The groups of Jupiter’s moons
Jupiter’s moons are often split into three specific groups:
Inner moons
These are the moons which orbit closest to Jupiter and they are sometimes known as the Amalthea group. The names of the inner moons of Jupiter are Metis, Adrastea, Amalthea, and Thebe.
Galilean moons
The largest four moons of Jupiter – Io, Europa, Ganymede and Callisto – were discovered by Galileo in 1610 and are known as the Galilean moons. They each have a radii larger than any of the dwarf planets and they are some of the largest objects in the solar system outside of the eight planets by mass. Ganymede is actually larger than Mercury in diameter.
Outer moons
The other moons are known as irregular satellites because of their eccentric and distant orbit paths. They are the furthest from Jupiter and are substantially smaller objects. Many of these moons are captured asteroids pulled in by the gravitational forces of Jupiter.
Facts about the inner moons of Jupiter
Metis
Discovered by Stephen Synnott through images taken by the Voyager 1 in 1979, Metis is the closest moon to Jupiter. It has a diameter of 40 km (25 miles) and orbits Jupiter in 0.294780 Earth days, which is faster than Jupiter rotates on its axis.
It is named after the Greek Titaness Metis, who was the first wife of the god of the skies, Zeus. It is thought that Metis is an asteroid that was captured by Jupiter’s gravity. The moon orbits at 128,000 km (79,500 miles) from Jupiter and has a mass of 9 x 1016kg.
Adrastea
The second closest moon to Jupiter is Adrastea which has a diameter of 20 km (12 miles)12 miles (20 km) and orbits 129,000 km (80,000 miles) from Jupiter. It was discovered in 1979 by David Jewitt using the Voyager 2 and is named for the Greek goddess Adrasteia, who passed out rewards and punishments.
Adrastea has a mass of 1.91 x 1016kg and like Metis it orbits Jupiter faster than it takes for Jupiter to rotate on its axis – in 0.29826 Earth days.
Amalthea
Amalthea is the third moon from Jupiter and is the reddest object in the solar system. It was discovered by Edward Emerson Barnard in 1892. Amalthea is not a spherical moon with a diameter of 232 x 146 x 134 km (145 x 91 x 83 miles). It orbits 181,300 km (112,700 miles) from Jupiter, located in the faint Gossamer ring.
The moon is named for Amalthea in Greek mythology, who was the foster-mother of Zeus and nursed the god of the skies when he was a baby with goats milk. It is the largest of the inner moons of Jupiter and is most likely an asteroid captured by Jupiter. It takes Amalthea 0.49817905 Earth days to orbit Jupiter and like all the inner moons, it is tidally locked to the planet – the same side of the moon always faces Jupiter. Amalthea also gives off more heat than it receives from the Sun.
Thebe
The fourth moon from Jupiter is Thebe. It has a diameter of 110 x 90 km (68 x 56 miles) and orbits 222,000 km (138,000 miles) from Jupiter. Thebe was discovered by Stephen P. Synnott in 1979 and officially named in 1983.
In Greek mythology, Thebe was a nymph and the daughter of the river god Asopus. It is likely that Thebe, along with Amalthea, provide the dust for the Gossamer ring where they are located. Thebe has a mass of 8 x 1017kg and it takes the moon 0.6745 day Earth days to orbit Jupiter.
Facts about the Galilean moons of Jupiter
Io
Io is a large, rocky and volcanically active moon which is very vivid with bright colors due to the molten sulfur that they volcanoes spit out. These violent conditions mean that it is not the kind of world which would be able to sustain human life. In fact, Io lies in the doughnut-shaped plasma cloud around Jupiter, known as the “Io plasma torus” which is the result of Jupiter’s very strong magnetic field.
As Io rotates, this torus strips ions from Io as it rotates, effectively making it an electrical reactor. The result is a level of radiation on Io that is 1000x stronger than the level needed to kill a human being.
With a diameter of 3,636 km (1,942 miles), Io is very close in size to our Moon and it is around 422,000 km (220,000 miles) from Jupiter. Io has a mass of 8.93×1022 kg and takes 1.77 Earth days to orbit Jupiter.
More facts about Io
Europa
Europa is a large, dense and icy moon of Jupiter with a very smooth surface – it is the smoothest object in our solar system. The surface of Europa is covered with long, crisscrossing trackway but it has few craters. Around 3.8 to 4.1 billion years ago, many objects in the solar system were bombarded with asteroids and comets – a period known as the Late Heavy Bombardment Period. Since Europa is so smooth, it is believed that the moon, like Earth, has been able to recover its surface.
One scientific theory is that Europa contains a large liquid water ocean heated by its corde beneath the frozen icy shell – making it a world that may be able to sustain human life.
Europa has a diameter less than 3,138 km (2,000 miles) making it smaller than the Earth’s moon. Europa orbits Jupiter in 3.55 days, sits at a mean distance of 670,900 km (420,000 miles) from Jupiter and has a mass of 4.80×1022 kg.
More facts about Europa
Ganymede
The largest moon of Jupiter is Ganymede – a large, icy moon with a diameter of around 5,268 km (3,400 miles) that is scarred with craters. It is larger in diameter than the planet Mercury and the dwarf planet Pluto. In fact, Ganymede is the largest moon in the solar system.
Named for the handsome Trojan boy that Zeus took away to be the cup bearer for the gods, Ganymede has a magnetic field and is believed to have a molten iron core. It takes the moon 7.15 earth days to orbit Jupiter. Ganymede’s mass is 1.48×1023 kg and it orbits Jupiter at a distance of around 1,070,000 km (664,000 miles).
More facts about Ganymede
Callisto
Callisto is the eighth moon of Jupiter and is a large, dark but low-density moon which is covered with impact craters. It is home to the Valhalla crater, which is nearly 4,000 km in diameter and the largest crater in the solar system. It is the outermost of the Galilean moons, orbiting 1,883,000 km (1,170,000 miles) from Jupiter.
It takes Callisto 16.7 days to complete its orbit around Jupiter and during that time it will have travelled more than seven million miles. Callisto has about 99% the diameter of the planet Mercury, but has only 1/3 the mass at 1.08×1023 kg.
More facts about Callisto
Facts about the outer moons of Jupiter
Leda
Leda is the ninth moon from Jupiter and is also the smallest moon with a mean diameter of 16 km (9.9 miles). Charles Kowal discovered Leda in 1974. It is named for the queen of Sparta and the mother of Pollux and Helen of Troy – the father was Zeus. The moon has a mass of 5.68 x 1015kg. It takes 238.72 Earth days for Leda to orbit Jupiter and it orbits at a distance of 11,094,000 km (6,900,000 miles) from the planet.
Himalia
Jupiter’s tenth moon is Himalia, discovered by Charles Perrine in 1904. Himalia is 170 km (110 miles) in diameter and orbits 11,480,000 km (7,000,000 miles) from Jupiter. The moon is named after a nymph who produced three sons with Zeus (Jupiter). It has a mass of 9.5 x 1018kg and takes 250.5662 days to orbit Jupiter.
Lysithea
The eleventh moon from Jupiter’s surface is Lysithea, a world which is 24 km (15 miles) in diameter and orbits at around 11,720,000 km (7,200,000 miles) from Jupiter. It has a mass of 8 x 1016kg and takes 259.22 Earth days to orbit Jupiter. Lysithea is named after the daughter of Oceanus in Greek mythology. Lysithea was discovered in 1938 by Seth Nicholson.
Elara
Elara was discovered in 1905 by Charles Perinne and is Jupiter’s twelfth moon. It has a diameter of 80 km (50 miles) and orbits Jupiter at a distance of 11,737,000 km (7,250,000 miles. Elara has a mass of 8 x 1017kg and takes 259.6528 Earth days to orbit Jupiter. It is named after Elara from Greek mythology, the mother of the giant Tityus, fathered by Zeus.
Ananke
Ananke, Jupiter’s thirteenth moon, was discovered in 1951 by Seth Nicholson. Ananke has a diameter of 20 km (12.5 miles) and orbits 21,200,000 km (13,100,000 miles) from Jupiter. The moon has a mass of 4 x 1016kg and it take Ananke 631 Earth days to orbit Jupiter. The moon is also in a retrograde orbit – which means it orbits in the opposite direction of Jupiter. It is named after Ananke, the mother of Adrastea by Zeus, in Greek mythology.
Carme
Discovered in 1938 by Charles Nicholson, Carme is the fourteenth moon of Jupiter. It has a diameter of 30 km (18.5 miles) and orbits at a distance of 22,600,000 km (13,800,000 miles) from Jupiter. Carme has a mass of 9 x 1016kg and orbits Jupiter in 692 Earth days. It is in a retrograde orbit which moves in the opposite direction of Jupiter. In Greek mythology Carme was the mother of Britomartis, a Cretan goddess, fathered by Zeus.
Pasiphae
Pasiphae is the fifteenth moon of Jupiter and was discovered by P. Melotte in 1908. It orbits Jupiter at a distance of 23,500,000 km (14,600,000 miles) and has a diameter of 36 km (22 miles). Its mass is 2 x 1023kg and it takes Pasiphae 735 Earth days to orbit Jupiter in a retrograde orbit path. In Greek mythology, Pasiphae was the wife of Minos and mother of the Minotaur.
Sinope
Jupiter’s sixteenth moon is Sinope, discovered in 1914 by Seth Nicholson. Sinope has a diameter of 28 km (17.5 miles) and it orbits Jupiter at a distance of 23,700,000 km (14,700,000 miles). It has a mass of 8 x 1016kg and it orbits Jupiter in a retrograde orbit that takes 758 Earth days. In Greek mythology, Sinope was a woman who was courted unsuccessfully by Zeus, and she remained a virgin for her entire life.
Callirrhoe
Jupiter’s seventeenth confirmed moon was Callirrhoe, also known as S/1999 J 1, and was discovered by Tim Spahr on July 18, 2000. It has a diameter of 8.6 km (5.3 miles) and orbits Jupiter at a distance of 24,100,000 km (14,975,000 miles). Callirrhoe has a mass of 9 × 1014kg and orbits Jupiter in a retrograde orbit that takes 758.77 Earth days to complete. In Greek mythology, Callirrhoe was the daughter of the river god Achelous, one of Zeus’ (Jupiter’s) many conquests.
FAQs
Jupiter's Moons · Facts about the Moons of Jupiter? ›
Jupiter's four largest moons were the first moons discovered beyond Earth. They are called the
From top to bottom, the moons are Io, Europa, Ganymede and Callisto.
What are the 4 special moons of Jupiter? ›The Moons of Jupiter
The four largest — Io, Europa, Ganymede and Callisto — were discovered by Galileo in 1610 and are known as the Galilean Satellites.
Once this gas and dust had condensed to form Jupiter, the leftover material coalesced and grew over time to form the Galilean moons. This makes Jupiter's largest moons likely as old of the rest of the Solar System: about 4.5 billion years old.
What are the 5 major moons of Jupiter? ›Himalia was discovered in 1904, Elara in 1905, Pasiphae in 1908, Sinope in 1914, Lysithea and Carme in 1938, Ananke in 1951, and Leda in 1974.
What is Jupiter's 2nd largest moon? ›Callisto is Jupiter's second largest moon after Ganymede and it's the third largest moon in our solar system.
What is the largest moon? ›Ganymede has a radius of 1,635 miles (2,631 kilometers) and is the largest moon in our solar system. It's bigger than Mercury and Pluto. Ganymede is about 665,000 miles (1.07 million kilometers) from Jupiter, which orbits about 484 million miles (778 million kilometers) from the Sun.
What is Jupiter ice moon called? ›Europa's surface is made of water ice and so it reflects 5.5 times the sunlight than our Moon does. Europa orbits Jupiter at about 417,000 miles (671,000 kilometers) from the planet, which itself orbits the Sun at a distance of roughly 500 million miles (780 million kilometers), or 5.2 astronomical units (AU).
What are Jupiter's most important moons? ›Ganymede. Ganymede is the largest satellite in our solar system. It is larger than Mercury and Pluto, and three-quarters the size of Mars. Harpalyke was discovered Nov.
What is the smallest moon of Jupiter? ›Overview. With a mean radius of 6.2 miles (10 kilometers), assuming an albedo of 0.04, Leda is the smallest moon in the Himalia group, a family of Jovian satellites which have similar orbits and appearance, and are therefore thought to have a common origin.
What is Jupiter's old name? ›
The British had a tendency to Anglicize most of the words they found and changed Jove (the Roman name for Zeus) to their version called Jupiter.
Does one of Jupiter's moons have life? ›"We don't expect life on the surface of these moons and it's not feasible yet to go down [underneath the ice crust] to where there might be life."
What are Jupiter's moons named after? ›They are called the Galilean satellites after Italian astronomer Galileo Galilei, who first observed them in 1610. The German astronomer Simon Marius claimed to have seen the moons around the same time, but he did not publish his observations and so Galileo is credited with their discovery.
What are the 7 largest moons? ›The seven large moons are, in decreasing order of size: Ganymede, Titan, Callisto, Io, our moon, Europa, and Triton. Ganymede, Callisto, Io, and Europa are the four Galilean moons that Galileo saw in 1610. Titan is the large moon of Saturn, and Triton is the large moon of Neptune.
What planet has 7 moons? ›saturn: 7 moons work together to keep Saturn's largest ring in place - The Economic Times.
Which planet has 9 moons? ›Uranus was the last giant planet without any known irregular moons, but since 1997 nine distant irregular moons have been identified using ground-based telescopes.
What moon is Titan? ›Saturn's largest moon, Titan, is an icy world whose surface is completely obscured by a golden hazy atmosphere. Titan is the second largest moon in our solar system. Only Jupiter's moon Ganymede is larger, by just 2 percent. Titan is bigger than Earth's moon, and larger than even the planet Mercury.
What is Jupiter's prettiest moon? ›Europa – Jupiter's Moon
Europa is perhaps the most promising place to look for present-day environments suitable for life. Europa is thought to have an ocean of salty water below its frozen outer shell of ice.
Jupiter's menagerie of moons includes the largest in the solar system (Ganymede), an ocean moon (Europa) and a volcanic moon (Io). Many of Jupiter's outer moons have highly elliptical orbits and orbit backwards (opposite to the spin of the planet).
What is 400 times larger than the Moon? ›The sun and the moon are about the same size when you look at them in the sky, though that's just thanks to the coincidence that the sun is about 400 times farther away than the moon and also about 400 times bigger. Another fun coincidence is that the radius of the sun is about twice the distance to the moon.
What is the smallest moon? ›
If we thought Phobos was a small moon, Deimos is even smaller. In fact, Deimos is the smallest known moon in the Solar System measuring only 9 miles across. Deimos is approximately 23,460 km from Mars, which is much further out than Marss other moon, Phobos.
What is the lava moon of Jupiter? ›Jupiter's rocky moon Io is the most volcanically active world in the solar system, with hundreds of volcanoes, some erupting lava fountains dozens of miles (or kilometers) high.
What is the fiery moon of Jupiter? ›Io is the closest of Jupiter's larger moons and the most volcanic world in our solar system, with over 300 active volcanoes, thanks to its proximity to the huge gravitational pull of Jupiter.
Which moon has water ice? ›Saturn's moon Enceladus is a small, icy body, but Cassini revealed this ocean world to be one of the solar system's most scientifically interesting destinations.
What is Jupiter's most unique moon? ›Ganymede. Ganymede is the solar system's largest moon and the only natural satellite with its own magnetic field. Because of its magnetic field, Ganymede has its own northern lights around the regions near its north and south poles.
Which of Jupiter's moons can support life? ›Three of Jupiter's moons – Europa, Ganymede and Callisto – are home to large, underground oceans of liquid water that could support life.
What is the new moon of Jupiter? ›Meet Jupiter's new moons
Jupiter's new moons are not as large and flashy as the Galilean moons Io, Europa, Ganymede, and Callisto. They are instead members of the planet's irregular satellites — comparatively small outer moons with distant, atypical orbits. Some are no wider than a kilometer.
Close-up of Dark Side of Jupiter Moon Ganymede
This image of the dark side of Ganymede was taken by NASA's Juno spacecraft during its June 7, 2021, flyby of the icy moon.
A: The outer atmosphere of Jupiter is mostly hydrogen and helium, with some water droplets, ice crystals, and ammonia crystals. When these elements form clouds, they create shades of white, orange, brown, and red, the colors of Jupiter.
Who is Jupiter's daughter? ›VENUS. VENUS, the daughter of Jupiter and Dione, was at first the goddess of gardens (Met XIV. 585-595).
Who is Jupiter's son? ›
| Jupiter | |
|---|---|
| Children | Mars, Minerva, Vulcan, Bellona, Juventas, Hercules |
| Equivalents | |
| Greek equivalent | Zeus |
| Norse equivalent | Thor |
Jupiter was particularly promiscuous, a fact that made for much strife between him and his wife Juno, the goddess of marriage.
How many of Jupiter's moons have water? ›The latest study suggests that the presence of water on Jupiter's Moon Europa makes it habitable. Jupiter has four Galilean moons - Io, Europa, Ganymede, and Callisto. And in a surprising development, NASA's scientists have found water on the surface of one of the smallest of the four Galilean moons orbiting Jupiter.
Can we land on Jupiter's moons? ›The transportation of humans to Europa would be one of the primary challenges to colonization. Since Jupiter is on average 630.4 million kilometers away from Earth at a given time, it would take at least 3 years just to get into Europa's orbit plus additional time to land.
Are Jupiter's moons in its rings? ›Jupiter's rings
The two small moons Adrastea and Metis orbit here within the main ring and are thought to be the source of dust of this ring. Gossamer rings — These are very faint and wide composed of microscopic debris from the moons Amalthea and Thebe.
The surface of Ganymede, the largest moon in the solar system, is composed of half water ice and half rock. This satellite of Jupiter is unique for its long, curved grooves in the crust, that make it unlike any other planetary body ever seen.
What moons are named after gods? ›The moons of Mars (Phobos and Deimos) were named by Asaph Hall in 1878, soon after he discovered them. They are named after the sons of the god Ares (the Greek equivalent of the Roman god Mars).
Can I name a Jupiter moon? › What planet has 100 moons? ›Saturn officially has the most moons of any planet in the solar system, usurping Jupiter. The International Astronomical Union (IAU) has announced the addition of 28 natural satellites for the ringed planet, bringing its total to 117 versus Jupiter's 95.
Who has 67 moons? ›Jupiter has 67 known moons — the most of any planet in the solar system — and more are expected to be discovered by the Juno spacecraft. There are three main moon groups, the first being the four primary Jovian satellites. They were discovered by Galileo on Jan. 7, 1610, with his low-powered telescope.
What moon hit Saturn? ›
Chrysalis Lost
However, sometime between 200 and 100 million years ago, Chrysalis became destabilized and eventually drifted so close to Saturn it disintegrated. While much of the material from the moon descended into the planet, a small fraction flung outwards to circle the planet and became the rings we know today.
So how did these researchers come to their conclusion of 600 moons for Jupiter? Schematic representation of the orbits of Jupiter's 79 known moons. The 45 new tiny moons potentially discovered are thought to have irregular orbits and belong to the retrograde group.
Which planet has 9 rings? ›Saturn is the sixth planet from the sun. This close-up view of Saturn's rings shows that many tiny rings make up the larger rings around the planet.
What planet has 200 moons? ›Due to its immense size, mass, and gravitational pull, Jupiter has the most satellites of any planet in the Solar System. At present, the Jovian system includes 80 known moons, though it is estimated that it may have over 200 moons and moonlets (the majority of which are yet to be confirmed and classified).
What has 79 moons? ›The planet Jupiter now has a total of 79 identified moons. More than 400 years after Galileo Galilei discovered the first of Jupiter's moons, astronomers have found a dozen more — including one they've dubbed "oddball" — orbiting the planet.
Which planet has 82 moons? ›If all of these moons get confirmed, Saturn will have 82 moons. And that's not counting Saturn's beautiful rings. Saturn's moons have great names like Mimas, Enceladus, and Tethys. One of these moons, named Titan, even has its own atmosphere, which is very unusual for a moon.
Who has 82 moons? ›Saturn has a whopping 82 moons ranging in size. While Titan is larger than the planet Mercury, some of the moons are as small as a sports arena.
What are the 3 rings of Jupiter? ›| Name | Radius (km) | Notes |
|---|---|---|
| Halo ring | 92,000–122,500 | |
| Main ring | 122,500–129,000 | Bounded by Adrastea |
| Amalthea gossamer ring | 129,000–182,000 | Connected with Amalthea |
| Thebe gossamer ring | 129,000–226,000 | Connected with Thebe. There is an extension beyond the orbit of Thebe. |
According to this definition, in 2023, the full Moons of July, August, and September all qualify as supermoons—reaching 90% of perigee, the Moon's closest approach to Earth.
What is so special about Jupiter's 3 Galilean moons? ›Jupiter's 4 largest moons exhibit some of the most interesting geology in the solar system. They were discovered by Galileo Galilei and are known as the Galilean moons. Jupiter's largest moon, Ganymede, is larger than Mercury while the other three are larger than Pluto.
What planet has 3 big moons? ›
A single crescent moon is a familiar sight in Earth's sky, but with Saturn's many moons, you can see three or even more. The three moons shown here -- Titan (3,200 miles or 5,150 kilometers across), Mimas (246 miles or 396 kilometers across), and Rhea (949 miles or 1,527 kilometers across) -- show marked contrasts.
Does Jupiter have 7 rings? ›Jupiter has only a couple of well defined rings with faint 'gossamer' rings surrounding them.
What are the 4 rings of Jupiter called? ›Jupiter is known to have 4 sets of rings: the halo ring, the main ring, the Amalthea gossamer ring, and the Thebe gossamer ring.
How old are the rings of Jupiter? ›Composition and origin: The rings are mostly dust and small, dark particles kicked up by meteorite impacts on the planet's small ring moons. Ring material must be continually replenished after it is destroyed by Jupiter's radiation or gets pushed into the planet, giving the rings an age of less than 1 million years.
What is a pink moon? ›The pink moon is a nod to the bountiful blooming flowers and trees that the spring weather brings. In particular, the pink moon gets its name from a hot pink wildflower, Phlox subulata, that grows in a thick mat of vibrant foliage, commonly referred to as creeping phlox, moss phlox or moss pink.
How rare is blue moon? ›How often does a blue moon happen? Normally blue moons come only about every two or three years.
What is a purple moon? ›A purple moon is the special name given to the second full moon of a 30-day month, especially in April. Generally, second full moon in a month is called the blue moon.
What is the coolest moon on Jupiter? ›Ganymede. Ganymede is the solar system's largest moon and the only natural satellite with its own magnetic field. Because of its magnetic field, Ganymede has its own northern lights around the regions near its north and south poles.
What is Jupiter's most important moon? ›Ganymede. Ganymede is the largest satellite in our solar system. It is larger than Mercury and Pluto, and three-quarters the size of Mars.
Which planet has 1,000 moons? ›Saturn officially has the most moons of any planet in the solar system, usurping Jupiter. The International Astronomical Union (IAU) has announced the addition of 28 natural satellites for the ringed planet, bringing its total to 117 versus Jupiter's 95.
What planet is blue and green? ›
Uranus gets its blue-green color from methane gas in the atmosphere. Sunlight passes through the atmosphere and is reflected back out by Uranus' cloud tops. Methane gas absorbs the red portion of the light, resulting in a blue-green color.