Heres how it works. [17][73] Europa's surface temperature averages about 110K (160C; 260F) at the equator and only 50K (220C; 370F) at the poles, keeping Europa's icy crust as hard as granite. The Galilean moons. Callisto orbits Jupiter at a distance of about 1,168,000 miles (1,880,000 kilometers). The Galilean moons ( or Galilean satellites) are the four largest moons of JupiterIo, Europa, Ganymede, and Callisto. [21] Io is anhydrous and likely has an interior of rock and metal. The color of the markings, reddish-brown, is theorized to be caused by sulfur, but scientists cannot confirm that, because no data collection devices have been sent to Europa. January 2022: The Next Full Moon is the Wolf Moon, or Ice Moon. The name comes from a mythical Phoenician noblewoman, Europa, who was courted by Zeus and became the queen of Crete, though the name did not become widely used until the mid-20th century. Distance from Jupiter: It is the outermost of the Galilean moons. [10] However, because he did not publish these findings until after Galileo, there is a degree of uncertainty around his records.[10]. Callisto orbits Jupiter at a distance of . Most geologists who have studied Europa favor what is commonly called the "thick ice" model, in which the ocean has rarely, if ever, directly interacted with the present surface. S/2010 J 2 has a diameter of about 1.2 miles (2 kilometers), while S/2010 J 1 is about 1.8 miles (3 km) wide, researchers said. Enter a Crossword Clue Sort by Length The only other moon in the Solar System exhibiting water vapor plumes is Enceladus. [36] Like its fellow Galilean satellites, Europa is tidally locked to Jupiter, with one hemisphere of Europa constantly facing Jupiter. It has been theorized that these ions are responsible for the plasma within Jupiter's magnetosphere. Europa may have an ocean below the ice. The surface of Ganymede shares many similarities with Europa. Undoubtedly, there may be other solutions for Smallest of Jupiter's Galilean moons. Originally founded in 1999, Space.com is, and always has been, the passion of writers and editors who are space fans and also trained journalists. The first closeup photos were of low resolution compared to later missions. Rank the Galilean moons of Jupiter in order of amount of geological activity, from greatest to least. [42], It is estimated that Europa has an outer layer of water around 100km (62mi) thick--a part frozen as its crust and a part as a liquid ocean underneath the ice. [121] The surface-bounded atmosphere forms through radiolysis, the dissociation of molecules through radiation. It was referred to as "Jupiter I", or "The first satellite of Jupiter" until the mid-20th century. [44] Europa probably contains a metallic iron core. Scientists group the smaller, irregular satellites of giant planets such as Jupiter and Saturn in families with similar orbits and colors. The answer we have below for Smallest of Jupiters four Galilean moons has a total of 6 letters. Callisto has an ancient, heavily cratered and unaltered ice surface and the way it rotates indicates that its density is equally distributed, suggesting that it has no rocky or metallic core but consists of a homogeneous mix of rock and ice. It is the 4th largest moon in the solar system. [4][35], Europa orbits Jupiter in just over three and a half days, with an orbital radius of about 670,900km. They also reveal significant alteration of the surface. The larger bands are more than 20km (12mi) across, often with dark, diffuse outer edges, regular striations, and a central band of lighter material. In 2023, NASAs Volatiles Investigating Polar Exploration Rover (VIPER) will land near the western edge of the Nobile Crater at the Moons South Pole. Finding plumes at Europa is an exciting prospect, but scientists warn itll be tricky, even from up close. The first letter of the answer is: E E 2. The Galilean moons of Jupiter are four moons that orbit Jupiter. Close-up photos of the surface of Europa support the idea of a liquid ocean beneath the surface. [20] The estimated eruption rate at Europa is about 7000kg/s[110] compared to about 200kg/s for the plumes of Enceladus. [156] Japan proposed Jupiter Magnetospheric Orbiter. [57], Europa's most striking surface features are a series of dark streaks crisscrossing the entire globe, called lineae (English: lines). Studies have also concluded that Europa's ocean would have been rather acidic at first, with large concentrations of sulfate, calcium, and carbon dioxide. Europa's tilt could influence calculations of how much of its history is recorded in its frozen shell, how much heat is generated by tides in its ocean, and even how long the ocean has been liquid. Io is the innermost Galilean moon. Europa was courted by Zeus and became the queen of Crete. [38] Thus, the tidal flexing kneads Europa's interior and gives it a source of heat, possibly allowing its ocean to stay liquid while driving subsurface geological processes. [15], Land mapping surveys had the same problem determining longitude, though with less severe observational conditions. [50] Investigation revealed that Callisto may possibly have a subsurface ocean of liquid water at depths less than 300 kilometres. [25][26] NASA's Europa Clipper is expected to be launched in October 2024,[27][28] with a complementary lander possible based on its findings. By Daisy Dobrijevic last updated 8 June 2023 The Jovian system is teeming with moons, big and small. Galileo's discovery had practical applications. The level of Ganymede's tidal heating could not provide enough heat to make an ocean of liquid water. These various families are believed to have formed when comets or asteroids smashed into larger moons long ago. Volcanic water eruptions splitting the surface of Europa, and even geysers have also been considered as a cause. Europa: The second innermost Galilean moon is Europa, which takes its name from the mythical Phoenician noblewoman who was courted by Zeus and became the queen of Crete. Europa, along with Jupiter's three other large moons, Io, Ganymede, and Callisto, was discovered by Galileo Galilei on 8 January 1610,[1] and possibly independently by Simon Marius. [36], The prominent markings that criss-cross the moon seem to be mainly albedo features, which emphasize low topography. [6] In his dedicatory introduction, Galileo wrote: Scarcely have the immortal graces of your soul begun to shine forth on earth than bright stars offer themselves in the heavens which, like tongues, will speak of and celebrate your most excellent virtues for all time. The surface is a mix of two types of terrainhighly cratered dark regions and younger, but still ancient, regions with a large array of grooves and ridges. The two Voyager probes traveled through the Jovian system in 1979, providing more-detailed images of Europa's icy surface. Jupiter's regular satellites are believed to have formed from a circumplanetary disk, a ring of accreting gas and solid debris analogous to a protoplanetary disk. [138] Because it is deeply embedded within Jupiter's magnetosphere, Europa receives about 5.40 Sv of radiation per day. [6] On February 13, 1610, Galileo wrote to the Grand Duke's secretary: "God graced me with being able, through such a singular sign, to reveal to my Lord my devotion and the desire I have that his glorious name live as equal among the stars, and since it is up to me, the first discoverer, to name these new planets, I wish, in imitation of the great sages who placed the most excellent heroes of that age among the stars, to inscribe these with the name of the Most Serene Grand Duke."[6]. Named after Galileo Galilei, who observed them in either December 1609 or January 1610, and recognized them as satellites of Jupiter in March 1610,[2] remaining the only known moons of Jupiter until the discovery of the fifth largest moon of Jupiter Amalthea in 1892. Visible with common binoculars . This generates so-called Rossby waves that travel quite slowly, at just a few kilometers per day, but can generate significant kinetic energy. Ganymede, Callisto, Io, Europa Rank the Galilean moons by their orbital period, from longest to shortest. Europas torus ionizes through the process of neutral particles exchanging electrons with its charged particles. [19] These moons are, in increasing order of distance from Jupiter: Io (Jupiter I) is the innermost of the four Galilean moons of Jupiter; with a diameter of 3642kilometers, it is the fourth-largest moon in the Solar System, and is only marginally larger than Earth's moon. [88][89][90], The presence of sodium chloride in the internal ocean has been suggested by a 450nm absorption feature, characteristic of irradiated NaCl crystals, that has been spotted in HST observations of the chaos regions, presumed to be areas of recent subsurface upwelling. The rotation of the three inner moons, in contrast, indicates differentiation of their interiors with denser matter at the core and lighter matter above. Other models suggest that Galilean satellites formed in a proto-satellite disk, in which formation timescales were comparable to or shorter than orbital migration timescales. Galileo imaging team members argue for the existence of a subsurface ocean from analysis of Voyager and Galileo images. [92], Ocean tides are converted to heat by frictional losses in the oceans and their interaction with the solid bottom and with the top ice crust. Visible with common binoculars, the invention of the telescope enabled the discovery of the moons in 1610. [160], Europa Orbiter Its objective would be to characterize the extent of the ocean and its relation to the deeper interior. [142] In response, NASA commissioned Europa lander concept studies in 2011, along with concepts for a Europa flyby (Europa Clipper), and a Europa orbiter. All of the newly discovered moons are small and far out, taking more than 250 days to orbit Jupiter . [66], An alternative hypothesis suggests that lenticulae are actually small areas of chaos and that the claimed pits, spots and domes are artefacts resulting from over-interpretation of early, low-resolution Galileo images. [179] Some scientists have speculated that life on Earth could have been blasted into space by asteroid collisions and arrived on the moons of Jupiter in a process called lithopanspermia.[180]. The other 91 known moons and the rings together make up just 0.003% of the total orbiting mass. Today's crossword puzzle clue is a general knowledge one: Smallest of Jupiter's Galilean moons. It was last seen in British general knowledge crossword. [19] In addition, the Hubble Space Telescope detected water vapor plumes similar to those observed on Saturn's moon Enceladus, which are thought to be caused by erupting cryogeysers. The new study, which details the discovery and tracking of S/2010 J 1 and S/2010 J 2, will appear this summer in The Astronomical Journal. The reason for this is that the direction of the spin pole may change by as much as a few degrees per day, completing one precession period over several months. [20] The current Galilean moons were still affected, falling into and being partially protected by an orbital resonance which still exists for Io, Europa, and Ganymede. . [19] Europa is thought to contain 8% ice and water by mass with the remainder rock. S/2010 J 2 takes 1.69 years to zip around Jupiter, and its average distance is 13.06 million miles (21.01 million km). There are few craters on Europa, because its surface is tectonically too active and therefore young. NASA scientists are calling for a framework that provides context for findings related to the search for life. We have 1 possible answer in our database. 890 subscribers in the Jupiter community. That discovery changed the way we see the universe. It was last seen in British general knowledge crossword. Europa's prime meridian is a line passing through this point. This top-down diagram shows the orbits of moons around Jupiter: Purple denotes the Galilean moons, yellow for Themisto, blue for the Himalia group, cyan and green for Carpo and Valetudo, respectively, and red for far-out retrograde moons. We will try to find the right answer to this particular crossword clue. Clay-like minerals (specifically, phyllosilicates), often associated with organic matter on Earth, have been detected on the icy crust of Europa. It is one of the most heavily cratered satellites in the Solar System, and one major feature is a basin around 3000km wide called Valhalla. The smallest moon is Deimos, at Mars, only seven miles in diameter, although its size now is rivaled by the small shepherd moons discovered by Cassini at Saturn and by others yet to be counted and named in the rings around Jupiter, Saturn and other giant gas planets in the outer Solar System. [51][52] Europa's icy crust has an albedo (light reflectivity) of 0.64, one of the highest of all moons. [16] The predominant model suggests that heat from tidal flexing causes the ocean to remain liquid and drives ice movement similar to plate tectonics, absorbing chemicals from the surface into the ocean below. Enter a Crossword Clue Sort by Length Europa /jrop/ (listen), or Jupiter II, is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet of all the 95 known moons of Jupiter. All this evidence suggests that the nearer a moon is to Jupiter the hotter its interior. [80] The existence of the induced moment requires a layer of a highly electrically conductive material in Europa's interior. Molecular oxygen is the densest component of the atmosphere because it has a long lifetime; after returning to the surface, it does not stick (freeze) like a water or hydrogen peroxide molecule but rather desorbs from the surface and starts another ballistic arc. [21], The tidal forces are about 1,000 times stronger than the Moon's effect on Earth. The European Space Agency's Jupiter Icy Moon Explorer (JUICE) is a mission to Ganymede launched on April 14, 2023 that will include two flybys of Europa. When there is too much stress, it cracks. The main difficulty in observing the moons from Earth is their proximity to Jupiter, since they are obscured by its brightness. [17][38] The ultimate source of this energy is Jupiter's rotation, which is tapped by Io through the tides it raises on Jupiter and is transferred to Europa and Ganymede by the orbital resonance. Future US, Inc. Full 7th Floor, 130 West 42nd Street, The Voyager probes discovered three more inner satellites in 1979, so Europa is now counted as Jupiter's sixth satellite, though it is still referred to as Jupiter II. It is one of the largest and most heavily cratered satellites in the solar system. This "neutral cloud" has been detected by both the Cassini and Galileo spacecraft, and has a greater content (number of atoms and molecules) than the neutral cloud surrounding Jupiter's inner moon Io. [14] Galileo used this system in his notebooks but never actually published it. [17]:1516, The main problem with the Jovian moon technique was that it was difficult to observe the Galilean moons through a telescope on a moving ship, a problem that Galileo tried to solve with the invention of the celatone. This interpretation is controversial. [76] This leads to a volume of Europa's oceans of 31018m3, between two or three times the volume of Earth's oceans. [133] Europa's subsurface ocean is thought to be subsequently warm however. Each generation of moons to have formed would have spiraled into Jupiter and been destroyed, due to tidal interactions with Jupiter's proto-satellite disk, with new moons forming from the remaining debris. Advertisement Coins. Undoubtedly, there may be other solutions for Smallest of the four Galilean moons of Jupiter, thought to contain a vast ocean. [34] Heat energy from tidal flexing ensures that the ocean remains liquid and drives geological activity. The volcanic eruptions are so frequent and cover the surface so thoroughly that any clear evidence of tectonic activity is likely to be buried. It was referred as the first satellite of Jupiter. Ganymede has a high number of craters, but many are gone or barely visible due to its icy crust forming over them. [111][112], In May 2018, astronomers provided supporting evidence of water plume activity on Europa, based on an updated critical analysis of data obtained from the Galileo space probe, which orbited Jupiter between 1995 and 2003. [12] The first hints of a subsurface ocean came from theoretical considerations of tidal heating (a consequence of Europa's slightly eccentric orbit and orbital resonance with the other Galilean moons).