general information

The dimensions of Titan in diameter are 5152 km, as a result of which it is larger than the Moon and in diameter by about 50%. Christian Huygens, being a famous Dutch physicist, mechanic, mathematician and astronomer, discovered Titan as the first moon of Saturn in 1655.

Astronomers for a long time believed that its diameter is 5550 km, and he ranked first. The true dimensions were found out later thanks to the Voyager 1 apparatus.

The surface of this huge moon

Until 2004, scientists did not know what the surface of this unexplored celestial body looked like, because. Titan, a moon of Saturn, was completely enveloped in an incredibly dense shell of the atmosphere, making it difficult to study. But after the landing of the Cassini-Huygens apparatus on its surface, all questions were resolved.

At the moment, it is known that its surface is still quite young by geological standards, and it is covered with sedimentary organic matter and water ice. It is almost all flat, except for a few mountains and craters. The surface temperature is 170-180°C below zero. The atmosphere is mainly nitrogen, with some ethane and methane.

The hydrocarbon sea of ​​Ligeia is the second largest, Cassini radar imagery

Significant areas of the surface are covered with ethano-methane rivers and lakes. On this celestial body, scientists discovered a liquid and proved the presence of an atmosphere, as a result of which a hypothesis was presented that a primitive form of life could exist on Titan.

physical characteristics

A share of 95% in the total mass of all satellites surrounding Saturn belongs to Titan. The debate about where such a huge satellite came from has led to several theories, but scientists have not yet come to a final answer. One theory is as follows: this celestial body could have been formed from a dust cloud, which was subsequently captured by the planet's gravity. At the same time, this theory also explains such a large difference in the mass of satellites.

Orbit of motion

The orbit of the second largest satellite in the solar system is 1221,870 km, which is equal to 20.3 Saturn radii, as a result it is located outside the rings of Saturn. It makes one full circle around the planet in almost 16 days. At the same time, its speed is 5.57 kilometers per second.

Titan, like the Moon, rotates synchronously around its planet. It is precisely because the revolutions around Saturn and around its own axis that Titan coincides, he always looks at the planet with the same side. The trajectory of Saturn's rotation is inclined with respect to the ecliptic by 26.73′, it is this moment that ensures the change of seasons on the planet itself and its satellites.

Each of the seasons has a duration of approximately 7.5 Earth years, while Saturn itself makes one revolution around the Sun, in about 30 years. Based on this, it can be assumed that the last summer on Titan ended in 2009.

And finally, some of the most spectacular photos of Titan

For that category of enthusiastic scientists who are interested in the existence of extraterrestrial worlds suitable for exploration, the well-known phrase: “Is there life on Mars, is there life on Mars”, has ceased to be relevant today. It turned out that within the solar system there are worlds that are much more interesting in this aspect than the Red Planet. A striking example of this is the largest satellite of Saturn, Titan. It turned out that this celestial body is very similar to our planet. The information that scientists have today admits the existence of a scientific version that life on Titan, a satellite of Saturn, is a very real fact.

Why is Titan so interesting for earthlings?

After decades of trying unsuccessfully to find a world within our solar system that even remotely resembled our Earth, information about Titan gave hope to the scientific community. Scientists became interested in this celestial body since 2005, when the Huygens automatic probe landed on the surface of one of the largest satellites in the solar system. Over the next 72 minutes, the onboard photo and video camera of the spacecraft transmitted to Earth a photo of the surface of this object and other video materials about this distant world. Even in such a limited time allotted for instrumental studies of a distant satellite, scientists were able to obtain an exhaustive amount of information.

Landing on the surface of Titan was carried out as part of the international Cassini-Huygens program aimed at studying Saturn and its satellites. Launched back in 1997, the Cassini robotic interplanetary station is a joint development of ESA and NASA for a detailed study of Saturn and the surrounding area of ​​\u200b\u200bthis planet. After 7 years of flight across the expanses of the solar system, the station delivered the Huygens space probe to Titan. This unique spacecraft is the result of a joint effort between NASA and the Italian space agency, whose team had high hopes for this flight.

The results that scientists received from the operating Cassini station and from the Huygens probe turned out to be invaluable. Despite the fact that a distant satellite appeared before the gaze of earthlings as a huge silent realm of ice, the subsequent detailed study of the surface of the object changed the idea of ​​​​Titan. In the pictures taken with the help of the Huygens probe, it was possible to make out in great detail the surface of the satellite of Saturn, which mainly consisted of solid water ice and sedimentary layers of an organic nature. It turned out that the dense and impenetrable atmosphere of a distant satellite has almost the same composition as the earth's air-gas shell.

In the future, Titan threw scientists another serious bonus. For the first time in the history of the development and study of extraterrestrial space outside the Earth, liquid matter of the same nature was found that was on the planet Earth in the early years of its existence. The relief of the celestial body is complemented by a huge ocean, numerous lakes and seas. All this gives reason to believe that we are dealing with a celestial body, which could be another oasis of life in our solar system. Studies of the composition of the atmosphere and liquid medium of the satellite of Saturn revealed the presence of useful substances necessary for the life of organisms. It is assumed that under certain conditions in the process of studying this celestial body, living organisms can be found on Titan.

In this regard, the subsequent study of the largest satellite of Saturn becomes relevant. It is highly likely that, along with Mars, it is Titan that can become the second space home for human civilization.

Academic view of Titan

The size of Titan allows it to compete with the planets of the solar system. This celestial body has a diameter of 5152 km, which is greater than the diameter of Mercury (4879 km) and slightly smaller than Mars (6779 km). The mass of Titan is 1.3452 1023 kg, which is 45 times less than the mass of our planet. By its mass, the satellite of Saturn is the second in the solar system, yielding to the satellite of Jupiter - Ganymede.

Despite its impressive size and weight, Titanium has a low density, only 1.8798 g/cm³. For comparison, the density of the parent planet Saturn is only 687 c/m3. Scientists have identified a weak gravitational field in the satellite. The force of attraction on the surface of Titan is 7 times weaker than the earth's parameters, and the acceleration of free fall is the same as on the Moon - 1.88 m/s2 versus 1.62 m/s2.

A characteristic feature is the position of Titan in space. The largest satellite of Saturn revolves around its parent planet in an elliptical orbit at a speed of 5.5 km / s, being outside the region of Saturn's rings. The average distance from Titan to the surface of Saturn is 1.222 million km. This entire system is located at a distance of 1 billion 427 million km from the Sun, which is 9.5 times the distance between our central star and the Earth.

Like our satellite, the “Moon of Saturn” is always turned to it with one side. This is due to the synchronism of the satellite's rotation around its own axis with the period of Titan's revolution around the mother planet. Its largest satellite makes a complete revolution around Saturn in 15 Earth days. Due to the fact that Saturn and its satellites have a fairly high angle of inclination of the axis of rotation to the axis of the ecliptic, there are seasons on the surface of Titan. Every 7.5 Earth years on the satellite of Saturn, summer is replaced by a cold winter period. According to astronomical observations, autumn is on the side of Titan that faces Saturn today. Soon the satellite will hide from the sun's rays behind the mother planet and the Titanic autumn will be replaced by a long and fierce winter.

Temperatures on the surface of the satellite vary between minus 140-180 degrees Celsius. Data obtained from the Huygens space probe revealed a curious fact. The difference between polar and equatorial temperatures is only 3 degrees. This is explained by the presence of a dense atmosphere, which prevents the impact of sunlight on the surface of Titan. Despite the high density of the atmosphere, there is no liquid precipitation on Titan due to low temperatures. In winter, the surface of the satellite is covered with snow from ethane, particles of water vapor and ammonia. This is only a small part of what we know about Titan. Interesting facts about the largest satellite of Saturn concern literally any field, from astronomy, climatology and glaciology to microbiology.

Titan in all its glory

Until recently, most of the information about Saturn's moon was based on visual observations obtained from the Voyager space probe, which raced past it at a distance of 7000 km in 1980. The Hubble telescope slightly opened the veil of secrecy about this space object. To get an idea of ​​the surface of the satellite did not allow its dense atmosphere, which in density and thickness is second only to the Venusian and terrestrial air-gas shell.

The mission of the Cassini automatic station in 2004 helped to remove the veil of fog that reigned over this celestial body. For four years, the device was in orbit of Saturn, carrying out sequential photography of its satellites, including Titan. Research from the Cassini probe was carried out using a camera with an infrared filter and a special radar. The photographs were taken from different angles at a distance of 900-2000 km from the satellite surface.

The culmination of the study of Titan was the landing on its surface of the Huygens probe, named after the discoverer of Saturn's moon. The apparatus, having entered the dense layers of the atmosphere of Titan, descended by parachute for 2.5 hours. During this time, the probe equipment studied the composition of the satellite's atmosphere, photographed its surface from a height of 150, 70, 30, 15 and 10 kilometers. After a long descent, the space probe landed on the surface of Titan, burrowing 0.2-0.5 meters into the dirty ice. After landing on the moon, Huygens worked for a little more than an hour, transmitting to Earth through the Cassini AMS a lot of useful information directly from the surface of the satellite. Thanks to images taken from the Cassini spacecraft and the Huygens probe, a team of researchers has compiled a map of Titan. In addition, scientists now had detailed information about its atmosphere, data on the climate on the surface and features of the relief.

satellite atmosphere

In the situation with Titan, for the first time in the process of studying and studying the celestial bodies of the solar system, scientists had the opportunity to study the atmosphere in detail. As expected, the satellite of Saturn has a dense and well-developed atmosphere, which not only resembles the gaseous shell of the Earth in many respects, but also surpasses it in mass.

The thickness of the atmospheric layer of Titan was 400 km. Each layer of the atmosphere has its own composition and concentration. The gas composition is as follows:

• 98.6% leaves nitrogen N;
• 1.6% in the atmosphere is methane;
• a small amount of ethane, acetylene compounds, propane, carbon dioxide and carbon monoxide, helium and cyan.

The concentration of methane in the atmosphere of the satellite, starting from a height of 30 km, changes in the direction of decrease. As you approach the surface of the satellite, the amount of methane decreases to 95%, but the concentration of ethane increases to 4-4.5%.

A characteristic feature of the air-gas layer of the Titan satellite is its anti-greenhouse effect. The presence of hydrocarbon organic molecules in the lower layers of the atmosphere neutralizes the greenhouse effect created by a huge concentration of methane. As a result, the surface of the celestial body cools evenly due to the presence of hydrocarbons. The same processes and the gravitational field of Saturn determine the circulation of the atmosphere of Titan. Such a picture contributes to the formation of active climatic processes in the atmosphere of Saturn's moon.

It should be noted that the atmosphere of the satellite is constantly losing weight. This is due to the absence of a powerful magnetic field in the celestial body, which is not able to hold the air-gas shell, which is under the constant influence of the solar wind and the gravitational forces of Saturn. To date, the atmospheric pressure on the satellite of the ringed giant is 1.5 atm. This is invariably reflected in weather conditions, which change with the concentration of gases in Titan's atmosphere.

The main work on creating weather on Titan is performed by dense clouds, which, unlike terrestrial air masses, consist of organic compounds. It is these atmospheric formations that are the source of precipitation on the largest satellite of Saturn. Due to low temperatures, the atmosphere of the celestial body is dry. The highest concentration of cloudiness was found in the polar regions. Due to low temperatures, the humidity in the atmosphere is extremely low, so the precipitation on Titan is methane ice crystals and frost, consisting of compounds of nitrogen, ethane and ammonia.

The surface of Titan and its structure

Saturn's satellite has not only an interesting atmosphere. Its surface is an extremely curious object from the point of view of geology. Under a thick blanket of methane, the photographic lenses and cameras of the Huygens space probe discovered entire continents, separated by numerous lakes and seas. As on Earth, there are plenty of rocky and mountain formations on the continents, there are deep crevices and depressions. They are replaced by vast plains and valleys. In the equatorial part of the celestial body, a vast area of ​​dunes was formed by particles of hydrocarbonate and water ice. It is assumed that the Huygens space probe landed on one of these dunes.

The complete resemblance to a living planet adds the presence of a liquid structure. On Titan, rivers have been discovered that have sources, winding channels and deltas - places where streams flow into sea basins. According to the data taken from the images, some of the rivers of Titan have a channel length of more than 1000 km. Almost all of the liquid mass of Titan is concentrated in sea basins and lakes, which occupy an impressive area - up to 30-40% of the entire surface area of ​​this celestial body.

Evidence of the presence of large accumulations of liquid medium on the surface of the satellite was a huge bright spot, which for a long time confused astronomers. Subsequently, it was proved that the bright region on Titan is a huge pool of liquid hydrocarbons, called the Kraken Sea. By area, this imaginary body of water is larger than the largest lake on Earth - the Caspian Sea. Another equally interesting object is the Ligeia Sea - the largest natural reservoir for liquid methane and ethane.

Accurate information about the composition of the liquid environment of the seas and lakes of Titan was obtained thanks to the work of the Casssini AMS. Using data from photographs and computer simulations, the composition of the liquid on Titan was determined under terrestrial conditions:

• ethane is 76-80%;
• propane in the seas and lakes of Titan 6-7%;
• methane accounts for 5-10%.

In addition to the main elements, presented in the form of frozen gases, hydrogen cyanide, butane, butene and acetylene are present in the liquid. The main accumulation of water on Titan has a nature somewhat different from the earth's form. Huge deposits of superheated ice, consisting of water and ammonia, were found on the surface of the satellite. It is assumed that under the surface there may be extensive natural reservoirs filled with liquid water with ammonia dissolved in it. In this aspect, the internal structure of the satellite is also interesting.

Today, various versions are being put forward about the internal structure of Titan. As is the case with all the planets of the terrestrial group, it has a solid core, not iron-nickel, as on the first four planets of the solar system, but stone. Its diameter is approximately 3400-3500 km. Then the most interesting begins. Unlike the Earth, where the mantle begins after the core, on Titan this space is filled with dense compressed layers of water ice and methane hydrate. Probably, there is a liquid layer between the individual layers. However, despite its coldness and stone nature, the satellite is in an active phase and tectonic processes are observed on it. This is facilitated by tidal forces, which are caused by the giant gravity of Saturn.

Possible future of Titan

Judging by the data of studies conducted in the last decade, humanity is dealing with a unique object in the solar system. It turned out that Titan is the only celestial body, in addition to the Earth, which is characterized by all three types of activity. On the satellite of Saturn, traces of constant geological activity are observed, which are confirmation of its living tectonic activity.

To a large extent, the nature of the surface of Titan is also interesting. Its structure, composition and relief speak in favor of the fact that the surface of Saturn's moon is in constant motion. Here, as on Earth, under the influence of winds and precipitation, soil erosion is observed, rocks are weathered and sediments are deposited.

The composition of the satellite's atmosphere and the circulation processes occurring in it shaped the climate on Titan. All of these signs speak in favor of the fact that life can exist on Titan under certain conditions. Naturally, it will be a form of life different from terrestrial organisms, but its very existence will be a colossal discovery for mankind.

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Detail:

Satellites of Saturn

Titanium

© Vladimir Kalanov,
website"Knowledge is power".

Dozens of satellites revolve around Saturn. Currently, 53 named satellites are known, about a dozen celestial bodies are "awaiting" confirmation of their flight trajectories for involvement in the satellite system of Saturn. Among them, the largest satellite stands out - Titan, discovered, as you know, already in 1655 by Christian Huygens. In terms of size, Titan ranks second among all the satellites of the solar system, second only to Ganymede, the satellite of Jupiter. The diameter of Titan is 5150 km, i.e. in size, this satellite is larger than the planet Mercury, whose diameter is 4878 km. The orbital period of Titan around Saturn is almost 16 days (15 days, 22 hours and 41 minutes). Titan is turned to Saturn on one side, like the Moon to the Earth. Titan moves in its orbit at a distance of 1221900 km from Saturn.

The internal structure of Titan

Titan is of great interest not only to astronomers, but also to biologists, geologists and paleoclimatologists. But all of them are interested not only and not so much in the size of Titan and the parameters of its orbit, as in the atmosphere and surface of this satellite.

Titan is the only moon in the solar system that has an atmosphere. The density of Titan's atmosphere is much higher than the density of the earth's atmosphere, so the pressure at the level of the surface of Titan is one and a half times (1.5 bar) higher than the earth's. The temperature on the surface of the satellite is in the range from 90 to 100 K. The atmosphere consists mainly of nitrogen (90-97%), there are also methane (2-5%) and argon (about 0-6%), there are traces of ethane, hydrogen ( 0.2%) and carbon dioxide. The presence of methane was already determined in 1944 using infrared spectrometry.

The surface of Titan is covered with clouds. In images transmitted in 1980 by Voyager 1, the clouds are predominantly orange. This means the presence of organic molecules in them, which is quite understandable in the presence of methane in the atmosphere. Methane is a greenhouse gas, and clouds containing methane densely cover the surface of Titan. Visual observations of Titan are very difficult. Some researchers have suggested that cold reigns only in the outer layers of the atmosphere, and there may be other conditions on the surface, including those under which protein life is possible.

There was an assumption about the similarity of the titanic atmosphere with the atmosphere that previously existed on Earth. This assumption had a certain basis, because. in the modern atmosphere of the Earth, as in the atmosphere of Titan, the main component is molecular nitrogen.

Titan's Surface Mystery

Panoramic view of the surface of Titan from the spacecraft "Huygens"

The mystery of the surface of Titan haunted scientists. Astronomers, and especially biologists and paleoclimatologists, wanted to learn more about the celestial body, on which (what if!) Protein life could be found. What is there, under a layer of clouds: the ocean or a solid surface? If the ocean, what is it filled with - water? ethane? It didn't take long for these questions to be answered. In 1997, NASA, together with the European Space Agency, completes the development of the Cassini-Huygens project and the Cassini interplanetary apparatus with the Huygens atmospheric probe starts to Titan. In July 2004, the Huygens probe separates from the Cassini spacecraft, enters Titan's cloudy atmosphere and lands on its surface. The information that the Huygens probe transmitted to Earth left no chance for researchers who dreamed of finding at least traces of biological activity on Titan. Once again, we are convinced that in the solar system, and possibly in our entire Galaxy and even in thousands of such galaxies, life does not exist anywhere except our beautiful small planet Earth. Titan's surface, like its atmosphere, was exceptionally cold, with an average surface temperature of minus 178°C. There are many lakes on its surface, but they are naturally filled not with water, perhaps they are compounds of methane or ethane with other substances.

The study of Titan continues. To date, over 60% of Titan's surface has been mapped. Lakes occupy about 14% of the entire studied area. The density of Titan's substance (a mixture of rock and ice) is about 1.88 g/cm³, which is the highest density among Saturn's moons. Titan accounts for more than 95% of the mass of all Saturn's moons. The mass of Titan is 1.345 × 10 23 kg. The free fall acceleration is 1.352 (m/s²), i.e. gravity is about seven times less than on Earth.

© Vladimir Kalanov,
"Knowledge is power"

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Saturn's moon is Titan, the most Earth-like celestial body. More recently, scientists have received a picture in which, for the first time, matter in a liquid state was discovered outside the Earth. In addition, an atmosphere similar to that of Earth was discovered on Titan. Previously, high-profile scientific discoveries have already been associated with Titan, for example, in 2008, an underground ocean was discovered on Titan. Perhaps it is Titan, and not Mars, that will become our future home.

Titan is the second largest moon in the solar system after Ganymede. Titan contains 95% of the mass of all Saturn's moons. The gravity on Titan is about a seventh of Earth's gravity. Titan is the only moon in the solar system to have a dense atmosphere, and the only moon whose surface is almost impossible to see due to the thick layer of clouds. The pressure at the surface is 1.6 times higher than the pressure of the earth's atmosphere. Temperature - minus 170-180 °C


Titan has seas, lakes, and rivers made of methane and ethane, as well as mountains made of ice. Probably, around the stone core, about 3400 km in diameter, there are several layers of ice with different types of crystallization and possibly a layer of liquid. A number of scientists have put forward a hypothesis about the existence of a global subsurface ocean. Comparison of Cassini images from 2005 and 2007 showed that landscape details were shifted by about 30 kilometers. Since Titan is always turned to Saturn on one side, such a shift can be explained by the fact that the icy crust is separated from the main mass of the satellite by a global liquid layer. The movement of the crust can cause the circulation of the atmosphere, which rotates in one direction (from west to east) and drags the crust with it. If the movement of the crust turns out to be uneven, then this will confirm the hypothesis of the existence of the ocean. Presumably it consists of water with ammonia dissolved in it.


This theory was confirmed by a picture of sunlight reflecting off the surface of Titan taken in mid-July 2009 by the Cassini spacecraft. The image was only publicly presented in December 2009, at the annual meeting of the American Geophysical Society in San Francisco.

After that, scientists had to spend a lot of time to prove that the detected bright spot is nothing more than a sun glare on the surface of the lake, and not a volcanic eruption or lightning. As a result of further analysis, scientists were able to find out that the detected glare belonged to the huge hydrocarbon basin of the Kraken Sea, the area of ​​\u200b\u200bwhich is 400 thousand square kilometers, which is larger than the area of ​​the largest lake on Earth - the Caspian Sea. According to Cassini data and computer calculations, the composition of the liquid in the lakes is as follows: ethane (76-79%). In second place is propane (7-8%), in third - methane (5-10%). In addition, the lakes contain 2-3% hydrogen cyanide, and about 1% butene, butane and acetylene. According to other hypotheses, the main components are ethane and methane.

The presence of lakes of liquid hydrocarbons on the surface of Titan has not been in doubt since the signs of huge lakes of liquid were discovered by Cassini in the process of studying the surface of Titan using radio waves. Scientists, based on these indirect data, even managed to prove the presence of cycles of global glaciations and thaws on Titan, but so far astronomers have not been able to break through the dense hydrocarbon atmosphere of Titan to capture these lakes. For the first time, the team of researchers working with Cassini managed to do this only now, when winter ended in the northern hemisphere of Titan, where most of the lakes are concentrated, and its surface began to be illuminated again by the rays of the Sun.


"It's amazing how much the surface of Titan resembles Earth," Pasadena-based planetary geologist Rosalie Lopez said in August after studying Titan's surface in detail.


Titan has an atmosphere, which also makes it similar to Earth. Titan's atmosphere is about 400 kilometers thick and contains several layers of hydrocarbon smog, making Titan the only satellite in the solar system whose surface cannot be observed with a telescope. Smog is also responsible for the anti-greenhouse effect unique to the solar system. The atmosphere is 98.6% nitrogen, and in the near-surface layer, its content decreases to 95%. Thus, Titan and the Earth are the only bodies in the solar system with a dense atmosphere and a predominant content of nitrogen. The diagram shows the structure of Titan. In continuation of this topic, I advise you to read about the trip to Mars and Elon Musk's Space X project, which plans to make life on Mars a reality.

Titan receives very little solar energy in order to ensure the dynamics of atmospheric processes. It is likely that the powerful tidal influences of Saturn provide energy for moving atmospheric masses, 400 times stronger than the tides caused by the Moon on Earth. The latitudinal location of dune ridges, which are widespread on Titan, speaks in favor of the assumption of a tidal nature of the winds. The surface of Titan at low latitudes was divided into several bright and dark regions with clear boundaries. Near the equator on the leading hemisphere, there is a bright region the size of Australia (also visible in Hubble photographs), which is a mountain range. It was named Xanadu.

Satellite name: Titanium;

Diameter: 5152 km;

Pov area: 83,000,000 km²;

Volume: 715.66×10 8 km³;

Weight: 1.35×1023 kg;

Density be: 1880 kg/m³;

Rotation period: 15.95 days;

Period of circulation: 15.95 days;

Distance from Saturn: 1,161,600 km;

Orbital speed: 5.57 km/s;

equator length: 16,177 km;

Orbital inclination: 0.35°;

Accel. free fall: 1.35 m/s²;

Satellite : Saturn

Titanium- the largest satellite of Saturn, as well as the second largest satellite in the solar system. For a long time it was believed that Titan is the largest moon in the solar system. Since modern research, scientists have paid attention to the size of Jupiter's moon Ganymede, which has a radius (2634 km) 58 km larger than that of Titan (2576 km). Saturn's satellite is not only larger than the rest of the moons, but even some of the planets. For example, the radius of the first planet from the Sun Mercury is 2440 km, which is 136 km less than the radius of Titan, and the last planet in the solar system is Pluto, 10 less in volume than the satellite. Titan size among the planets it is close to Mars (radius 3390 km), and their volumes are in the ratio 1:2.28 (in favor of Mars). In addition, Titan is the densest body among all Saturn's moons. And the mass of the largest moon is greater than the other satellites of Saturn combined. Titan accounts for more than 95% of the mass of all Saturn's moons. This is a bit like the ratio of the mass of the Sun to all other bodies in the solar system. Where the mass of the star accounts for more than 99% of the mass of the entire solar system. Density and Mass Titanium 1880 kg / m³ and 1.35 × 10 23 kg is similar to Jupiter's satellites - Ganymede (1936 kg / m³, 1.48 × 10 23 kg) and Callisto (1834 kg / m³, 1.08 × 10 23 kg).
Titan is the twenty-second moon of Saturn. Its orbit is farther than Dione, Tethys, and Enceladus, but nearly three times closer than Iapetus's. Titan is located outside the rings of Saturn at a distance of 1,221,900 km from the center of the planet and no closer than 1,161,600 km from the outer layers of Saturn's atmosphere. The satellite makes a complete revolution in almost 16 Earth days, or rather in 15 days 22 hours and 41 minutes with an average speed of 5.57 km / s. This is 5.5 times faster than the rotation of the Moon around the Earth. Like the Moon and many other planetary satellites in the solar system, Titan has a synchronous rotation relative to the planet, resulting from the action of tidal forces. This means that the periods of rotation around its axis and revolution around Saturn coincide, and the satellite is always turned to the planet by the same side. On Titan, as on Earth, there is a change of seasons, since the axis of rotation of Saturn is tilted relative to its equator by 26.73 °. Nevertheless, the planet is so distant from the Sun (1.43 billion km) that such climatic seasons last 7.5 years each. That is, Winter, Spring, Summer and Autumn on Saturn and its satellites, including Titan, alternate every 30 years - that is how much time is needed Saturian system to completely wrap around the sun.

Titan, like all other large satellites of the solar system, was discovered in the Middle Ages. Although the optics and telescopes of that time were much inferior to modern ones, nevertheless, on March 25, 1655, the astronomer Christian Huygens managed to notice a bright body next to Saturn, which, as he established, every 16 days appears in the same place on the disk of Saturn and therefore wraps around the planet. After four such revolutions, in June 1655, when the rings of Saturn had a low inclination relative to the Earth and did not interfere with observation, Huygens was finally convinced that he had discovered Saturn's satellite. This was the second discovery of a satellite since the invention of the telescope, 45 years after the discovery. Galileo the four largest moons of Jupiter. For nearly two centuries, the satellite had no specific name. The real name of Titan was proposed by John Herschel, an English astronomer and physicist in 1847, in honor of Kronos' brother, Titan.

The size of Titan (bottom left) compared to the Moon (top left) and Earth (right).

Titan is 15 times smaller than Earth and 3.3 times larger than the Moon

Atmosphere and climate

Titan is the only satellite in the solar system that has a fairly dense and thick atmosphere. It ends at an altitude of about 400 km from the surface of the satellite, which is 4.7 times higher than the atmosphere of the Earth (the conditional boundary between the air shell of the Earth and space is taken Karman line at an altitude of 85 km from the Earth's surface). The atmosphere of Titan has an average mass of 4.8 × 10 20 kg, which is almost 100 times heavier than Earth's air (5.2 × 10 18 kg). However, due to weak gravity, the free fall acceleration on the satellite is only 1.35 m / s² - 7.3 times weaker than Earth's gravity, and therefore, as the pressure decreases at the surface of Titan, it rises only to 146.7 kPa (only 1.5 times the Earth's atmosphere). Titan's atmosphere is very similar to Earth's. Its lower layers are also subdivided into troposphere and stratosphere. In the troposphere, the temperature drops with height, from -179 ° C at the surface to -203 ° C at an altitude of 35 km (on Earth, the troposphere ends at an altitude of 10-12 km). An extensive tropopause extends up to an altitude of 50 km, where the temperature remains almost constant. And then the temperature begins to rise, bypassing the stratosphere and mesosphere - about 150 km from the surface. AT ionosphere at an altitude of 400-500 km, the temperature rises to a maximum mark - approximately -120-130 ° C.

The air shell of Titan consists almost entirely of 98.4% nitrogen, the remaining 1.6% is methane and argon, which prevail mainly in the upper atmosphere. In this, too, the satellite is similar to our planet, since Titan and the Earth are the only bodies in the solar system, the atmospheres of which are mostly nitrogen (on the surface of the Earth, the concentration of nitrogen is 78.1%). Titanium does not have a significant magnetic field, so the upper layers of the air shell are highly susceptible to the solar wind and cosmic radiation. AT upper atmosphere, under the influence of ultraviolet solar radiation, methane and nitrogen form complex hydrocarbon compounds. Some of them contain at least 7 carbon atoms. If it goes down to surface of titan and look up, the sky will be orange, because the dense layers of the atmosphere are rather reluctant to let out the sun's rays. Organic compounds, including nitrogen atoms in the upper layers of the atmosphere, can also form such a color of the air.

Comparison of the Earth's atmosphere and the atmosphere of Titan. The air of both bodies is mostly

consists of nitrogen: Titanium - 94.8%, Earth - 78.1%. Moreover, in the middle layers

troposphere of Titan, at an altitude of 8-10 km contains about 40% of methane, which

under pressure, it condenses into methane clouds. Then to the surface

rains from liquid methane, as on Earth - water

An image of Titan from the Cassini spacecraft. Atmosphere satellite so

dense and opaque that it is impossible to see the surface from space

An interesting topic for discussion of Titan is undoubtedly satellite climate. The temperature at the surface of Titan averages -180 °C. Due to the dense and opaque atmosphere, the temperature difference between the poles and the equator is only 3 degrees. These low temperatures and high pressures counteract the melting of water ice, leaving the atmosphere virtually water-free. At the surface, the air almost entirely consists of nitrogen, and as it rises, the nitrogen concentration decreases, while the content of ethane C 2 H 6 and methane CH 4 increases. At an altitude of 8-16 km, the relative humidity of gases rises to 100% and condenses into discharged methane and ethane clouds. The pressure on Titan is sufficient to maintain these two elements not in a gaseous state, as on Earth, but in a liquid state. From time to time, when the clouds accumulate sufficient moisture, on the surface of Titan, like Earth sediment, fall ethano-methane rains and form entire rivers, seas, and even oceans from liquid "gas". In March 2007, during a close approach to the satellite, the Cassini apparatus discovered several giant lakes near the north pole, the largest of which reaches a length of 1000 km and is comparable in area to Caspian Sea. According to probe research and computer calculations, such lakes consist of carbon-hydrogen elements such as ethane C 2 H 6 -79%, methane CH 4 -10%, propane C 3 H 8 -7-8%, as well as a small amount of hydrogen cyanide 2-3% and about 1% butylene. Such lakes and seas, at terrestrial atmospheric pressure (100 kPa or 1 atm), would dissipate in a matter of seconds and turn into gas clouds. Some gases, such as propane and ethane, would remain at the bottom because they are heavier than air, while the methane would immediately rise up and dissipate into the atmosphere. On Titan, it's completely different. Low temperatures and pressure 1.5 times higher than the Earth's, maintain these substances in sufficient density for a liquid state. Scientists do not exclude the fact that life may well exist on the moon of Saturn in such seas and lakes. On Earth, life was formed due to the interaction and activity of liquid water, on titan instead of water, ethane and methane may well serve. It is clear that we are not talking about large and even small animals, but about microscopic, simple organisms. For example, bacteria that absorb molecular hydrogen and feed on acetylene and release methane in the process. How terrestrial animals inhale oxygen and exhale carbon dioxide.
Wind on the surface of the satellite, its speed is very weak, no more than 0.5 m / s, however, as it rises, it increases. Already at an altitude of 10-30 km, the winds blow at a speed of 30 m/s and their direction coincides with the direction of rotation of the satellite. At an altitude of 120 km from the surface, the wind turns into the most powerful whirlwind storms and hurricanes, the speed of which rises to 80-100 meters per second.

An artist's view of Titan's panorama. Methane lake surrounded by rocky

mountain structures has a dark yellow or light brown color and harmonizes beautifully

with an orange-tinted sky, like the blue sea - with the blue atmosphere of the Earth

The main elements in the circulation and interaction of the atmosphere are methane and ethane,
which can form in the bowels of Titan and be released into the air when
eruption of volcanoes. In the lower atmosphere, they condense into a liquid
and forms clouds, and then falls to the surface as methane and ethane rains

Surface and structure

The surface of Titan, like most of the satellites of Saturn, is divided into dark and light regions, which are separated from each other by clear boundaries. Like the Earth, the surface of the satellite is divided into land areas - continents and the liquid part - oceans and seas from liquid "gases" of methane and ethane. In the near equatorial region in the bright region is the largest continent of Titan - Xanadu. This is a huge mainland, the size of Australia, is a hill, consisting of mountain ranges. The mountain ranges of the mainland rise to a height of more than 1 km. On their slopes, like Earth streams, liquid rivers flow down, forming on flat surfaces methane lakes. Some of the more fragile rocks are subject to erosion, and from methane rains and streams flowing down the slopes of liquid methane, caves are gradually formed in the mountains. The dark region of Titan is formed due to the accumulation of particles of hydrocarbon dust falling from the upper atmosphere, washed off by methane rains from high places and brought to the equatorial regions by winds.

It is very difficult to say exactly what the internal structure of Titan is. Presumably located in the center hard core from stone rocks, 2/3 the size of the radius of Titan (about 1700 km). Above the nucleus is mantle consisting of both dense water ice and methane hydrate. Due to the tidal forces of Saturn and nearby satellites, the core of the satellite heats up, and the energy generated inside pushes hot rocks to the surface. In addition, as on Earth, radioactive decays of chemical elements occur in the bowels of Titan, which serves as additional energy for volcanic eruptions.

In April 1973, a NASA spacecraft was launched towards the Giant Planets. "Pioneer-11". Six months later, he made a gravitational maneuver around Jupiter and headed further towards Saturn. And in September 1979, the probe passed within 354,000 km of Titan's outer atmosphere. This convergence helped scientists determine that surface temperatures were too cold to support life. Years later Voyager 1 approached the satellite at 5600 km, took a lot of fairly high-quality pictures of the atmosphere, determined the mass and size of the satellite, as well as some orbital characteristics. In the 90s, using the powerful optics of the Hubble telescope, the atmosphere of Titan was studied in more detail - in particular methane clouds. Scientists have found that methane gas, like water vapor, is moistened in the upper layers and becomes a liquid. Then, in this form, it falls to the surface as precipitation.

The last and more significant stage in the study of Titan is considered the mission of the interplanetary space station " Cassini-Huygens". It made its first flyby of Titan on October 26, 2004, at a distance of only 1200 km from the surface. From this close range, the probe confirmed the presence of methane rivers and lakes. Two months later, on December 25, Huygens separated from the outer probe and began a four-hundred-kilometer dive through the opaque layers of Titan's atmosphere. The descent lasted 2 hours and 28 minutes. During this time, on-board instruments detected a dense methane haze (cloud layers) at an altitude of 18-19 km, where the atmospheric pressure was approximately 50 kPa (0.5 atm). The outside temperature at the beginning of the descent was -202°C, while on the surface of Titan it was about -180°C. To exclude impact collision with the surface of the satellite, the apparatus descended on a special parachute. The Space Flight Directorate, who watched Huygens sink, were very hopeful of seeing liquid methane on the surface. But the apparatus, contrary to wishes, plunged onto solid ground.

The project of the future called "Titan Saturn System Mission". This will be the first seafaring in history

outside the earth. The device will for 3 months surf the ocean expanses from liquid

methane and admire the sunset of the giant Saturn with its rings