sandwiches. Scientists have also found strong evidence of an underground ocean on Ganymede. If the ratio is unity, then the resonance is the Laplace resonance. [120] Another old proposal was called The Grandeur of Ganymede. Accelerate progress in our three core enterprises — Explore Worlds, Find Life, and Defend Earth. Of course, Ganymede is a very big world, so "relatively small" in this case can mean an ocean up to about 100 kilometers deep.

(For a lot more on the funky layered forms that liquid and solid water could take at Ganymede, read my writeup of Steve Vance's work on Ganymede's internal layering, which he presented at the Lunar and Planetary Science conference two years ago.). The spacecraft also found evidence for salty seas, likely containing the salt magnesium sulfate. Solar System’s Largest Moon Likely Has a Hidden Ocean Add Jupiter’s moon Ganymede, which is bigger than two of the solar system’s nine planets, to the growing list of worlds with evidence of liquid water under the surface.

Image released March 12, 2015. This artist's concept of Jupiter's moon Ganymede, the largest moon in the solar system, illustrates the "club sandwich" model of its interior oceans. Several probes flying by or orbiting Jupiter have explored Ganymede more closely, including four flybys in the 1970s, and multiple passes in the 1990s to 2000s. [107], In 1995, the Galileo spacecraft entered orbit around Jupiter and between 1996 and 2000 made six close flybys to explore Ganymede. Margaret Kivelson and coworkers described evidence for it from Galileo magnetometer data in 2002. [49] The most recent close observations of Ganymede were made by New Horizons, which recorded topographic and compositional mapping data of Europa and Ganymede during its flyby of Jupiter in 2007 en route to Pluto. Our citizen-funded spacecraft successfully demonstrated solar sailing for CubeSats. Because aurorae are controlled by the magnetic field, if you observe the aurorae in an appropriate way, you learn something about the magnetic field. Scientists have also found that Ganymede's surface shows signs of flooding. The field strength of the induced field at the magnetic equator is about 60 nT—half of that of the ambient Jovian field. [77] The current heat flux out of Ganymede is probably higher than that out of Callisto.[96]. ocean layer that contains

Receive mail from us on behalf of our trusted partners or sponsors? The study, led by Vance, provides new theoretical evidence for the team's "club sandwich" model, first proposed last year. The European Space Agency is planning to send a probe called JUICE — short for JUpiter ICy moons Explorer — to Jupiter and its moons in 2022. The heavier salts would thus fall downward, and the lighter ice, or "snow," would float upward. Previously, the moon was thought to harbor a thick ocean sandwiched between just two layers of ice, one on top and one on bottom. Future US, Inc. 11 West 42nd Street, 15th Floor, [105], Voyager 1 and Voyager 2 were next, passing by Ganymede in 1979. And new photos that Galileo snapped of Ganymede from within 809 kilometers in May hint at just those sorts of cracks. Receive news and offers from our other brands? Scientists might be able to search for rocking auroras on exoplanets that could potentially harbor water using the lessons learned from the Hubble observations of Ganymede. Learn how our members and community are changing the worlds. Interiors of icy bodies in the solar system (as of 2010), Three simplified models for Pluto’s interior, read the writeup at the Space Telescope Science Institute website, past work on the internal structure of Ganymede, read my writeup of Steve Vance's work on Ganymede's internal layering, one of the Cassini instrument teams announced that they had detected rock particles from just such an environment that originated within Enceladus, Did Scientists Just Find Life on Venus? [23][92], Despite the presence of an iron core, Ganymede's magnetosphere remains enigmatic, particularly given that similar bodies lack the feature. [70] The decay of radioactive elements within rocks further heated the core, causing increased differentiation: an inner, iron–iron-sulfide core and a silicate mantle formed. The ocean on Ganymede — which is buried under a thick crust of ice — could actually harbor more water than all of Earth's surface water combined, according to NASA officials.

Here are instructions on how to enable JavaScript in your web browser. "The solar system is now looking like a pretty soggy place," Jim Green, NASA's director of planetary science, said during a news teleconference today (March 12). The rocks settled to the center, forming the core. [96] The mantle, in turn, transported it to the surface by convection.
They refined its size, revealing it was larger than Saturn's moon Titan, which was previously thought to have been bigger. "I was always brainstorming how we could use a telescope in other ways," Joachim Saur, geophysicist and team leader of the new finding, said in a statement. This cross-sectional illustration shows the interior of Jupiter's largest moon Ganymede, based on theoretical models, in-situ observations by NASA's Galileo orbiter, and Hubble Space Telescope observations of the moon’s magnetosphere. It's the least dense form of ice and lighter than water. Ganymede has large, bright regions of ridges and grooves that slice across older, darker terrains. You will receive a verification email shortly. [104] Pioneer 10's closest approach was 446,250 km. Recent evidence that Ganymede, the solar system's largest moon, may hide an ocean beneath its surface is less surprising than news of water on Mars. Aurorae on Ganymede—auroral belt shifting may indicate a subsurface saline ocean. The induced magnetic moment is an order of magnitude weaker than the intrinsic one.

Still, it's very cool to have an independent way of confirming that Ganymede does have an internal ocean, and that's what was published today, in an article by Joachim Saur and 13 coauthors. That is a lot of liquid water, but it's in a very different place within Ganymede than the liquid water that we think exists at Europa and Enceladus. It's wonderful that we can use an Earth-based telescope to look at the aurorae of a giant planet moon to deduce the presence of an ocean that we can't see. "We're changing the world. Scientists used Hubble to monitor Ganymede's auroras, ribbons of light at the poles created by the moon's magnetic field. In the 1990s, NASA's Galileo mission flew by Ganymede, confirming the moon's sub-surface ocean. Like Earth's Moon, Ganymede keeps the Hidden ocean. [90] The Ganymedian magnetosphere has a region of closed field lines located below 30° latitude, where charged particles (electrons and ions) are trapped, creating a kind of radiation belt. Galileo Regio,