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. In this list you will get acquainted with the 10 largest planetary satellites 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 Dream of summer night" 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 an asteroid and dwarf planet Ceres. 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)
This largest moon 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. This is the only one in our solar system big moon with a retrograde orbit. Triton is moving in the direction reverse rotation of your 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, and has earned this title for at least 400 years. 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 in equally consists 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 throughout the entire Earth in the sum of all its 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.
An Earth satellite is any object that moves along a curved path around a planet. The Moon is the original, natural satellite of the Earth, and there are many artificial satellites, usually in close orbit to the Earth. The path followed by a satellite is an orbit, which sometimes takes the shape of a circle.
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To understand why satellites move the way they do, we have to go back to our friend Newton. exists between any two objects in the Universe. If not for this force, a satellite moving near the planet would continue to move at the same speed and in the same direction - in a straight line. However, this rectilinear inertial path of the satellite is balanced by a strong gravitational attraction, directed towards the center of the planet.
Orbits of artificial earth satellites
Sometimes the orbit artificial satellite The Earth appears as an ellipse, a squashed circle that moves around two points known as foci. The same basic laws of motion apply, except that the planet is at one of the foci. As a result, the net force applied to the satellite is not uniform throughout the orbit, and the satellite's speed is constantly changing. It moves fastest when it is closest to Earth - a point known as perigee - and slowest when it is furthest from Earth - a point known as apogee.
There are many different satellite orbits of the Earth. Those who receive greatest attention- These are geostationary orbits because they are stationary over a certain point on the Earth.
The orbit chosen for an artificial satellite depends on its application. For example, live broadcast television uses the geostationary orbit. Many communications satellites also use geostationary orbit. Other satellite systems, such as satellite phones, can use low-Earth orbits.
Likewise, satellite systems used for navigation, such as Navstar or Global Positioning (GPS), occupy a relatively low Earth orbit. There are also many other types of satellites. From weather satellites to research satellites. Each of them will have their own own type orbit depending on its application.
The actual Earth satellite orbit chosen will depend on factors including its function, and the area in which it is to serve. In some cases, the Earth satellite's orbit can be as large as 100 miles (160 km) for a LEO low earth orbit, while others can reach over 22,000 miles (36,000 km) as in the case of a GEO low earth orbit.
The first artificial earth satellite
The first artificial earth satellite was launched on October 4, 1957 Soviet Union and was the first artificial satellite in history.
Sputnik 1 was the first of several satellites launched by the Soviet Union in the Sputnik program, most of which were successful. Satellite 2 followed the second satellite in orbit and also the first to carry an animal on board, a female dog named Laika. Sputnik 3 suffered the first failure.
The first earth satellite had an approximate mass of 83 kg, had two radio transmitters (20.007 and 40.002 MHz) and orbited the Earth at a distance of 938 km from its apogee and 214 km at its perigee. Analysis of radio signals was used to obtain information about the concentration of electrons in the ionosphere. Temperature and pressure were encoded over the duration of the radio signals it emitted, indicating that the satellite was not perforated by a meteorite.
The first earth satellite was an aluminum sphere with a diameter of 58 cm, having four long and thin antennas ranging from 2.4 to 2.9 m in length. The antennas looked like long mustaches. The spacecraft received information about the density upper layers atmosphere and radio wave propagation in the ionosphere. Instruments and sources electrical energy were placed in a capsule that also included radio transmitters operating at 20.007 and 40.002 MHz (about 15 and 7.5 m wavelength), the emissions were made in alternate groups of 0.3 s duration. Ground telemetry included temperature data inside and on the surface of the sphere.
Because the sphere was filled with pressurized nitrogen, Sputnik 1 had its first opportunity to detect meteorites, although it did not. The loss of pressure inside, due to penetration to the outer surface, was reflected in the temperature data.
Types of artificial satellites
There are artificial satellites different types, shapes, sizes and play different roles.
- Weather satellites help meteorologists predict the weather or see what's happening in this moment. A good example is the Geostationary Operational Environmental Satellite (GOES). These earth satellites typically contain cameras that can return photographs of Earth's weather, either from fixed geostationary positions or from polar orbits.
- Communications satellites allow the transmission of telephone and information conversations via satellite. Typical communications satellites include Telstar and Intelsat. Most important feature A communications satellite is a transponder—a radio receiver that picks up a conversation on one frequency, then amplifies it and retransmits it back to Earth on a different frequency. A satellite typically contains hundreds or thousands of transponders. Communications satellites are usually geosynchronous.
- Broadcast satellites transmit television signals from one point to another (similar to communication satellites).
- Scientific satellites, such as Space telescope Hubble, carry out all sorts of scientific missions. They look at everything from sunspots to gamma rays.
- Navigation satellites help ships and planes navigate. The most famous are the GPS NAVSTAR satellites.
- Rescue satellites respond to radio interference signals.
- Earth observation satellites checking the planet for changes in everything from temperature, forest cover, to ice cover. The most famous are the Landsat series.
- Military satellites The Earths are in orbit, but much of the actual position information remains secret. Satellites could include encrypted communications relay, nuclear monitoring, surveillance of enemy movements, early warning of missile launches, eavesdropping on terrestrial radio links, radar imaging, and photography (using essentially large telescopes that photograph militarily interesting areas).
Earth from an artificial satellite in real time
Images of the earth from an artificial satellite, broadcast in real time by NASA from the International space station. Images are captured by four cameras high resolution, isolated from low temperatures, allowing us to feel closer to space than ever before.
The experiment (HDEV) on board the ISS was activated on April 30, 2014. It is mounted on the external cargo mechanism of the European Space Agency's Columbus module. This experiment involves several high-definition video cameras that are enclosed in a housing.
Advice; put the player in HD and full screen. There are times when the screen will be black, this can be for two reasons: the station is passing through an orbital zone where it is at night, the orbit lasts approximately 90 minutes. Or the screen goes dark when the cameras change.
How many satellites are there in Earth orbit 2018?
According to the index of objects launched into outer space maintained by the United Nations Office for Space Affairs outer space(UNOOSA), there are currently about 4,256 satellites in Earth's orbit, up 4.39% from last year.
221 satellites were launched in 2015, the second most in a single year, although it is below the record number of 240 launched in 2014. The increase in the number of satellites orbiting the Earth is less than the number launched last year because satellites have a limited lifespan. Large communications satellites last 15 years or more, while small satellites such as CubeSats can only expect a service life of 3-6 months.
How many of these Earth orbiting satellites are operational?
The Union of Scientists (UCS) clarifies which of these orbital satellites work, and it's not as much as you think! There are currently only 1,419 operational Earth satellites—only about one-third of the total number in orbit. This means there is a lot of useless metal around the planet! That's why there's a lot of interest from companies looking to capture and return space debris, using techniques such as space networks, slingshots or solar sails.
What are all these satellites doing?
According to UCS, the main objectives of operational satellites are:
- Communications - 713 satellites
- Earth observation/science - 374 satellites
- Technology demonstration/development using 160 satellites
- Navigation & GPS - 105 satellites
- Space science - 67 satellites
It should be noted that some satellites have multiple purposes.
Who owns the Earth's satellites?
It is interesting to note that there are four main types of users in the UCS database, although 17% of satellites are owned by multiple users.
- 94 satellites registered civilians: they are usually educational institutions, although there are others national organizations. 46% of these satellites have the purpose of developing technologies such as Earth and space science. Observations account for another 43%.
- 579 belong to commercial users: commercial organizations and state organizations who want to sell the data they collect. 84% of these satellites are focused on communications and global positioning services; of the remaining 12% are Earth observation satellites.
- 401 satellites are owned by government users: mainly national space organizations, but also other national and international bodies. 40% of them are communications and global positioning satellites; another 38% is focused on Earth observation. Of the rest - development space science and technology is 12% and 10% respectively.
- 345 satellites belong to the military: again the focus here is communications, Earth observation and global positioning systems, with 89% of the satellites having one of these three purposes.
How many satellites do countries have?
According to UNOOSA, about 65 countries have launched satellites, although the UCS database only has 57 countries recorded using satellites, and some satellites are listed with joint/multinational operators. The biggest:
- USA with 576 satellites
- China with 181 satellites
- Russia with 140 satellites
- The UK is listed as having 41 satellites, plus participates in an additional 36 satellites operated by the European Space Agency.
Remember when you look!
Next time you look at the night sky, remember that between you and the stars there are about two million kilograms of metal surrounding the Earth!
Satellite is dense natural object which orbits the 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 only companion, but after the invention of the telescope, satellites of others were discovered. Each planet has one or more satellites, except Mercury and Venus. At Jupiter greatest number satellites - 67. Technological advances 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 - largest satellite 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 mainly composed of water ice and rock, and presumably has 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 does full turn 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 satellite of Jupiter and the third largest satellite in the 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, makes up most mass of the satellite. 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. The development of technology makes it possible for scientists to send spacecraft to different corners Solar System to get more information about the planets and their moons.
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 | Europe, 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 |
Satellites are small bodies that orbit planets. In the solar system, two planets (Mercury and Venus) have no satellites, the Earth has one, and Mars has two. A large number of satellites are attracted by the magnetic field of Neptune (13 satellites), Uranus (27 satellites), Saturn (60 satellites). But greatest number satellites of Jupiter. There are 63 of them! Now you know which planet has more satellites in the Solar System.
In addition to such a huge number of satellites, Jupiter also has a system of rings. The first 4 satellites of Jupiter, the largest, were discovered by Galileo at the beginning of the 17th century. He gave them the names Europa, Ganymede, Io, Callisto (names of mythical heroes). With the development of telescopic technology, the remaining satellites began to be discovered; in the 70s of the last century, 13 of them were discovered. At the beginning of the third millennium, 47 more satellites of Jupiter were discovered. They are quite small, their radius reaches 4 km. Who knows how many more planetary satellites will be discovered over time when scientific and technical progress humanity...
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Which planet has the most satellites?
The most a large number of Among the planets of the Solar System, the planet Jupiter has as many as 63 satellites. In addition to them, this planet also boasts a system of rings. The first 4 satellites were discovered back in the Middle Ages in the 17th century using a telescope, and the last (most of them) - at the end of the 20th century using spacecraft. The size of most of them is not too large - only 2 to 4 kilometers in diameter. A little fewer satellites Saturn has 60. But one of its satellites, Titan, is the second largest in the solar system and has a diameter of 5100 km.
The third largest number of satellites is Uranus. He has 27 of them. And planets such as Venus and Mercury have no satellites at all. 5-11-2010
Have you read the answer to the question Which planet has the most satellites? and if you liked the material, bookmark it - “Which planet has the most satellites?? . Which car is best for taxi work? This is controversial...
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At Jupiter...
Mercury has no satellites.
Venus also has no satellites
The Earth has one satellite: the Moon
The Moon is the only natural satellite of the Earth. It is the second brightest object in the earth's sky after the Sun and the fifth largest natural satellite in the solar system. Also, it is the first (and as of 2009 only) extraterrestrial object natural origin, which a person visited. The average distance between the centers of the Earth and the Moon is 384,467 km.
The planet Mars has two satellites: Phobos (Greek - fear) and Deimos (Greek - horror).
Both satellites rotate around their axes with the same period as around Mars, therefore they are always turned to the planet with the same side. The tidal influence of Mars gradually slows down the movement of Phobos, and will eventually lead to the fall of the satellite onto Mars. On the contrary, Deimos is moving away from Mars.
Jupiter has 63 moons
The moons of Jupiter are the natural satellites of the planet Jupiter. To date, scientists know 63...
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Central star Our system, around which all the planets pass in different orbits, is called the Sun. Its age is about 5 billion years. It is a yellow dwarf, so the size of the star is small. Her thermonuclear reactions They don't get used up very quickly. The solar system has reached approximately the halfway point of its life cycle. After 5 billion years, the balance of gravitational forces will be disrupted, the star will increase in size and gradually warm up. Thermonuclear fusion converts all of the sun's hydrogen into helium. At this point, the size of the star will be three times larger. Ultimately, the star will cool down and shrink. Today the Sun consists almost entirely of hydrogen (90%) and some helium (10%).
Today, the satellites of the Sun are 8 planets, around which other celestial bodies revolve, several dozen comets, as well as a huge number of asteroids. All these objects move in their orbit. If you add up the mass of all the solar satellites, it turns out that they are 1000 times lighter than their star....
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Natural satellites are relatively small cosmic bodies, which orbit larger “host” planets. Partly dedicated to them a whole science– planetology.
In the 70s, astronomers assumed that Mercury has several dependent celestial bodies, since they caught ultraviolet radiation around. Later it turned out that the light belonged to a distant star.
Modern equipment allows us to study the planet closest to the Sun in more detail. Today, all planetary scientists unanimously insist that it has no satellites.
Moons of the planet Venus
Venus is called Earth-like because they have similar compositions. But if we talk about natural space objects, then the planet named after the goddess of love is close to Mercury. These two planets in the solar system are unique in that they are completely alone.
Astrologers believe that Venus could have previously seen these, but to date not a single one has been discovered.
How many natural satellites does the Earth have?
Our native land there are many satellites, but only one natural one, which every person knows about from infancy - this is the Moon.
The size of the Moon is more than a quarter of the diameter of the Earth and is 3475 km. It is the only celestial body with such large dimensions relative to the “host”.
Surprisingly, its mass is small - 7.35 × 10²² kg, which indicates low density. Multiple craters on the surface are visible from Earth even without any special devices.
What moons does Mars have?
Mars is a fairly small planet that is sometimes called red because of its scarlet hue. It is given by iron oxide, which is part of its composition. Today, Mars boasts two natural celestial objects.
Both moons, Deimos and Phobos, were discovered by Asaph Hall in 1877. They are the smallest and darkest objects in our comic system.
Deimos is translated as the ancient Greek god who spreads panic and terror. Based on observations, it is gradually moving away from Mars. Phobos, bearing the name of the god who brings fear and chaos, is the only satellite that is so close to the “master” (at a distance of 6000 km).
The surfaces of Phobos and Deimos are abundantly covered with craters, dust and various loose rocks.
Moons of Jupiter
Today, the giant Jupiter has 67 satellites - more than other planets. The largest of them are considered an achievement Galileo Galilei, since they were discovered by him in 1610.
Among the celestial bodies orbiting Jupiter, it is worth noting:
- Adrasteus, with a diameter of 250 × 147 × 129 km and a mass of ~3.7 × 1016 kg;
- Metis - dimensions 60×40×35 km, weight ~2·1015 kg;
- Thebe, with a scale of 116×99×85 and a mass of ~4.4×1017 kg;
- Amalthea - 250×148×127 km, 2·1018 kg;
- Io with a weight of 9 1022 kg at 3660 × 3639 × 3630 km;
- Ganymede, which with a mass of 1.5·1023 kg had a diameter of 5263 km;
- Europe, occupying 3120 km and weighing 5·1022 kg;
- Callisto, with a diameter of 4820 km and a mass of 1·1023 kg.
The first satellites were discovered in 1610, some from the 70s to the 90s, then in 2000, 2002, 2003. The last of them were discovered in 2012.
Saturn and its moons
62 satellites have been found, of which 53 have names. Most of them are made of ice and rocks, characterized by a reflective feature.
The largest space objects of Saturn:
How many moons does Uranus have?
At the moment, Uranus has 27 natural celestial bodies. They are named after characters famous works, by Alexander Pope and William Shakespeare.
Names and list by quantity with description:
Moons of Neptune
The planet, whose name is similar to the name of the great god of the seas, was discovered in 1846. She was the first to be found using mathematical calculations, and not through observations. Gradually, new satellites were discovered until they counted 14.
List
Neptune's moons are named after nymphs and various sea deities from Greek mythology.
The beautiful Nereid was discovered in 1949 by Gerard Kuiper. Proteus is a non-spherical cosmic body and is studied in detail by planetary scientists.
Giant Triton is the iciest object in the solar system with a temperature of -240°C, and is also the only satellite rotating around itself in the direction opposite to the rotation of the “master”.
Almost all of Neptune's satellites have craters and volcanoes on their surface - both fire and ice. They spew from their depths mixtures of methane, dust, liquid nitrogen and other substances. Therefore, a person will not be able to stay on them without special protection.
What are “planetary satellites” and how many are there in the solar system?
Satellites are cosmic bodies that are smaller in size than the “host” planets and rotate in the orbits of the latter. The question of the origin of satellites is still open and is one of the key ones in modern planetology.
Today there are 179 natural space objects, which are distributed as follows:
- Venus and Mercury – 0;
- Earth – 1;
- Mars – 2;
- Pluto – 5;
- Neptune – 14;
- Uranium – 27;
- Saturn – 63;
- Jupiter - 67.
Technology improves every year, finding more celestial bodies. Perhaps new satellites will be discovered soon. We can only wait, constantly checking the news.
The largest satellite in the solar system
Ganymede, a satellite of the giant Jupiter, is considered the largest in our solar system. Its diameter, according to scientists, is 5263 km. The next largest is Titan with a size of 5150 km - the “moon” of Saturn. The top three is closed by Callisto, the “neighbor” of Ganymede, with whom they share one “master”. Its scale is 4800 km.
Why do planets need satellites?
Planetologists have always asked the question “Why are satellites needed?” or “What effect do they have on the planets?” Based on observations and calculations, some conclusions can be drawn.
Natural satellites play important role for the "owners". They create a certain climate on the planet. No less important is the fact that they serve as protection against asteroids, comets, and other dangerous celestial bodies.
Despite such a significant impact, satellites are still not necessary for the planet. Even without their presence, life can form and sustain on it. This conclusion was reached by the American scientist Jack Lissauer from the scientific space center NASA.