The complex structure of the cosmos and the processes taking place in the depths of the Universe, man began to learn in ancient times. Many secrets have already been revealed, but cosmos still keeps most of its mysteries in its remote corners.
In our short review, we already know the knowledge about space objects that rotate around other, larger planets under the force of gravity.
The term "satellite" was first used as early as 1611 by Johannes Kepler. There are countless such satellites in outer space, but we will consider the largest satellites in the review. We begin our journey with the "giants" of the solar system.
The largest satellites of the solar system
Iapetus
In the photo: mountain range, encircling satellite
Our rating opens with a satellite revolving around Saturn, and named after the ancient Greek titan. It was opened in 1671 by Giovanni Cassini. Today, the scientific world and the public know that the diameter of Iapetus is equal to 1468 kilometers.
Comparative sizes of the Earth, Moon and Iapetus
On it with the help of spacecraft unique mountain ranges were recorded in the entire solar system. A chain of mountains 13 kilometers high surrounds the satellite equator.
Another feature is the two-facedness of Iapetus. One side is black and the other is bright. But the border between them passes not in a straight line, but in a somewhat curved line.
Oberon
The orbit of this satellite, also called Uranus IV, is removed from the center of Uranus at the greatest distance among all the satellites of the planet.
It was discovered by space explorer William Herschel in 1787. But they named a satellite with a diameter of 1523 kilometers in honor of the king of elves and fairies.
The surface of Oberon is rather dark, but it was possible to examine unique objects on it - craters and canyons. They are named, like the satellite itself, in honor of the mythical and historical heroes mentioned in the works of Shakespeare and Alexander Pope.
Rhea
The satellite, which received its beautiful name in honor of the titanides of Rhea, revolves around Saturn. Although Cassini, who discovered it in 1672, called the satellite of one of the stars of King Louis XIV.
The diameter of the ice satellite is 1529 kilometers, and, like many objects of the Cosmos, has a dark and bright side. Using the aircraft of the Cassini project, it was possible to find out that Rhea has an atmosphere consisting of oxygen and carbon dioxide.
Craters and canyons on the surface are gradually smoothed, filling with ice. Scientists also suggested that the mother of the Olympic gods Rhea may have their own rings.
Titania
The satellite, named after the goddess of fairies from Shakespeare's comedy, revolves around Uranus and has a diameter of 1,578 kilometers. It was discovered by William Herschel, but the name was given already by his son John.
The orbit of Titania is almost circular and has almost no inclination to the equator. On the surface there are three types of reliefs represented by craters, ledges by canyons. In addition, it has frozen water and carbon dioxide.
Its surface is dark with a reddish tint, and the relief was formed both under external influence and internal processes. The only clear and large image was made by the Voyager 2 apparatus, which NASA launched to explore Space in 1977.
Triton
Named after the son of Poseidon, the satellite revolves around Neptune - the eighth planet of the solar system, and its diameter is 2707 kilometers. The discovery of Neptune and its satellite is only 17 days apart. In 1846, an object near the planet was seen by British astronomer William Lassel.
It is the only one having a retrograde orbit, and rotates in the opposite direction from the rotation of Neptune. For a long time, scientists of the world took it for a planet, due to the unique structure and physical characteristics.
Covered with ice from methane and nitrogen, reflecting sunlight well. But at the south pole fit a huge polar cap, an unusual pinkish-yellow color.
Europe
The great satellite of Jupiter received the romantic and beautiful name Europe, in honor of the daughter of the Phoenician king, whom Zeus himself fell in love with. This name was given to a satellite with a diameter of 3122 kilometers by Simon Marius, and he discovered "Europe" by Galileo.
It has the most even surface, and also one of the brightest among all satellites. In the photo of Europe, multiple lines are visible on its surface. These are faults and cracks in the ice shell, which make its images unique and unusual.
But besides these geological objects there are also mountain ranges and craters left over from collisions with meteorites.
Moon
Scientists suggest that the satellite of our wonderful planet formed about 4.5 billion years ago, but the hypotheses of the origin of the moon are countless.
A satellite with a diameter of 3475 kilometers affects some processes on Earth, including the tides of the seas and oceans. And the first calendar used by Mankind was Lunar.
In the photo: This is a real frame in which we can simultaneously see both the Earth and the Moon.
This is the only cosmic object in the universe that man has visited. In addition, the Moon is considered the planet’s closest satellite to the Sun, since neither Venus nor Mercury have their own satellites.
And about
Artistic depiction of a likely landscape on Io
The closest satellite located to the surface of Jupiter, has a diameter of 3643 kilometers. And they named him after the priestess of Hera.
This is the most geologically active object of the solar system, since more than 400 active volcanoes are evenly located on the surface of Io. This is due to proximity to the mother planet, the gravitational field of which actively affects the bowels of its satellite.
It, like many other satellites, was discovered by Galileo, and active exploration of Io began in the late 70s of the last century.
Callisto
In 1610, this magnificent satellite of Jupiter was discovered by Galileo Galilei, but the name in honor of his beloved Zeus was given to him by the German astronomer Simon Marius.
We examined an object with a diameter of 4821 kilometers during the American space projects Pioneer and Voyager. It was these spacecraft that provided invaluable information about the structure and physical characteristics.
Like the satellite of the Earth, Callisto is always facing his planet on one side, since the period of revolution in orbit is equal to revolution around its own axis.
Titanium
The largest satellite of Saturn, named due to its size as Titan, occupies an honorable second place in the series of large satellites. Its diameter is 5150 kilometers, and it was discovered by the Dutch astronomer Christian Huygens in 1655.
The only satellite of our system on which scientists accurately confirmed the presence of liquid water, as on Earth. But the atmosphere, with a thickness of more than 400 kilometers, consists of nitrogen, and presses on the surface of Titan 1.5 times more pressure than atmospheric pressure on Earth.
Titanium is very cold, because the temperature is -180 degrees Celsius.
Ganymede
So it's time to introduce the largest satellite of the Solar System, which revolves around the enchanting Jupiter. The diameter of the object included in the group of Galilean satellites is 5,268 kilometers.
Scientists suggest that under the 200-kilometer thick ice in the depths of Ganymede there is an ocean in which there is many times more water than on Earth.
This satellite was discovered by Galileo Galilei, and the name in honor of the son of King Troy was already given to him by Kepler. Note that this is the only satellite of Jupiter named after a man.
Some facts about the satellites of the Solar System
- Two satellites of Mars Deimos and Phobos were predicted long before their actual discovery. Both are associated with fear.
- Pluto's companion, Charon, bears the name of a mythological hero transporting people across the Styx River of Death.
- To date, scientists have discovered 154 satellites in the Solar System, 115 of them have their own names, and the rest are only temporary alphanumeric designations.
It is interesting that by studying cosmic objects, you can simultaneously study Greek and Roman mythology, as well as the history of Mankind, since the planets of the solar system bear the names of mythical heroes and pagan deities.
The largest satellites in the universe
It's time to learn about the largest exolunas known to date. It is likely that many of the planets in the universe have natural satellites, but today the search for these moons is a difficult task for humanity.
More recently, we only learned how to find planets in other stellar systems, and the search for satellites of these planets is even more complicated. Nevertheless, the scientific community has a small list of candidates for probable exoluns.
Planet satellite Kepler-1625b
At 4,000 light-years away, the exoplanet Kepler-1625b revolves around a yellow star. This is a gas giant with a radius of 5-12 times the radius of Jupiter. In 2017, a possible satellite of this planet was found using the Kepler telescope using the transit method.
According to preliminary estimates, the satellite is 20 radii from the host and has the size of Neptune. How do you like this moon? It is very interesting that the planet (and satellite) are in the habitat zone.
MOA-2011-BLG-262L
The status of this double object is still in question. But there are two main versions.
The first version says that it is a red dwarf with a mass of 10% solar, around which the planet rotates 17-18 times heavier than the Earth. But we are interested in the second version, which seems more believable.
Proponents of the second version claim that the double object is nothing but a planet wandering in interstellar space with a mass of 3 to 4 Jupiter masses, around which a satellite weighs half the size of the earth. TheBiggest.ru hopes that in the near future the status of these facilities will be precisely determined.
WASP-12 b 1
In 870 light years from us there is a star that, like two drops of water, is similar to our Sun. Today we know that at least one planet revolves around this star. TheBiggest.ru once mentioned it in an article about the largest planets, this is WASP-12 b - a gas giant 1.74 times the size of Jupiter, which rotates around the star at a distance of 0.025 AU, which is 40 times less than the distance between the earth and the sun.
We also know that around this exoplanet a satellite rotates with a radius of 0.57 of the radius of Jupiter (it is 6.4 times the size of the Earth). Today it is the largest known satellite in the universe.
Authors of the article: Valery Skiba, Alexey Shcherbakov