The science
Our Solar System contains a huge number of different cosmic bodies, including 200 large satellites orbiting the main planets, dwarf planets and even asteroids. Many of these satellites have interesting features. In this article you can get acquainted with the 10 most interesting satellites of our star system and learn about their features.
1) Nereid, satellite of Neptune
Nereid was discovered in 1949 Gerard Kuiper. It is Neptune's third largest moon. It has the most eccentric orbit of all the satellites in the solar system. Because of this, the distance between the planet and its satellite varies greatly. The closest the satellite can get to Neptune is 1.4 million kilometers. The farthest it can go is 9.6 million kilometers. To make one revolution around Neptune, given such a far distance from it, Nereid requires 360 Earth days.
2) Mimas, satellite of Saturn
This one is not large satellite was opened in 1789 William Herschel. The average diameter of this object is about 400 kilometers. Mimas is notable for the fact that on its surface there is a giant crater Herschel with a diameter of about 130 kilometers and a depth of 10 kilometers. Herschel is not the largest crater of the solar system's satellites, but it is very unusual. The crater covers one third of Mimas's surface and makes it look like the Death Star station from Star Wars.
3) Iapetus, satellite of Saturn
Discovered in 1671 Giovanni Cassini, Saturn's moon Iapetus has been recognized as one of the strangest moons in the solar system. The diameter of Iapetus averages 1,460 kilometers. Distinctive feature of this satellite is that it has sections different color that reflect light differently. One half of the planet is pitch black, while the other half is exceptionally light and bright. Because of this, we can only observe the satellite when it appears on one side of the planet. Iapetus also has a mountain range - an equatorial mountain ring, which reaches a height of about 10 kilometers and encircles the object along its equator. Scientists have put forward 2 hypotheses to explain the appearance of these mountains. According to one version, the ring formed at the beginning of the satellite’s existence, when Iapetus rotated much faster than it does now. Other scientists believe that the mountain range was formed from material from another satellite, which belonged to Iapetus itself, but crashed, and its debris settled on Iapetus' equator.
4) Dactyl, satellite of the asteroid Ida
Discovered in 1995 using spaceship Galileo, the satellite of the asteroid Ida - Dactyl - has about a kilometer in diameter. This satellite is notable because it was the first satellite discovered to orbit an asteroid. Scientists cannot yet say for sure about the origin of this satellite and do not know whether it is part of its native asteroid, or was once captured by this asteroid. Dactyl proves the existence of satellites on asteroids. After that, scientists noticed another two dozen similar satellites around various other asteroids in the Solar System.
5) Europa, satellite of Jupiter
Europa has been discovered Galileo Galilei in January 1610. It is quite a bit smaller than our Moon. Europa's surface is striking, carved with dark intersecting lines. Scientists suggest that the lines represent cracks and breaks in Europa's ice shell. Perhaps the cracks formed due to the influence of Jupiter and other satellites orbiting the planet. Beneath Europa's thick layer of ice there may be an ocean of liquid salt water that makes the moon special. Unlike Earth, it is believed that Europa has a very deep ocean, so it completely covers the entire satellite. Since Europa is located quite far from the Sun, its ocean froze, forming a crust about 100 kilometers thick. Perhaps due to internal more high temperature The water under the ice crust may remain liquid.
6) Enceladus, satellite of Saturn
Enceladus is the sixth largest moon of Saturn. It is not the largest, but has a number of interesting features. Enceladus was discovered in 1789 William Herschel. It is the brightest cosmic body in the solar system and reflects 100 percent of sunlight from its surface. This fact makes it one of the coldest places, the temperature on the surface of the satellite is about minus 200 degrees Celsius. As you can see in the image, this satellite has a number of impact craters, but there are also quite smooth areas that indicate that in the geologically recent past the surface of the satellite was leveled. On south pole The satellite has large dark faults, which also indicate recent geological activity. These fractures release tons of material that makes up Saturn's E ring.
7) Io, satellite of Jupiter
Io was discovered in January 1610 by the same Galileo Galilei. It is slightly larger than our Moon. Io is the most volcanically active place in the solar system. The satellite is covered with many volcanoes, which release jets of substances at a distance of about 300 kilometers above the surface. Normally, an object of this size should have ceased volcanic activity a very long time ago, but due to Io’s orbital resonances with Jupiter, Europa and Ganymede, tidal heating occurs in the bowels of the satellite. If we omit the details, we can say that the increased volcanic activity of the satellite is associated with nearby cosmic bodies and its composition internal characteristics. Tidal heating causes most of the material lying beneath the surface to remain in a liquid state, which constantly changes the surface of the satellite.
8) Titan, satellite of Saturn
Titan is the only satellite besides our Moon on whose surface a spacecraft has landed. It was opened in 1655 Christian Huygens. Titan is the second largest moon in the Solar System. It is covered in a dense, foggy atmosphere consisting mainly of methane, nitrogen and ethane. This satellite is known for having an atmosphere similar to that of a planet. This is also the only place in the solar system where, as scientists have proven, there is liquid on the surface, although this liquid is far from water, but methane.
9) Triton, satellite of Neptune
Triton was discovered in October 1846 by astronomer William Lassell, 17 days after the discovery of Neptune itself. This is the largest of the satellites of the planet Neptune. Triton has the distinction of being the only large moon in the solar system that orbits a planet in the opposite direction to the planet's rotation. This suggests that Triton is a captured satellite of Neptune, because all natural satellites in the solar system rotate in the same direction as their planets. The only thing is that scientists cannot yet come to a consensus on how Neptune captured such a large body into its orbit. Triton is one of the coldest places in the solar system. When Voyager 2 flew past it in 1989, he found that Triton's temperature remained minus 235 degrees Celsius, that is, it was close to absolute zero. Voyager 2 also helped discover active geysers on Triton, so Triton is considered one of the few geologically active moons in the Solar System.
10) Ganymede, satellite of Jupiter
Discovered in 1610 Galileo Galilei, Ganymede is the largest moon in the solar system. It is larger than the planet Mercury and is also about three times the size of Mars. It is so large that it would be considered a planet if it orbited the Sun rather than Jupiter. A notable feature of this satellite is that it is the only satellite in our system that has its own magnetic field. It has a molten iron core, which creates a magnetic field. In 1996, the space telescope Hubble discovered thin layer oxygen around the moon, but it is so thin that it cannot support life.
Some of these moons still remain a mystery to astronomers, because not everywhere has a human foot set foot before, but somewhere the existence of living organisms is quite possible! But what we do know for sure is at least their size. This list will introduce you to the 10 largest planetary moons in our solar system.
10. Oberon, satellite of Uranus (average diameter - 1523 kilometers)
Oberon, also known as Uranus IV, is the most distant satellite from the center of Uranus, the second largest among the other satellites of this planet and the ninth largest among all known satellites of ours. solar system. Discovered in 1787 by explorer William Herschel, Oberon is named after the mythical king of elves and fairies mentioned in Shakespeare's A Midsummer Night's Dream. Oberon's orbit lies partially outside the magnetosphere of Uranus.
9. Rhea, satellite of Saturn (average diameter - 1529 kilometers)
Rhea is the second largest satellite of Saturn and the ninth largest satellite in the entire Solar System. At the same time, it is the second smallest cosmic body in our solar system, second only to the asteroid and the dwarf planet Ceres in this rating. Rhea received this status for confirmed data that she has hydrostatic equilibrium. Discovered in 1672 by Giovanni Cassini.
8. Titania, satellite of Uranus (average diameter - 1578 kilometers)
It is the largest moon of Uranus and the eighth largest in the solar system. Discovered in 1787 by William Herschel, Titania was named after the fairy goddess from Shakespeare's A Midsummer Night's Dream. Titania's orbit does not extend beyond the magnetosphere of Uranus.
7. Triton, satellite of Neptune (average diameter - 2707 kilometers)
Triton is the largest satellite of the planet Neptune, discovered on October 10, 1846 by the English astronomer William Lassell. In our solar system, it is the only large moon with a retrograde orbit. Triton moves in the opposite direction to the rotation of its planet. With its 2,707 kilometers in diameter, Triton is considered the seventh largest moon in the solar system. There was a time when Triton was considered a dwarf planet from the Kuiper belt due to its retrograde and compositional properties similar to Pluto.
6. Europa, a satellite of Jupiter (average diameter - 3122 kilometers)
It is the smallest of the Galilean moons orbiting Jupiter and the sixth closest to its planet. It is also the sixth largest satellite in the Solar System. Galileo Galilei discovered Europa in 1610 and named this celestial body after the legendary mother of the Cretan King Minos and lover of Zeus.
5. Moon, satellite of the Earth (average diameter - 3475 kilometers)
It is believed that our Moon formed 4.5 billion years ago, shortly after the formation of the Earth itself. There are several hypotheses about its origin. The most common among them says that the Moon was formed from fragments after the collision of the Earth with the cosmic body Theia, comparable in size to Mars.
4. Io, a satellite of Jupiter (average diameter - 3643 kilometers)
Io is the most geologically active celestial object in our solar system, earning that title with at least 400 active volcanoes. The reason for this extreme activity is the heating of the satellite's interior due to tidal friction caused by the gravitational influence of Jupiter and the other Galilean moons (Europa, Ganymede and Callisto).
3. Callisto, a satellite of Jupiter (average diameter - 4821 kilometers)
Galileo Galilei discovered Callisto, as well as several other moons of Jupiter, in 1610. Possessing impressive dimensions, this satellite makes up 99% of the diameter of Mercury, but only a third of its mass. Callisto is the fourth Galilean satellite of Jupiter in terms of distance from the center of the planet, with an orbital radius of 1,883,000 kilometers.
2. Titan, satellite of Saturn (average diameter - 5150 kilometers)
This is the sixth ellipsoidal satellite of Saturn. Very often it is called a planet-like satellite, because the diameter of Titan is 50% larger than the diameter of our Moon. In addition, it is 80% heavier than our Earth's satellite.
1. Ganymede, a satellite of Jupiter (average diameter - 5262 kilometers)
Ganymede is composed equally of silicate rocks and frozen water. It is a fully differentiated celestial body, rich in iron, with a liquid core and an outer ocean that may contain more water than the sum of all of the Earth's oceans. The surface of Ganymede has two types of relief. The dark regions of the satellite are littered with craters from asteroid impacts that supposedly occurred 4 billion years ago. This landform covers approximately a third of the satellite.
Just the other day my mother told me: she comes into the room in the evening, sees me (I was only five or six years old) looking outside the window and crying. When asked what upset me, I answered: “I feel sorry for the Moon, the Earth only has one.” The next day, mom opened the book to a page about the planet, which there were satellites more than everyone else- so as not to reassure my daughter later.
Planet with the most moons
If we talk about the solar system, the undisputed leader here is Jupiter. Him as many as 69 satellites- those who are definitely not lonely without company. Moreover, these are only those that we managed to find - it is assumed that in practice theirabout a hundred.
It was thanks to them that Jupiter acquired its unusual striped color.
Galilean satellites
The very first moons of Jupiter were discovered by Galileo. Of course, his telescope was not very powerful, which is why he saw only four the biggest Jovian moons:
I came up with names for them Simon Mari. His first records were actually dated earlier than Galileo, but the scientist made a fatal mistake - he delayed the publication. Mari tried for a very long time to prove that it was he who discovered satellites first. He failed, but as a consolation prize he received opportunity to name them as he pleases.
And I chose names from mythology for the name - in honor of the beloved of the god Jupiter. The idea was not bad, but even the loving god clearly did not have so many loving affections.
Jupiter - the thief of satellites
Some of Jupiter's moons rotate in the opposite direction. It is believed that they were ordinary cosmic bodies, moving on their own and not touching anyone, but unfortunately they got into the gravitational field of a gas giant - and now they have to spin around it.
But since you’re going to revolve around the invader, you have to do it in defiance of everyone. This movement is called retrograde. They are quite easy to recognize by their names. The rule is: if the name ends with the letter “e”, then the satellite is moving in the opposite direction.
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Since childhood, I loved astronomy, which is why I studied this science well. My favorite planet was Jupiter. Jupiter -largest planet Solar system, this gas giant is the fifth in distance from the Sun, and has a large number of satellites.
Jupiter has the largest number of satellites
Since ancient times, Jupiter was known to our ancestors; they composed many legends about this planet and called it by the names of their deities. The modern name of the planet is named after the Roman deity - thunderer Jupiter. On Earth, Jupiter can be seen with the naked eye. and it's not strange, because The planet is second only to the Sun in mass. Some scientists believe that if Jupiter were a little larger, it would turn into another Sun in our system. Since the planet does not have a solid surface and liquid water, it is believed that life on it is impossible, but scientists suggest the existence of life in upper layers its atmosphere.
Large moons of Jupiter
Jupiter Andhas at least sixty seven satellites, but perhaps there are many more of them, the number of satellites may exceed a hundred. It is ironic that the satellites were given the names of deities somehow related to the divine Jupiter. The most famous moons of Jupiter:
- Europa is a satellite of Jupiter, whichhas an ocean and where there is the presence of water, the presence of life is not excluded. Also, in the waters of the ocean of Europe there is a huge amount of oxygen, and this, in turn, makes it possible for the emergence of not only single-celled, but also more complex shapes life;
- And about - volcanic planet, which is covered with great volcanoes and the products of their eruptions;
- Ganymede -largest satellite in the entire solar system. Covered with deep craters, which indicate frequent meteor showers;
- Callisto- a planet that also has ocean water, like on Europa, life may exist on Callisto.
These four satellites synchronously rotate around Jupiter and always face one side towards it.
Small satellites of Jupiter
The remaining satellites are often irregularly shaped and represent rocky bodies. One of the most interesting small satellites - Amalthea. Amalthea was once a whole body, but due to meteorite bombardment, it broke up into parts, which were united under the influence of gravity, but never became a single whole.
It is assumed that the giant Jupiter once had many more satellites, but due to the planet's strong gravity, they fell to its surface.
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During my school years I really loved astronomy. Observations of stars, observation diaries - there was a special romance in this, which not everyone understands. The telescope was a cherished dream for me. And when they gave it to me, first I began to look at the planets. And my first object was not Saturn, with its rings. It was Jupiter, because of the galaxy of satellites.
How many moons does Jupiter have?
At the moment, 79 satellites are known: from dwarfs with a diameter of several kilometers to almost full-fledged planets. In addition, Jupiter has its own ring system. In addition, the number 79 is most likely not final. New satellites are still being discovered today, the last one became known this year, 2018.
It is simply impossible to list all these objects; most of them have alphanumeric names. But it’s worth mentioning the most basic ones, discovered by Galileo Galilei in 1610. These include:
- Europe;
- Ganymede;
- Calisto.
Their names were given by Simon Marius, another great scientist. They are taken from ancient Greek myths. These satellites can be considered the most unusual. Thus, Europe is completely covered with ice, under which there is an ocean. Scientists even admit the presence of life in it. And Io is the owner of the largest active volcano in the solar system.
Why does Jupiter have so many moons?
The number of Jupiter's satellites can be attributed to the fact that it is the largest object in our native solar system, after the Sun itself. Therefore, in the past, it easily captured small planets flying in similar orbits into its gravitational field. It also captured various dust, fragments, and asteroids, which served as the foundation for the formation of some satellites already in orbit around the giant.
How many satellites do other planets have?
Don't forget that other planets also have beads of objects orbiting around them. So, Saturn has 62 of them, Uranus has 27, Neptune has 14. Not far away is the dwarf Pluto, which has as many as five satellites.
So it turns out that our solar system is amazing and unique. Sometimes, to see miracles, all you have to do is look at the sky.
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In the summer of 2011, I excitedly watched the launch of the Juno interplanetary station to study Jupiter. It had to fly to the planet that had the most satellites in the solar system. The robot station did it. On solar powered she transmitted so much data that scientists will be busy deciphering them for several years.
How many moons does Jupiter have?
It is almost 2.5 times larger than all the planets in the solar system together. This huge mass, compared to the Sun, even shifts the center of gravity beyond its limits. Such colossal size and weight of the planet determine the huge number of satellites and the presence of dust rings.
In the 17th century, Galileo saw large satellites through a telescope:
- Europe;
- Ganymede;
- Callisto.
By the seventies of the 19th century, 9 more satellites were discovered.
Voyager 1, traveling to Saturn past Jupiter, recorded the presence of three new satellites in 1979. Later, 51 satellites were discovered thanks to new types of telescopes.
Jupiter is believed to have at least 100 “moons,” the study of which continues.
The largest
Io, the closest satellite to Jupiter, is affected by the gravitational forces of both the planet and Ganymede with Europa, which leads to heating of the body, deformation and active volcanic activity. Io's movement causes severe thunderstorms on Jupiter.
Europa is covered in water, in which life is believed to exist. The temperature on the surface is 150-220 degrees Celsius below zero - a “crystal” satellite with a metal core and a rocky mantle. There is oxygen in the atmosphere.
Ganymede is the largest moon in the Solar System. It is larger than Mercury. The surface is covered with ice and dotted with numerous craters, and oxygen is found in the atmosphere.
Callisto consists of water and stones and is the body with the most old surface. This is the site of a planned space base for Europa exploration.
Internal and external
In inner orbit to Io are:
- Metis;
- Amalthea;
- Adrastea;
- Thebe.
59 external satellites have been recorded. Those close to Jupiter rotate with it in the same direction, the rest - in the opposite direction.
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A satellite is a dense natural object that orbits a planet. Nothing specific scientific explanation does not provide a satisfactory answer to the question of how the satellites appeared, although several theories exist. The Moon was considered the only satellite, but after the invention of the telescope, satellites of others were discovered. Each planet has one or more satellites, except Mercury and Venus. Jupiter has the largest number of satellites - 67. Technological advances have allowed man to discover and even send spacecraft on expeditions to other planets and their satellites.
The largest moons in our solar system are:
Ganymede
Ganymede is the largest moon in our system, orbiting Jupiter. Its diameter is 5,262 km. The moon is larger than Mercury and Pluto, and could easily be called a planet if it were orbiting the Sun. Ganymede has its own magnetic field. Its discovery was made by the Italian astronomer Galileo Galilei on January 7, 1610. The satellite's orbit is about 1,070,400 km from Jupiter and it takes 7.1 Earth days to complete its orbit. The surface of Ganymede has two main types of landscapes. It has lighter and younger regions, as well as a darker crater area. The satellite's atmosphere is thin and contains oxygen in dispersed molecules. Ganymede is primarily composed of water ice and rock, and is believed to have underground oceans. The name of the satellite comes from the name of a prince in ancient Greek mythology.
Titanium
Titan is a satellite of Saturn with a diameter of 5,150 km, making it the second largest moon in the Solar System. It was discovered by the Dutch astronomer Christiaan Huygens in 1655. The satellite has a dense atmosphere similar to that of Earth. 90% of the atmosphere consists of nitrogen, and the remaining 10% consists of methane, small amounts of ammonia, argon and ethane. Titan makes a complete revolution around Saturn in 16 days. On the surface of the satellite there are seas and lakes filled with liquid hydrocarbons. This is the only cosmic body in the solar system, besides the Earth, that has water bodies. The name of the satellite is taken from ancient Greek mythology, in honor of the ancient gods called the Titans. Ice and rock make up the bulk of Titan's mass.
Callisto
Callisto is the second largest moon of Jupiter and the third largest large satellites Solar system. It has a diameter of 4821 km and is estimated by scientists to be about 4.5 billion years old; its surface is mostly dotted with craters. Callisto was discovered by Galileo Galilei on January 7, 1610. The satellite received its name in honor of a nymph from ancient Greek mythology. Callisto orbits Jupiter at a distance of about 1,882,700 km, and completes its orbit in 16.7 Earth days. It is the most distant moon from Jupiter, meaning it was not significantly exposed to the planet's powerful magnetosphere. Water ice, as well as other materials such as magnesium and hydrated silicates, make up most of the moon's mass. Callisto has a dark surface and is thought to have a salt sea underneath.
And about
Io is the third largest moon of Jupiter and the fourth in the Solar System. Its diameter is 3,643 km. The satellite was first discovered by Galileo Galilei in 1610. This is the most volcanically active cosmic body along with the Earth. Its surface mainly consists of floodplains of liquid rocks and lava lakes. Io is located approximately 422,000 km from Jupiter, and orbits the planet in 1.77 Earth days. The satellite has a spotted appearance with dominance of white, red, yellow, black and orange flowers. Io's atmosphere is dominated by sulfur dioxide. The moon was named after a nymph from ancient Greek mythology who was seduced by Zeus. Beneath Io's surface is an iron core and an outer layer of silicates.
Other large satellites
Other large satellites of the Solar System include: the Moon (3,475 km), Earth; Europa (3,122 km), Jupiter; Triton (2,707 km), Neptune; Titania (1,578 km), Uranus; Rhea (1,529 km), Saturn and Oberon (1,523 km), Uranus. Most observations of these satellites are made from Earth. Advances in technology make it possible for scientists to send spacecraft to different parts of the solar system to obtain more information about the planets and their satellites.
Table: TOP 10 largest satellites in the solar system
| Place in the ranking | Satellite, Planet | Average diameter |
| 1 | Ganymede, Jupiter | 5,262 km |
| 2 | Titan, Saturn | 5,150 km |
| 3 | Callisto, Jupiter | 4,821 km |
| 4 | Io, Jupiter | 3,643 km |
| 5 | Moon, Earth | 3,475 km |
| 6 | Europa, Jupiter | 3,122 km |
| 7 | Triton, Neptune | 2,707 km |
| 8 | Titania, Uranus | 1,578 km |
| 9 | Rhea, Saturn | 1,529 km |
| 10 | Oberon, Uranus | 1,523 km |
