In one myth, he is abducted by Zeus in the form of an eagle, to serve as a cup-bearer in the home of the Greek gods. It is the most volcanically-active body in our solar system, and the only one other than Earth. As with other destinations in the Solar System where the radiation environment is high and the local gravity is a fraction of Earth's, the creation of long-term habitats will also enable medical research. The clouds make the planet look like it has stripes. How many moons does Jupiter have? ", "Those heading to Callisto are invited to take a tour of the Great Craters! Why does this planet have so many moons? That's a key observation for understanding the formation (and destruction) of moons. This moon is the subject of a significant amount of scientific research, as many astronomers believe that there may be water on Europa. Plus, Jupiter has some moons orbiting in the opposite direction to the others, and so also in the opposite direction to Jupiters rotation. This is similar to what happens on Earth, where geological activity causes hydrothermal vents to form on the ocean floor. With a diameter of about 3275 miles, Ganymede is the largest moon in the Solar System, even larger than the planet Mercury (though only half as massive), and is the only satellite known to have a magnetic field. The presence of this liquid water interior and geological activity is bolstered by evidence of cryovolcanic activity surface plumes. 26 of the moons are awaiting them. Welcome back to ourongoing "Interplanetary Series." For further details of our complaints policy and to make a complaint please click here. The four Jovian planets in the solar system are: As with many scientific words, there can be more than one meaning to the term Jovian Moons. Gift Article. With a diameter of around 3,000 miles, Callisto is the third largest satellite in the Solar System and about 99% the size of Mercury. Create your account. Ganymede is covered in dark regions with large numbers of craters, and lighter regions with unusual grooves. In 2022, Jupiter's opposition is September 26. Toes teaches us how many moons Jupiter has and how big they are. For many years, we knew of 16 moons for the largest planet in our solar system. Above this rocky interior is a layer of water ice that is estimated to be around 62 miles thick. Potential for Life Jupiter's environment is probably not conducive to life as we know it. Well that's quite the list of challenges and hazards, isn't it? Callisto also has no volcanoes or large mountains. Of the 79 moons that Jupiter has, only 8 are regular. succeed. The first four discovered Jovian satellites . Based on their spectroscopy, the majority of Jupiter's Trojans appear to be D-type asteroids, similar to what is found in the outer regions of the Main Asteroid Belt. This is why the precursor known is added to moon totals. Triton is Neptune's largest moon. Answer: Lately, this question has had a changing answer! These moons average five kilometres in diameter, and 17 of them orbit Saturn in the direction opposite to its rotation, and to the other moons. To inquire about a licence to reproduce material, visit our Syndication site. The astronomer, Galileo Galilei discovered them in 1610. 53 of the moons have names. Home Science There's something mysterious about Jupiter's many moons Meghan Bartels Jul 19, 2016, 11:58 AM Three of its largest moons cast shadows on Jupiter. If, say, something the size of Baby Yoda orbited Jupiter, All Rights Reserved. The most compelling evidence for the existence of a liquid, iron-nickel-rich core is Ganymedes intrinsic magnetic field. Jupiter has 79 moons, 53 of which have been named and 26 which have no name. Jupiter is a gas giant, meaning that it is comprised primarily of helium and hydrogen, rather than solid particles, like rock. However, NASA estimates that such a propulsion system could reduce transit times between Earth and Mars to 100 days. In addition, she was the spotlight educator for National Geographic in late 2019. The planet can support so many moons because its size and mass give it gravitational stability. Callisto is the furthest away of the Galilean moons, and is named after a female nature god in Greek mythology. The most obvious challenge when it comes to establishing human outposts in the Jovian system is the time it would take to make even a one-way trip. The Galilean moons are still the largest, and probablythe coolest, of Jupiter's moons. Scientists have known about Amalthea for a long time as Edward Emerson Barnard discovered it in 1892. We remind you once again that the export of flora and fauna is strictly forbidden and punishable by law. Others were found much earlier, such as Pasiphae in 1908 and Lysethea in 1938. Jupiter has 79 known moons. Over time, Jupiter and Earth vary considerably in their distance from each other, going from 365 million milesapart at their closest to 601 million miles at their farthest. This means asteroids near Jupiter are either pulled in and destroyed - or go into orbit. The irregular satellites are substantially smaller objects with more distant and eccentric orbits and are subdivided into those with prograde and retrograde orbits. He thought they were stars, but the next evening they had moved the wrong direction compared to the planet. The medical treatments derived from this could inform future missions to the edge of the Solar System and interstellar space. These tides are actually on the solid surface, and they grow to 300 feet in height. These asteroids are theorized to be composed of an outer layer of organic-rich silicates, anhydrous silicates, and carbon that surround a water ice interior. If you give an email address, you may receive an email notifying you when someone else has added a comment to the same page. Several retrograde satellites make up part of Jupiters outer moons. Scientists speculate that Callisto may have liquid water around 300 kilometers below its pockmarked surface, making it a possible candidate for life. While rotating space stations will be essential for combatting the effects of low gravity, residents could volunteer to live in low-g for years at a time as part of research experiments - similar to NASA's Twin Study. Several of them have not been completely named yet, as they were recently discovered by scientists. @media(min-width:0px){#div-gpt-ad-planetsforkids_org-box-3-0-asloaded{max-width:320px!important;max-height:50px!important;}}if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[320,50],'planetsforkids_org-box-3','ezslot_1',197,'0','0'])};__ez_fad_position('div-gpt-ad-planetsforkids_org-box-3-0');@media(min-width:0px){#div-gpt-ad-planetsforkids_org-box-3-0_1-asloaded{max-width:320px!important;max-height:50px!important;}}if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[320,50],'planetsforkids_org-box-3','ezslot_2',197,'0','1'])};__ez_fad_position('div-gpt-ad-planetsforkids_org-box-3-0_1'); .box-3-multi-197{border:none !important;display:block !important;float:none !important;line-height:0px;margin-bottom:5px !important;margin-left:auto !important;margin-right:auto !important;margin-top:5px !important;max-width:100% !important;min-height:50px;padding:0;text-align:center !important;}. Jupiter has 79 moons and is known as the 'king of the planets'. Bottom line: You can see Jupiter's moons - Io, Europa, Ganymede and Callisto, known as the Galilean satellites - with . Plus, get practice tests, quizzes, and personalized coaching to help you It has very few impact marks from craters hitting it, and it has an unusually high orbit. 53 have been confirmed and 26 (79 total) provisional moons awaiting confirmation of discovery. With everything from habitats and fuel depots present on (and in orbit around) the Galilean moons, missions destined to and from the outer Solar System would have a base to stop, take on supplies, rest, and refuel. These moons average five kilometres in diameter, and 17 of them orbit Saturn in the direction opposite to its rotation, and to the other moons. These irregular satellites are split up into two distinct categories: prograde satellites and retrograde satellites. 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. For instance, getting to and from the Jovian system will require more advanced propulsion and life support systems. Saturn's moon Enceladus has enticed scientists for years with its plumes fizzing their way up from an ocean beneath a thick crust of ice. Jupiter currently has 79 known moons, with a dozen having been discovered in 2018. With a diameter of about 1,940 milesand a mass of10.58 1022 lbs, Europa is slightly smaller than Earths Moon and 65% as massive. Amalthea is the fifth largest moon, and Thebe is the seventh largest moon of all the Jupiter moons. All told, there are 80 satellites in orbit of Jupiter, which are divided between the regular and irregular groups. This artistic rendering of Saturn highlights its rings. Copyright 2019 Planet For Kids. Neptune's largest moon is Triton. NASA, ESA, A. Simon (Goddard Space Flight Center),. lessons in math, English, science, history, and more. This means asteroids near Jupiter are either pulled in and destroyed - or go into orbit. It is a bit smaller our own Moon, but it is thought to contain twice as much water as Earth. Comments may be merged or altered slightly such as if an email address is given in the main body of the comment. Io, Europa, and Ganymede all experience tidal flexing in their interior, a process that leads to hydrothermal activity at the core-mantle boundary. AdrasteaAitneAmaltheaAnankeAoedeArcheAutonoeCallirrhoeCallistoCarmeCarpoChaldeneCylleneDiaEireneElaraErinomeErsaEuantheEukeladeEuphemeEuporieEuropaEurydomeGanymedeHarpalykeHegemoneHelikeHermippeHerseHimaliaIoIocasteIsonoeJupiter LIJupiter LIIKaleKallichoreKalykeKoreLedaLysetheaMegaclyteMetisMnemeOrthosiePandiaPasiphaePasitheePhilophrosynePraxidikeS/2003 J10 12 16 18 19 2 4 23 9S/2011 J1 and 2S/2016 J1 and 2 (Valetudo)S/2017 J1 2 3 5 6 7 8 9SinopeSpondeTaygeteThebeThelxinoeThemistoThyone, News Group Newspapers Limited in England No. Now there's a new element to the story . In all cases, it is theorized that tidal flexing leads to hydrothermal activity at the core-mantle boundary. Over time, plants and animals could be imported to create a self-sustaining ecosystem that would replenish the water and air and provide regular sources of food. Jupiter has a whopping 53 moons of its own, with 14 more waiting to be confirmed! The other Jovian planets are: Moon numbers are always qualified with the word known because moons are continually being discovered. For Jupiter, a single transit would take 1000 days (2.74 years), which is still a very long time for crews to remain in space (and that is just one way - they would still need to get home). The first conjunction (a celestial event in which two objects appear close together in Earth's night sky) of the moon and a planet will occur on July 7, when an 80%-lit waning gibbous moon will be . Smaller than our Moon, Europa has a diameter of 3,100 km / 1,900 mi, and its mostly made out of silicate rock, and it has a water-ice crust and probably an iron-nickel core. Then, zooming out from the planet, they've tracked the orbits of 56 of the smaller moons orbiting within a mind-boggling 15 million miles of Jupiter. Plants, animals, and humans in these settlements will need to undergo regular medical tests to determine the long-term effects of exposure to both. Only 53 of the moons are named. The creation of larger pinwheel stations throughout the Jovian system that would simulate 1 g would provide a long-term solution to the effects of low gravity. JUPITER is by far the biggest planet in our solar system. By subscribing, you agree to our Terms of Use and Policies You may unsubscribe at any time. In our previous installments, we looked at what it would take to live on Mercury, Venus, the Moon, Mars, and the Main Asteroid Belt. If you experience any symptoms of 'gravity sickness,' just use the Jovis app, which is free to download to your personal devices. Here's all you need to know. How many moons does Jupiter have? This means asteroids near Jupiter are either pulled in and destroyed - or go into orbit. (adsbygoogle = window.adsbygoogle || []).push({}); Copyright 2023, Pinoria.com. Lately, our largest neighbor has been picking up satellites so quickly that astronomers haven't even been sweating over giving them real names (hope S/2000 J11 rolls off your tongue!). However, one should not conclude that the presence of indigenous life means that no human habitats are possible. It is the only celestial body in Earth's solar system that has standing water on its surface besides Earth. Jupiter was the planet with the most moons until 2019, when 20 new moons were found in orbit around Saturn. In his book Entering Space, Robert Zubrin described how the outer Solar System might one day become the "Persian Gulf" of the Solar System. For further details of our complaints policy and to make a complaint please click this link: thesun.co.uk/editorial-complaints/, Jupiter has lots of moons because its huge gravitational force pulls them into its orbit, Close up of Jupiter taken by Nasa's Juno spacecraft, A view of Jupiter's moon Europa, created from images taken by NASA's Galileo spacecraft in the late 1990's, Independent Press Standards Organisation (IPSO). Of these 79 moons, 53 have names including Dia, Thebe and Kale, while the other 26 are yet to be named. These are the largest of all Jupiters moons. The planet with the largest number of moons is Saturn with 82 moons including unconfirmed moons. These moons may share a single origin. How many moons does Jupiter have? It is believed that water is a vital component for alien life, but the water that potentially lies on Europa is covered by a thick layer of ice. Also, while doses from Jupiter's belts would be negligible under normal circumstances, they would be much higher when the satellites occasionally pass through Jupiter's enormous magnetotail, which extends in the anti-sunward direction from Jupiter for hundreds of millions of kilometers. Size comparison between Earth and Jupiter is pictured in this section. published 14 May 2022 A round-up of information about Jupiter, the largest planet in the solar system. So far, 79 Jupiter moons have been found; astronomers may find more in the future. The planet can support so many moons because its size and mass give it gravitational. The observations helped overthrow the belief that the Earth was the center of the universe. An American non-profit organization built the first 3D-printed school in Madagascar, Nuclear Engine for Rocket Vehicle Application, National Council on Radiation Protection and Measurements, Revolutionary Concepts for Human Outer Planet Exploration. Another major hazard is the intense radiation the Galilean moons are exposed to. The nature of these Ocean Worlds also presents opportunities for innovative living solutions. The rest are labeled with their discovery year. Its surface is almost all water and ice, and it is thought to be the most likely planet other than Earth for life to exist. These include the Carme group, the Ananke group, and the Pasiphae group. Some of Jupiters moons are tiny, around 2km in diameter, such as Pandea, Dia, and Ersa. Scientists now think Jupiter has 79 moons. The planet can support so many moons because its size and mass give it gravitational. Its surface is made of ice and shows few asteroid impacts. It is larger than the planet Mercury. Those aren't like our moon or other larger ones, which formed by clumps of matter sticking together. NASA, ESA, Hubble Heritage Team When. With a diameter of about 3275 miles, To ensure their health and safety, NASA has established an upper limit of 50 mSv/year (50 rem/year). Ganymede is one of the Galilean satellites - the four largest moons of Jupiter - which were discovered by Galileo. First you see the four innermost small moons, then the Galilean moons. Titan, along with Triton, both have atmospheres of their own. A planet this has many moons, given the size and gravitational pull. Sign up for notifications from Insider! Moons are still being discovered as astronomical equipment becomes more precise. Spectra obtained from the surface indicates that it consists of small, bright patches of pure water ice, intermixed with patches of a rockice mixture, and extended dark areas made of a non-ice material. Europa is significantly less dense than any of the other Galilean Moons, which indicates that its composition is similar to most moons in the outer Solar System - i.e., differentiated between a rock interior composed of silicate rock and a possible iron core. It has a total of 79 Moons, some have names, others awaiting names so at the moment just have designations. C-type asteroids are the most common type in the Solar System and are composed of hydrogen, helium, hydrated minerals,and other volatiles. These moons are much smaller than the Galilean moons and are closer to Jupiter. If there is life within Europa's interior oceans, any intrusions by human or robotic missions could contaminate the Europan biosphere and cause a complete collapse. It is also the only known moon that has its own magnetic field. They were the first to be found and are also the most scientifically interesting. However, platforms built in orbit around the planet could facilitate operations where hardened robotic spacecraft ("skydivers" perhaps?) In the exact opposite situation of Triton, Miranda is the innermost moon of Uranus. The Latest 40-Year Study Finds Mysterious Patterns in Temperatures at Jupiter Scientists have discovered 26 more. Both Ganymede and Calisto are icy moons thought to have water under the icy crust. During these windows, a one-way mission will still take six to nine months to get there. Io is one of the most geologically active objects in the Solar System, with over 400 active volcanoes and more than 100 mountains (some taller than Mount Everest), and lava plumes that have been seen reaching up to 300 miles into space. Jupiter has 79 known moons, several of which were discovered relatively recently. This same strategy could be used for Europa, but in far stricter ways. It has one of the most unique compositions in the solar system that is completely nonhomogeneous. Depending on the location, habitats could be built within surface craters or within the ice sheets. It has a total of 79 Moons, some have names, others awaiting names so at the moment . Until then, they are temporarily named with a series of numbers, symbols, and letters. Moon Formation Theories & Overview | What is the Capture Theory? The four moons discovered by Galileo are called the Galilean moons. Motion of the Moon: Sidereal Month vs. Synodic Month. As they drift through Jupiter's magnetic field, they would extract energy that could be beamed to habitats using microwave lasers. Jovian Planets Characteristics & List | What are Jovian Planets? These could be used to create everything from oxygen and drinking water to fertilizers and propellants. Complete name list of all of Jupiter's Moons. This is similar to proposals for long-term human habitation and terraforming on Mars. It evenhas some astronomers thinking they could be close to solving the mystery of how all these moons came to be. Called the Amalthea group after the largest satellite, Amalthea, these moons have nearly circular orbits and provide the dust that maintains Jupiters rings. Ever since the Voyager 1 and 2 probes passed through the Jovian system in 1979, scientists have speculated that Europa may have an ocean beneath its icy surface. copyright 2003-2023 Study.com. These include NASA's Europa Clipper mission and the ESA's Jupiter Icy Explorer (JUICE) missions, which will arrive around Jupiter in the 2030s. These aurorae are brightest near Io's equator due to the lack of an intrinsic magnetic field, which causes electrons traveling from Jupiter to impact its atmosphere directly. With the right technology and a lot of effort, it may even be possible to establish settlements on Jupiter's moons. To see all content on The Sun, please use the Site Map. Alexandrea has taught secondary science for over six years. The regular group is subdivided into the inner satellites (aka. For astronauts and settlers, long-term exposure to this radiation could lead to serious health problems. This consists of magnesium and iron-bearing hydrated silicates, carbon dioxide, sulfur dioxide, possibly ammonia, and various organic compounds. It is riddled with asteroid strikes, including the 3000 meter Valhalla crater, the largest in the solar system. Compared to the other Galileans, Callistos surface is saturated by ancient craters, with newer ones formed over older ones. A report by the non-profit Lifeboat Foundation indicated that the Jovian moons are preferable destinations beyond the Moon and Mars because their surface gravity is comparable to the Moon (0.165 g). Also known as the "Galileans" or "Jovian Moons," these satellites have long been a source of fascination for astronomers and scientists. We know those first four moons now asthe Galilean moons, although Galileo actually called them the Medicean Stars to suck up to his patrons, the famous Medici family. But in all cases, they will need to provide protection against the elements and have all the necessary amenities so people feel connected to the surface. The Fact a Day: Did you know thatJupiter 79 moons! Based on multiple observations, the surface pressure of the Galilean Moons' atmospheres is estimated to be less than one nano pascal (Pa) - one-trillionth of Earth's atmospheric pressure (101,325 Pa). Although it is large, being almost the size of the planet Mercury, it is made up of ice and rock. Some day, interplanetary tourists could be listening to messages like this: "Welcome to the Jovian System! But with the right technology and strategies, humans could actually make a life for themselves in the Jovian system. Ganymede is not only Jupiter's largest moon but the largest moon in the solar system. Saturn, 82 known moons. Plus, Jupiter has some moons orbiting in the opposite direction to the others, and so also in the opposite direction to Jupiters rotation. The city lights are beautiful. Long-term exposure to low gravity is likely to lead to muscle atrophy, bone density loss, diminished organ function, and psychological and cognitive issues as well. On this moon, habitats will have to take advantage of the surface ice for protection. The unmanned Galileo spacecraft was sent to study Jupiter and its moons in 1989, by NASA. There are 79 confirmed moons around Jupiter. Once again, Zubrin acknowledged this challenge in his book, Entering Space: "For while the ballistic interplanetary trajectories are made possible by chemical or nuclear thermal propulsion are adequate for human exploration of the inner Solar System and unmanned probes beyond, something a lot faster is going to be needed to sustain interplanetary commerce encompassing the gas giants.". That discovery changed the way we see the universe. But due to its mixed composition, it has less than one-third the mass of Mercury. Uranus does have a small rocky core that is surrounded by frozen gases, like helium, hydrogen, and a small amount of methane. Here's all you need to know. Astronomers thought it might have been destroyed. JUPITER is by far the biggest planet in our solar system. A LOT! At the end of the day, establishing a human presence in space comes down to strategies that allow us to live sustainably away from Earth. As we say in the Jovis tongue: Wit el amor hamaaree de guia, shsh ji possible*. Earth is smaller than Jupiter's Big Red Dot or Great Red Spot, also pictured, which is a hurricane that has been swirling on the planet for centuries. Jupiter, the largest planet in our solar system, is well-known for its captivating moons. The planet can support so many moons because its size and mass give it gravitational stability. But that number began to explode in 2000, thanks to an astronomer named Scott Sheppard, who went looking for "irregular satellites." Stay up to date with what you want to know. What kind of challenges would humans face to live on Jupiter's icy moons and what discoveries would await? Unfortunately, none of these atmospheres are dense enough to retain heat or be breathable by Earth lifeforms. It took a decade to rediscover the little rock, but it's now firmly back on the books. By: Mark Mancini | Updated: Feb 15, 2023 Four of the many moons orbiting Jupiter are shown. Jupiter has 79 moons, 53 of which have been named and 26 which have no name. For example, it has grooved terrain that is attributed to cryovolcanism and tidal flexing that heated the interior and strained the surface ice, leading to cracks, graben, and faults that led to its brighter and darker surface patches. "The Sun", "Sun", "Sun Online" are registered trademarks or trade names of News Group Newspapers Limited. Located within the ice sheet, these stations offer viewing opportunities forEuropan sharks, rays, and other indigenous lifeforms. Upon arrival, it could be repurposed as a space station (temporary or permanent) that settlers could use to get a little "gravity therapy.". The moon Europa is one of the brightest in our solar system. Our journalists strive for accuracy but on occasion we make mistakes. Origin and evolution The relative masses of the Jovian moons. Models of Ios interior indicate that it is differentiated between a silicate-rich crust and mantle, a molten interior, and a solid core made rich in iron or iron-sulfide. Callisto is the most heavily cratered object in our solar system. Nuclear-Thermal Propulsion (NTP) is another concept that NASA is considering for the sake of deep-space missions. They are named: Ganymede is the largest moon that orbits Jupiter. Similar considerations have been made for Ganymede and Callisto, though Europa appears to be the most likely candidate. Ganymede is not only the largest of Jupiters moons, but it is also the largest moon in the solar system. Saturn Saturn has 145 moons that we know of so far. All these moons have eccentric orbits, and all appear to be irregular in shape. Image via EarthSky. Not all The Moons orbit in the same direction, some orbit prograde and other retrograde. Try refreshing the page, or contact customer support. The prominent markings crisscrossing Europa (called lineae) are another major feature. The gas giant has a large following worthy of its gargantuan mass. How many moons does Jupiter have? Another method would be to place satellites with powerful electromagnets in space. Prograde means that they rotate the same direction as Jupiter. Unlike Jupiter's many other satellites, these were the only four massive enough to achieve hydrostatic equilibrium (become spherical). Asteroids that share Jupiter's orbit are known as Trojans, which are differentiated between the "Greek" camp (those in the Sun-Jupiter L4 point and named for Greek heroes of the Trojan War) and the "Trojan" camp (those in the trailing L5 point and named for Trojan heroes). This could also facilitate the construction of fuel depots in the Jovian system that would be used by spacecraft coming to and from the outer Solar System. They are largely composed of ice, volatiles, silicate minerals, and metals - differentiated between a crust, a liquid mantle, and a core of rock and metal. For Europa, scientists have long suspected that the combination of interior oceans, hydrothermal activity, and ocean floor niches could allow for life. It is the most volcanically-active body in our solar system, and the only one other than Earth. This atmosphere is the product of radiolysis, where UV radiation from the Sun and charged particles from Jupiter's magnetosphere cause ice to sublimate and become chemically disassociated with hydrogen and oxygen gas. Saturn is the planet with the most moons in our solar system - it has 82 compared to Jupiters 79. A name is preferred even if it's a random made up one by yourself. Jupiter Moons Overview In Depth list view grid view Adrastea Aitne Amalthea Ananke Aoede Arche Autonoe Callirrhoe Callisto Carme Carpo Chaldene Cyllene Dia Eirene Elara Erinome Ersa Euanthe Eukelade Eupheme Euporie Europa Eurydome Ganymede Harpalyke Hegemone Helike Hermippe Herse Himalia Io Iocaste Isonoe Jupiter LII | S/2010 J2 Saturn is the planet with the most moons in our solar system - it has 82 compared to Jupiters 79. To see all content on The Sun, please use the Site Map. Although Ganymede is as big as Mercury, it is only half the density. The "traditional" moon count most people are familiar with stands at 290: One moon for Earth; two for Mars; 95 at Jupiter; 146 at Saturn; 27 at Uranus; 14 at Neptune; and five for dwarf planet Pluto.According to NASA/JPL's Solar System Dynamics team, astronomers have documented more than 460 natural satellites orbiting smaller objects, such as . Also, learn about some of the Jovian moons orbiting Saturn, Neptune, and Uranus. We hope that you enjoyed your time aboardDyauspitar Station and have fully adapted to the local gravity. It has been six weeks since Juice began its journey, and in that time . Jupiter has a long history of surprising scientists - all the way back to 1610 when Galileo Galilei found the first moons beyond Earth. Ganymede is the seventh closest moon to Jupiter, and it is the largest ofthe moons. for astronauts operating aboard the International Space Station (ISS) and other missions in Low Earth Orbit (LEO). Saturn is the planet with the most moons in our solar system - it has 82 compared to Jupiters 79. Jupiter also has the biggest moon in our solar system, Ganymede.