For a long time it was believed that our blue planet is the only place in the solar system where there are conditions for the existence of life forms. In fact, it turns out that the near space is not so lifeless anymore. Today we can safely say that within the reach of earthlings there are worlds in many respects similar to our home planet. This is evidenced by interesting facts obtained as a result of studies of the vicinity of the gas giants Jupiter and Saturn. Of course, there are no rivers and lakes with clear and clean water, and grass does not grow green on the endless plains, but under certain conditions, humanity could take up their development. One such object in the solar system is Titan, the largest moon of Saturn.

Representation of the largest satellite of Saturn

Titan today worries and occupies the minds of the astronomical community, although more recently we looked at this celestial body, like other similar objects in the solar system, without much enthusiasm. It was only thanks to the flights of interplanetary space probes that it was discovered that liquid matter exists on this celestial body. It turns out that not far from us there is a world with seas and oceans, with a solid surface, shrouded in a dense atmosphere, very similar in structure to the earth's air shell. The size of Saturn's moon is also impressive. Its diameter is 5152 km, at 273 km. more than Mercury, the first planet in the solar system.

Previously, it was believed that the diameter of Titan is 5550 km. More accurate data on the size of the satellite have already been obtained in our time, thanks to the flights of the Voyager 1 spacecraft and the mission of the Cassini-Huygens probe. The first apparatus was able to detect a dense atmosphere on the satellite, and the Cassini expedition made it possible to measure the thickness of the air-gas shell, which is more than 400 km.

The mass of Titan is 1.3452 10²³ kg. According to this indicator, it is inferior to Mercury, as well as in density. The distant celestial body has a low density - only 1.8798 g / cm³. These data speak in favor of the fact that the structure of the satellite of Saturn differs significantly from the structure of the terrestrial planets, which are an order of magnitude more massive and heavier. In the Saturn system, this is the largest celestial body, the mass of which is 95% of the mass of the other 61 known moons of the gas giant.

Luckily and the location of the largest Titan. It runs in an orbit with a radius of 1,221,870 km at a speed of 5.57 km / s and stays outside the rings of Saturn. The orbit of this celestial body has an almost circular shape and is in the same plane as Saturn's equator. The orbital period of Titan around the parent planet is almost 16 days. Moreover, in this aspect, Titan is identical with our Moon, which rotates around its own axis synchronously with its owner. The satellite is always turned to the parent planet on one side. The orbital characteristics of the largest moon of Saturn ensure the change of seasons on it, however, due to the considerable remoteness of this system from the Sun, the seasons on Titan are quite long. The last summer season on Titan ended in 2009.

It is similar in size and mass to the other two largest moons in the solar system, Ganymede and Callisto. Such large sizes testify to the planetary theory of the origin of these celestial bodies. This is confirmed by the surface of the satellite, on which there are traces of active volcanic activity, which is a characteristic feature of the terrestrial planets.

For the first time, a photo of the surface of the satellite of Saturn was obtained using the Huygens probe, which safely landed on the surface of this celestial object on January 14, 2005. Even a cursory glance at the pictures gave every reason to believe that a new mysterious world was opening up before earthlings, living its own cosmic life. This is not the Moon, lifeless and deserted. This is the world of volcanoes and methane lakes. It is assumed that there is a vast ocean below the surface, possibly consisting of liquid ammonia or water.

Landing of the Huygens

The history of the discovery of Titan

For the first time, the existence of the satellites of Saturn was guessed by Galileo. Not having the technical ability to observe such distant objects, Galileo predicted their existence. Only Huygens, who already had a powerful telescope capable of magnifying objects 50 times, began to explore Saturn. It was he who managed to detect such a large celestial body revolving around a ringed gas giant. This event took place in 1655.

However, the name of the new celestial body had to wait. Initially, scientists agreed to give the discovered celestial body a name in honor of its discoverer. After the Italian Cassini discovered other satellites of the gas giant, they agreed to number the new celestial bodies of the Saturn system.

This idea was not continued, since other objects in the vicinity of Saturn were subsequently discovered.

The notation we use today was proposed by the Englishman John Herschel. They agreed that the largest satellites should have mythological names. Due to its size, Titan was the first on this list. The remaining seven large satellites of Saturn received names consonant with the names of the titans.

Atmosphere of Titan and its features

Among the celestial bodies of the solar system, Titan has perhaps the most curious air shell. The atmosphere of the satellite turned out to be in fact a dense layer of clouds, which for a long time prevented visual access to the very surface of the celestial body. The density of the air-gas layer is so high that at the surface of Titan the atmospheric pressure is 1.6 times higher than the terrestrial parameters. Compared to the Earth's air shell, the atmosphere on Titan has a significant thickness.

The main component of the titanium atmosphere is nitrogen, the share of which is 98.4%. Approximately 1.6% are argon and methane, which are mainly located in the upper layers of the air shell. With the help of space probes, other gaseous compounds were also found in the atmosphere:

• acetylene;
• methylacetylene;
• diacetylene;
• ethane;
• propane;
• carbon dioxide.

Small amounts of cyanide, helium and carbon monoxide are present. No free oxygen has been found in Titan's atmosphere.

Despite such a high density of the air-gas shell of the satellite, the absence of a strong magnetic field affects the state of the surface layers of the atmosphere. The upper atmosphere is exposed to the solar wind and cosmic radiation. Nitrogen (N) under the influence of these factors reacts, forming a number of curious nitrogen-containing compounds. Most of some of the compounds are deposited on the surface of the satellite, giving it a slightly orange tint. The history of methane is also interesting. Its composition in Titan's atmosphere is stable, although due to external influences, this light gas could have evaporated long ago.

Looking at the satellite's atmosphere in layers, one can notice a curious detail. The air shell on Titan is stretched in height and is clearly divided into two layers - near-surface and high-altitude. The troposphere begins at an altitude of 35 km. and ends with the tropopause at altitudes of 50 km. Here there are stably low temperatures of -170⁰ C. Further, with height, the temperature drops to -120 degrees Celsius. Titan's ionosphere begins at an altitude of 1000-1200 km.

It is assumed that this composition of the atmosphere of Titan is due to its active volcanic past. The air layers saturated with ammonia vapor decomposed into nitrogen and hydrogen under the influence of cosmic ultraviolet, and other components are the result of physicochemical reactions. As heavier, nitrogen sank and became the main component of the titanium atmosphere. Hydrogen, due to the weak gravitational forces of the satellite, escaped into outer space.

The layers of Titan's atmosphere, the interaction of its chemical composition with the magnetic field of a celestial body contribute to the fact that the satellite has its own climate. The seasons on Titan change like Earth's seasons. At a time when one side of the satellite is facing the Sun, Titan is plunging into summer. Storms and hurricanes rage in its atmosphere. The air layers heated by sunlight are in constant convection, generating strong winds and significant movements of cloud masses. At altitudes of 30 km, the wind speed reaches 30 m/s. The higher, the more intense and powerful the turbulence of air masses. Unlike Earth, the cloud masses on Titan are concentrated in the polar regions.

The concentration of methane in the upper atmosphere explains the increase in temperature on the surface of the satellite due to the greenhouse effect. However, the presence of organic molecules in the composition of air masses allows ultraviolet to freely penetrate in both directions, cooling the surface layer of the titanium crust. The surface temperature is -180⁰С. The difference between the temperatures at the poles and at the equator is negligible - only 3 degrees.

High pressure and low temperatures contribute to the fact that water molecules in the atmosphere of the satellite completely evaporate (freeze).

The structure of the satellite: from the outer shell to the core

The assumption and conjectures about the structure of such a large celestial body were mainly based on the data of terrestrial optical observations. The dense atmosphere of Titan inclined scientists towards the hypothesis of the gas composition of the satellite, akin to the composition of the mother planet. However, after the flights of the Pioneer 11 and Voyager 2 space probes, it became clear that we are dealing with a celestial body whose structure is solid and stable.

Today, Titan is believed to have a crust similar to Earth's. The diameter of the core is approximately 3400 km, which is more than half the diameter of the celestial body. Between the core and the crust there is an ice layer, which differs in its composition. Probably, at certain depths, the ice transforms into a liquid structure. Comparison of images taken from the Cassini AMS with a difference of two years indicated the presence of a displacement of the surface layer of the satellite. This information gave scientists a reason to believe that the surface of the satellite rests on a liquid layer, which consists of water and dissolved ammonia. The displacement of the crust is caused by the interaction of gravitational forces and the circulation of the atmosphere.

In its composition, Titan is a combination of ice and silicate rocks in equal proportions, which is very similar to the internal structure of Ganymede and Triton. However, due to the presence of a dense air shell, the structure of the satellite has its own differences and specifics.

The main features of a distant satellite

The mere presence of an atmosphere on Titan makes it unique and interesting for further study. Another thing is that the main highlight of the distant satellite of Saturn is the presence of large volumes of liquid on it. This failed planet is characterized by lakes and seas, in which waves of methane and ethane splash instead of water. The satellite has accumulations of cosmic ice on the surface, which owes its origin to water and ammonia.

Evidence of the existence of liquid matter on the surface of Titan came from photographs of a huge basin larger than the Caspian Sea in area. The huge sea of ​​liquid hydrocarbons is called the Kraken Sea. According to its composition, it is a huge natural reservoir of liquefied gases: ethane, propane and methane. Another large accumulation of fluid on Titan is the Ligeia Sea. Most of the lakes are concentrated in the northern hemisphere of Titan, which greatly increases the reflectivity of a distant celestial body. After the Cassini mission, it became clear that the surface is 30-40% covered with liquid matter collected in natural seas and lakes.

Such a huge amount of methane and ethane, which are in a frozen state, contributes to the development of certain forms of life. No, these will not be habitual terrestrial organisms, however, under such conditions, living organisms on Titan can take place. There are enough components and chemicals on the satellite for the formation of organisms and their subsequent existence.

Timeline of modern Titan exploration

It all started with the modest mission of the American Pioneer 11 probe, which in 1979 managed to give scientists the first pictures of a distant satellite. For a long time, the information received from the Pioneer was of little interest to astrophysicists. Progress in studying the vicinity of Saturn came after Voyager visits to this region of the solar system, which gave more detailed images of the satellite, taken from a distance of 5000 km. Scientists have received more accurate data on the size of this giant, the version about the existence of a dense atmosphere of the satellite has been confirmed.

Flight of the Pioneer

Infrared images taken from the Hubble Space Telescope have provided scientists with information about the composition of the moon's atmosphere. For the first time, light and dark regions were identified on the planetary disk, the nature of which remained unknown. For the first time, a theory was born that the surface of Titan is covered in some places with ice, which increases the reflectivity of the celestial body.

Success in the field of research came along with information received from the Cassini automatic interplanetary station. Launched in 1997, the Cassini mission is a common ESA development at NASA. Saturn became the main focus of research, but its satellites were not left without attention. So, to study Titan, the flight program included the stage of landing on the surface of Saturn's satellite of the Huygens probe. This device, created by the efforts of NASA and the Italian space agency, whose team decided to mark the anniversary of their glorious compatriot Giovanni Cassini, was supposed to descend to the surface of Titan.

Cassini orbiting Saturn

For 4 years, Cassini continued to work in the vicinity of Saturn. During this time, AMS flew twenty times near Titan, constantly receiving new data about the satellite and its behavior. Already one landing of the Huygens probe on Titan, which took place on March 14, 2007, is considered a tremendous success for the entire mission. Despite this, given the technical capabilities of the Cassini station and its great potential, it was decided to continue research on Saturn and its satellites until 2017.

The flight of Cassini and the landing of the Huygens spacecraft provided scientists with comprehensive information about what Titan really is. Photographs and video filming of the surface of Saturn's moon have shown that the upper layers of the crust are a mixture of mud and gaseous ice. The main fragments of the soil are stones and pebbles. Titan's landscape is an alternation of solid, elevated areas with lowlands. During the landing, pictures of the landscape were taken, which clearly marked the riverbeds and coastline.

Photo of Titan from the Huygens

Titan today and tomorrow

How the further study of the largest satellite will end is unknown. It is assumed that the conditions created in terrestrial laboratories, similar to those that exist on Titan, will shed light on the version of the possibility of the existence of life forms. Flights of space probes into this region of space are not yet planned. The information obtained is sufficient to model Titan under terrestrial conditions. How useful these studies will be, only time will tell. It remains only to wait and hope that Titan will reveal its secrets in the future, giving hope for its development.

Titanium- the largest satellite of Saturn and the second largest solar system: photo, size, mass, atmosphere, name, methane lakes, Cassini research.

The Titans ruled the Earth and became the progenitors of the Olympic gods. That is why the largest satellite of Saturn was named Titan. It occupies the 2nd place in size in the system and exceeds Mercury in volume.

Titan is the only satellite of Saturn endowed with a dense atmospheric layer, which for a long time prevented the study of surface features. Now we have evidence of the presence of liquid on the surface.

Discovery and name of the satellite Titan

In 1655, Christian Huygens noticed a satellite. This discovery was inspired by Galileo's findings near Jupiter. Therefore, in the 1650s. he began to develop his telescope. At first it was simply called the Moon of Saturn. But later, Giovanni Cassini will find 4 more, so he was called by position - Saturn IV.

The modern name came from John Herschel in 1847. In 1907, Josell Comas Sola tracked the darkening of Titan. This is the effect where the center of a planet or star appears much brighter than the edge. This was the first signal to detect the atmosphere on the satellite. In 1944, Gerard Kuiper used a spectroscopic instrument and found a methane atmosphere.

Size, mass and orbit of the Titan satellite

The radius is 2576 km (0.404 Earth), and the mass of the Titan satellite is 1.345 x 10 23 kg (0.0255 Earth). The average distance is 1,221,870 km. But an eccentricity of 0.0288 and an inclination of the orbital plane of 0.378 degrees caused the satellite to approach 1,186,680 km and move away 1,257,060 km. Above is a photo comparing the size of Titan, the Earth and the Moon.

Thus, you learned which planet Titan is a satellite of.

Titan spends 15 days and 22 hours on an orbital flyby. The orbital and axial periods are synchronous, therefore it stays in the gravitational block (turned to the planet by one side).

The composition and surface of the moon Titan

Titanium is denser due to gravitational contraction. Its index of 1.88 g/cm 3 hints at an equal ratio of water ice and rocky material. Inside it is divided into layers with a rocky core covering 3400 km. A 2005 Cassini study hinted at the possible presence of an underground ocean.

It is believed that Titan's liquid consists of water and ammonia, which makes it possible to fix the liquid state even at a temperature mark of -97 ° C.

The surface layer is considered to be relatively young (from 100 million to 1 billion years) and looks smooth with impact craters. The height varies by 150 m, but can reach 1 km. It is believed that this was influenced by geological processes. For example, on the southern side, a mountain range was formed with a length of 150 km, a width of 30 km and a height of 1.5 km. Filled with icy material and a layer of methane snow.

Patera Sotra is a mountain range that stretches to a height of 1000-1500 m. Some peaks are endowed with craters and it seems that frozen lava flows have accumulated at the base. If there are active volcanoes on Titan, then they are provoked by energy coming from radioactive decay.

Some believe that this is a geologically dead place, and the surface was created due to crater impacts, fluid flows and wind erosion. Then methane does not come from volcanoes, but is released from the cold lunar interior.

Among the craters of Titan's moon, the 440-km two-zone Minerva impact basin stands out. It is easy to find by its dark pattern. There are also Sinlap (60 km) and Xa (30 km). Radar survey was able to find crater forms. Among them is the 90-kilometer ring of Guabonito.

Scientists have theorized about the presence of cryovolcanoes, but so far only surface structures with a length of 200 m that look like lava flows have hinted at this.

Channels may hint at tectonic activity, which means that we have young formations in front of us. Or is it an old place. You can find dark areas that are patches of water ice and organic compounds showing up in the UV view.

Methane lakes of the moon Titan

Saturn's moon Titan attracts attention with its hydrocarbon seas, methane lakes and other hydrocarbon compounds. Many of them are noted near the polar regions. One covers an area of ​​15,000 km 2, and a depth of 7 m.

But the largest is the Kraken at the North Pole. The area is 400,000 km 2 and the depth is 160 m. We even managed to note small capillary waves with a height of 1.5 cm and a speed of 0.7 m/s.

There is also the Sea of ​​Ligeia, located closer to the north pole. The area covers 126,000 km 2. It was here in 2013 that NASA first noticed the mysterious object - Magic Island. Later it will disappear, and in 2014 it will reappear in a different form. This is thought to be a seasonal feature created by rising bubbles.

Mostly lakes are concentrated near the poles, but similar formations have also been found on the equatorial line. In general, the analysis shows that the lakes cover only a few percent of the surface, which is why Titan is much drier than our planet Earth.

Titan's atmosphere

Titan is so far the only satellite in the solar system that has a dense atmosphere with a remarkable amount of nitrogen. Moreover, it even exceeds the earth's density with a pressure of 1.469 kPa.

Represented by an opaque haze that blocks incoming sunlight (reminiscent of Venus). Lunar gravity is low, so the atmosphere is much larger than Earth's. The stratosphere is filled with nitrogen (98.4%), methane (1.6%) and hydrogen (0.1%-0.2%).

Titan's atmosphere contains traces of hydrocarbons such as ethane, acetylene, diacetylene, propane, and methylacetylene. It is believed that they form in the upper layers due to the breakdown of methane by UV rays, which creates a thick orange-colored smog.

The surface temperature reaches -179.2°C because, compared to us, the moon receives only 1% of the sun's heat. In this case, the ice is endowed with low pressure. If not for the greenhouse effect from methane, then Titan would be much cooler.

Fog that reflects sunlight works against the greenhouse effect. Simulations have shown that complex organic molecules can appear on the satellite.

Hot planetary coronas

Astronomer Valery Shematovich on the study of gas shells of planets, hot particles in the atmosphere and discoveries on Titan:

The habitability of the Titan satellite

Titan is perceived as a probiotic environment with complex organic chemistry and a possible subsurface ocean in a liquid state. Models show that the addition of UV rays in such an environment can lead to the formation of complex molecules and substances, such as tholins. And the addition of energy causes even 5 nucleotide bases.

Many believe that the satellite contains enough organic material to activate the process of chemical evolution similar to that of the Earth. This requires water, but life could survive in the subsurface ocean. That is, life can appear on Saturn's moon Titan.

Such forms must be able to survive in extreme conditions. It all depends on the heat exchange between the inner and upper layers. Do not exclude the presence of life in methane lakes.

To test the hypothesis, several models were created. Atmospheric shows that there is a large amount of molecular hydrogen in the upper layer, which disappears closer to the surface. Low levels of acylene are also indicative of hydrocarbon consuming organisms.

In 2015, researchers even created a cell membrane capable of functioning in liquid methane under specified lunar conditions. But at NASA, these experiments are considered hypotheses and rely more on the levels of acylene and hydrogen.

In addition, the experiments still concerned earthly ideas about life, and Titan is different. The satellite lives much further from the Sun, and the atmosphere is devoid of carbon monoxide, which does not allow it to retain the necessary amount of heat.

Exploration of the Titan satellite

The rings of Saturn often overlap the moon, so without special tools, Titan is difficult to find. But then there is a barrier from a dense atmospheric layer, which makes it difficult to see the surface.

For the first time, Pioneer 11 approached Titan in 1979, presenting images. He noted that the moon is too cold to support life forms. Voyagers 1 (1980) and 2 (1981) followed, providing data on density, composition, temperature and mass.

The main information array came from the study of the Cassini-Huygens mission, which arrived at the system in 2004. The probe captured surface details and color patches that were previously inaccessible to human vision. He also noticed the seas and lakes.

In 2005, the Huizens probe descended to the surface, capturing surface formations up close.

He also obtained images of a dark plain that hinted at erosion. The surface was much darker than scientists expected.

In recent years, more and more questions have been raised about returning to Titan. In 2009, they tried to push the TSSM project, but it was bypassed by EJSM (NASA / ESA), whose probes will go to Ganymede and Europa.

TiME was also planned, but NASA decided that it would be more expedient and cheaper to launch InSight to Mars in 2016.

In 2010, they considered the possibility of launching JET - an astrobiological orbiter. And in 2015, they came to the development of a submarine that can dive into the Kraken Sea. But for now, it's all under discussion.

Titan moon colonization

Of all the satellites, Titan seems to be the most profitable target for a colony.

Titanium has a huge number of elements that are needed to sustain life: methane, nitrogen, water and ammonia. They can be transformed into oxygen and even create an atmosphere. The pressure is 1.5 times higher than the Earth's, and the dense atmosphere protects much better from cosmic rays. Of course, it is filled with flammable substances, but an explosion requires a huge amount of oxygen.

But there is also a problem. Gravity is inferior to the indicators of the earth's moon, which means that the human body will have to fight against muscle atrophy and bone destruction.

It is not easy to cope with frost at -179 ° C. But the satellite is a tasty morsel for explorers. There is a high probability of coming across life forms that can survive in extreme conditions. Perhaps we will also come to colonization, because the satellite will become the starting point for the study of more distant objects and even exit from the system. Below is a map of Titan and high-quality high-resolution photos from space.

Titan surface map

Click on the image to enlarge it

Photos of the satellite Titan

The Cassini spacecraft approached within 2 million km on May 29, 2017 to capture the night side of Titan in a photo. This review succeeded in emphasizing the extended atmospheric nebula of the moon. For the entire time of observation, the device managed to fix the satellite from various angles and get a full view of the atmosphere. The high-altitude fog layer is displayed in blue, and the main haze is orange. The difference in color may be based on particle size. Blue, most likely, is represented by small elements. A narrow-angle camera with red, green and blue filters was used for shooting. The scale is 9 km per pixel. The Cassini program is a joint development of ESA, NASA and the Italian Space Agency. The team is based in JPL. The two cameras on board are also made by them. The obtained photos are processed in Boulder (Colorado).

Let's start with the rain. It has been established that the clouds on Titan consist of organic compounds - bicarbonates, represented mainly by methane and, to a lesser extent, ethane. Small amounts of propane, ammonia**, acetylene, and also water ice. Clouds are sources of methane and ethane rain**. The greatest amount of clouds is concentrated in the northern and southern polar regions of Titan. In the north, this is generally a zone of continuous cloudiness, which covers Titan with a "blanket" up to 62 ° C.L.

In addition, scientists have obtained evidence of the existence of "underground" reservoirs of methane, ethane and propane, which find their way to the surface in the form of geysers and feed the rivers. The rivers and seas on Titan also consist ofmethane and ethane.
Thus, the circulation of substances constantly takes place on Titan: the eruption of gas and liquid from the bowels, the precipitation in the form of rain or snow, the deposition of matter and evaporation. This process is similar to that which takes place on Earth, only on our planet water is involved in the cycle, and on Titan - hydrocarbons. Is it true, Water has also been found on Titan, and in large quantities. - in the form of deposits of water ice and flows of the so-called "cryovolcanic" superheated ice or a mixture of liquid water and ammonia. According to scientists from the University of Arizona and the University of Nantes, under the surface of Titan there may be an ocean of liquid water with ammonia dissolved in it.
E Another feature of the surface of Titan, bringing it closer to the Earth, are extended lines and linear zones that delimit areas with different types of relief, which often intersect with each other.
According to experts, they are faults in the crust of this planet, which consists of a mixture of water and hydrocarbonate ice. In addition, a structure was found on the surface of Titan that is very similar to a volcano with a diameter of 30 km with lava flows flowing down from it - ice or a mixture of liquid water and ammonia, a volcanic caldera with a diameter of 180 km, volcanic calderas20-30 km in diameter and lava flows from ice or a mixture of liquid water and ammonia over 200 km long.
Thus the Titanit is an active planet in all respects , which is characterized by:
- circulation of the atmosphere, manifested in the formation and transport of clouds, precipitation (rain and possibly snow) and weather changes;
- endogenous (deep) activity, manifested in the formation of faults and cryolitic volcanism,
- exogenous (surface) activity, manifested in the weathering of rocks and the deposition of sediments.
At present, the three listed types of activity have been observed simultaneously only on Earth and Titan.

As on other planets of the solar system, several (certainly two - Xa and Sinlap) meteorite craters with a diameter of 40 to 80 km and one giant ring structure with a diameter of about 450 km, called the circus Maximum or Mernvoy, were found on Titan. It, apparently, is an ancient meteorite crater - a water basin limited by ring-shaped mountain ranges, which was formed during a collision with Titan of an asteroid or comet tens of kilometers in size. A small number of meteorite craters encountered on the surface of Titan testify to the young age of its surface, which continues to form at the present time.

Are Titans inhabited?

At first glance, it may seem that temperatures below -180 ° C prevailing on the surface of Titan do not even allow one to think about life on this planet. But this is in the opinion of earthlings, accustomed to living in more comfortable, from their point of view, conditions. "No, life is impossible in this cold," 99.9% of us would probably say.
But is it? After all, nothing happens by chance in nature. In any habitable world, rains are likely to water the land and fill the rivers; rivers, lakes and seas - serve as a source of fluid and habitat for organisms leading a marine lifestyle. Plains and mountains should be the habitat of various land organisms.
It is known that all living things on Earth are mainly composed of water. The water content in different organisms varies between 50-75% (terrestrial plants), 60-65% (terrestrial vertebrates), 80-99% (fish and marine animals and plants). But what if the inhabitants of Titan, if they, of course, exist, are also 50 or 99% liquid methane or ethane, and the remaining 50 or 1% of some material that can withstand such low temperatures? Whether they in this case have a solid skeleton, for example, made of silicon, or whether they are gel-like creatures like jellyfish (by the way, jellyfish on Earth use nitrogen as food) is unknown. Be that as it may, there is more than enough organic matter to build organisms and food for them on Titan. This means that the prerequisites for the development of life exist. But what about life itself?
One thing is clear: if there is life on Titan, it is undoubtedly other life that will be difficult to contact.

I express my sincere gratitude to NASA (NASA) and ECA (ECA) for the opportunity to use the photos

The hypothesis about the possibility of the existence of life on Titan is confirmed in the works of many scientists. Christopher McKay of NASA Ames Research Center, Heather Smitha of the International Space University in Strasbourg, Dirk Schulze-Makuha of Washington State University, David Grinspoon of the Denver Museum of Natural History and several other researchers believe that such a large amount of methane in the atmosphere of Titan is not accidental. In fact, the sun's rays reaching the surface of the planet must destroy methane molecules, and without its constant replenishment, all atmospheric methane available on Titan would have to be destroyed in 10-20 million years. Suggested sources of this gas may be the volcanic activity occurring on Titan and the life that exists there. The possibility of the existence of life on Titan seems to be confirmed by a decrease in the content of hydrogen in the lower part of its atmosphere. According to Christopher McKay, this is due to the fact that it is consumed by living organisms.

Almost 5 years after this article was written, new data have been obtained that convincingly prove the existence of life on Titan. Read about it in the news

Read also my new job"Life on Titan. What is she?"

I invite everyone to further discuss this material on the pages

The second largest in the solar system after Ganymede (Jupiter). In its structure, this body is very similar to the Earth. Its atmosphere is also similar to ours, and in 2008 a large underground ocean was discovered on Titan. For this reason, many scientists suggest that this particular satellite of Saturn will become the abode of mankind in the future.

Titan is a moon that has a mass equal to about 95 percent of the mass of all Saturns. The force of gravity is about a seventh of that on Earth. It is the only satellite in our system that has a dense atmosphere. The study of the surface of Titan is difficult due to the thick cloud layer. The temperature is minus 170-180 degrees, and the pressure at the surface is 1.5 times higher than that of the Earth.

There are lakes, rivers and seas of ethane and methane on Titan, as well as high mountains, which are composed mainly of ice. According to the assumptions of some scientists, around the stone core, which reaches a diameter of 3400 kilometers, there are several layers of ice with different types of crystallization, and also, possibly, one layer of liquid.

In the course of research on Titan, a huge hydrocarbon pool was discovered - the Kraken Sea. Its area is 400,050 square kilometers. According to computer calculations and photographs taken from the spacecraft, the composition of the liquid in all lakes is approximately the following: ethane (about 79%), propane (7-8%), methane (5-10%), hydrogen cyanide (2-3%) , acetylene, butane, butene (about 1%). According to other theories, the main substances are methane and ethane.

Titan is a moon whose atmosphere is about 400 kilometers thick. It contains layers of hydrocarbon smog. For this reason, the surface of this celestial body cannot be observed with a telescope.

The planet Titan receives very little solar energy to ensure the dynamics of processes in the atmosphere. Scientists have suggested that the energy to move atmospheric masses provides a strong tidal effect of the planet Saturn.

Rotation and orbit

The radius of Titan's orbit is 1,221,870 kilometers. Outside of it, there are such satellites of Saturn as Hyperion and Iapetus, and inside - Mimas, Tethys, Dione, Enceladus. Titan's orbit passes out

The Titan satellite makes a complete revolution around its planet in fifteen days, twenty-two hours and forty-one minutes. The orbital speed is 5.57 kilometers per second.

Like many others, the Titan satellite rotates synchronously with respect to Saturn. This means that the time of its rotation around the planet and around its axis coincide, as a result of which Titan always turns one side to Saturn, so there is a point on the surface of the satellite at which Saturn always appears to be hanging at the zenith.

The tilt of the axis of rotation of Saturn provides on the planet itself and its satellites. For example, the last summer on Titan ended in 2009. At the same time, the duration of each season is approximately seven and a half years, since the planet Saturn makes a complete revolution around the Sun star in thirty years.

Titan is the largest satellite of Saturn (diameter - 5150 km) and the only satellite of the solar system with a dense atmosphere through which it is impossible to observe the surface of this satellite. The pressure near the surface is about 1.6 times the pressure of the earth's atmosphere. Temperature - minus 170-180 ° C. Titan is larger than the planet Mercury, although it is inferior to it in mass. The force of gravity on it is approximately one-seventh of the earth's.

The main information about this mysterious satellite was obtained quite recently using the Huygens spacecraft, which entered the dense atmosphere of Titan and sat on its surface in 2005.

Structure

Titan has a composition about the same as most satellites of the giant planets - about half the ice and the same amount of rocks. Probably a stone core with a diameter of 3400 km, on top of which several layers of ice of various degrees of crystallization were formed. Half of the rock mass contains potassium. It is assumed that there may be methane springs on the surface, in which methane rivers originate. Scientists suggest that the methane reserves on the surface of Titan must be constantly renewed from some unknown source inside Saturn's moon, i.e. Methane is constantly being destroyed by photochemical processes in the upper atmosphere. That. its current amount will disappear in 20 million years. If the methane seen today is only a remnant of a much larger amount of this gas that has by now almost disappeared, the ratio of carbon isotopes in CH4 molecules should be close to what is measured for nitrogen and oxygen (on Earth). Since this is not observed, methane must be constantly renewed. One of the sources of methane can be volcanic activity.

Atmosphere

As already mentioned, Titan has a dense atmosphere, several hundred kilometers thick. It is 95% nitrogen. Thus, Titan and the Earth are the only bodies in the solar system that have a dense atmosphere with a predominant nitrogen content. The remaining 5% is predominantly methane, there are also traces of ethane, diacetylene, methylacetylene, cyanoacetylene, acetylene, propane, carbon dioxide, carbon monoxide, cyanogen, and helium.

On Titan, methane must perform the same function as water on earth, and go through the cycle - precipitation, collection on the surface, evaporation, condensation, precipitation.

In the upper atmosphere, under the influence of ultraviolet solar radiation, methane and nitrogen decompose and form complex hydrocarbon compounds. Some of them, according to the Cassini mass spectrometer, contain at least 7 carbon atoms. Nitriles, a kind of amino acid precursors, have been identified among nitrogen compounds.

During the descent, the Huygens probe detected wind at altitudes from 9.6 to 19.2 kilometers. The wind speed was 25.6 kilometers per hour.

The spacecraft's instruments detected a thick hazy (or cloudy) layer of methane at altitudes of 17.6-19.2 kilometers, where atmospheric pressure was approximately 0.5 atmospheres. There was also methane fog below.

The temperature of the atmosphere (in the initial phase of the descent) was 70.5 degrees Kelvin (minus 202.6 Celsius), while on the surface of the planet the "air" was slightly warmer: 93.8 degrees Kelvin (minus 179.3 degrees Celsius). Celsius).

Scientists were especially interested in the mystery of ethane clouds, which turned out to be much smaller over Titan than theoretical models predicted. The fact is that solar ultraviolet constantly destroys methane molecules, which the atmosphere of Saturn's satellite is very rich in, and one of the by-products of such a reaction is ethane.

Now, planetary scientists from Arizona have made clearer how ethane cycles on this amazing planet and helped to understand where it disappears.

In the area of ​​the northern polar circle of Titan, between the 51st and 69th degrees of latitude, at an altitude of 30-60 kilometers, Cassini instruments captured large ethane clouds. Observations show that surface deposits of ethane should be located precisely in the polar regions, and not be distributed globally, as previously assumed. This may partly explain the lack of ethane oceans and ethane clouds at Titan's low latitudes. It is possible that right now at the planet's north pole, ethane is being released as rain or, if the temperature is low enough, as snow. And when the new season begins, ethane will fall at the south pole.

According to scientists, ethane should accumulate at the poles like polar ice. Ethane also dissolves in methane, which, as you know, consists of the local rains. Scientists suggest that during the polar winter, methane lakes form in the lowlands, which are also rich in ethane. Perhaps these are the same lakes that Cassini recently discovered.

If ethane had been produced in Titan's atmosphere at the present rate for the lifetime of the planet, ethane ice caps two kilometers thick would have formed at the poles. So far, scientists have no direct evidence of the existence of polar caps on this planet at all.

Nevertheless, at the South Pole, for example, instruments recorded something like rivers, perhaps originating in the local semblance of glaciers. One way or another, in the coming months, the American apparatus will perform a series of flights over the poles of this amazing planet, and more information will be added for analysis.

Surface

The surface of Titan is relatively flat; altimetry showed height differences of no more than 100 m over several hundred kilometers. At the same time, local elevation differences, as shown by the radar data and stereo images obtained by Huygens, can be quite significant; steep slopes on Titan are not uncommon. This is the result of intense erosion with the participation of wind and liquid. There are several objects that look like impact craters, filled presumably with hydrocarbons.

Dark and light areas on the surface were also found. One of these bright areas has a shape similar to Australia. Scientists suggest that this is a continent called Xanadu (Xanadu). At the western edge of the captured area, dark dunes give way to a complex landscape cut by branching river networks, hills and valleys. These narrow river networks flow to darker areas that may be lakes. A crater was also found here, formed either by an asteroid impact or by water volcanism.

The meandering channels of eastern Xanadu end in a dark plain where the dunes (which are found in abundance elsewhere) seem to be absent.

Finally, all this magnificence of various landscapes is crowned by mountains the size of the Appalachians, which cross the considered region of the gas giant's satellite.

There are also dark regions of similar size, encircling the satellite along the equator, which were initially identified as methane seas. Radar studies, however, have shown that the dark equatorial regions are universally covered with long parallel rows of dunes, elongated in the direction of the prevailing winds (from west to east) - the so-called. "cat scratches" Only in some places are fixed areas of a flat (possibly liquid) surface, corresponding in area to lakes rather than seas. The dark color of the lowlands is explained by the accumulation of hydrocarbon “dust” particles that fall from the upper layers of the atmosphere and are washed away by methane showers from the uplands.

In June 2005, Cassini discovered a much darker, very well-defined feature located in a region with very powerful (possibly "shower") clouds that could be identified as a true liquid lake. It is similar in size and shape to Lake Ontario, hence the name Lacus Ontario. It is not yet clear whether there is liquid there, or a dark dried bottom covered with a sedimentary layer. According to some indications, the active "work" of hydrocarbon liquids on the surface of Titan (rain or springs, streams and rivers beating from under the surface) is seasonal. Further study of the lake should reveal its mystery.

Already in July 2006, Cassini discovered a dozen lakes up to 110 kilometers in size. Some of them are interconnected by canals, while others, separate ones, are replenished by rivers. Several of them turned out to be dry (as scientists had previously thought), but some were filled with a liquid, apparently a mixture of methane and ethane.

Some lakes probably do not always remain dry, but periodically fill up during hydrocarbon rains. However, new data have not yet been able to confidently answer the question - what is the source of these substances.