Except for nitrogen, which is the dominant component of the atmosphere, another gas of great importance is methane,
As noted in previous observations by the Chinese, on the ground of Titan there are features with the distinct shape of rivers, except that instead of water, liquid methane flows in them (the low temperatures of Titan make this possible). Several examples will be presented here.
1. Arcus Hotei bounded by mountain chains on the south and on the north by an extensive valley. From the peaks of the mountains descend several clear channels that are probably dry rivers that were cut by methane that flowed in them following rains in the valley. The rivers reach up to the formations of lobes (lobate) which are between 150-200 meters deep. Location 78 degrees West, 28 degrees South)
2. In the Southern Hemisphere at 240 degrees West, 71 degrees South, there is a complex system of canyons carved by a current of methane rivers. The flow was from high places to low places. The high explosiveness of tributaries shows that the rains have a very strong erosive capacity on the ground. The resulting impression is that Titan is geologically very active. It seems that the canyons were filled in the past by a fine granular material which appears dark in the radar images. This material was mined by a large river and rains (2).
3. In the North Pole, a river formation reminiscent of the Nile was found flowing in the direction of a great sea. Its length is 400 km. From this configuration there is a branching of tributaries (3).
A phenomenon reminiscent of a karst landscape was found on Titan. This is a phenomenon related to the melting of rocks following the penetration of water into them and is accompanied by depressions, valleys and underground caves. The karst landscape is found in humid or semi-humid climate zones. It is found in limestone and dolomite rocks. The place where karst formations were found on Titan is Sikun Labyrinthus (4).
atmosphere
Excluding nitrogen, which is the dominant component of the atmosphere, another gas of great importance is methane, methane molecules have a short lifespan because they are continuously broken down by sunlight and more complex molecules are formed in their place. To the same degree that heavy water exists, so does heavy methane. The distinction between light methane and heavy methane is in the carbon isotopes that make up the methane molecules. The normal carbon is carbon 12 and the heavy and also rare is carbon 13. Because of the low weight of the molecules containing carbon 12, their disintegration and transformation into more complex molecules is somewhat faster than carbon 13. Therefore the increase in the concentration of carbon 13 in the atmosphere is slower. Building models that examine the concentration of carbon 13 make it possible to check how long this chemical activity exists in Titan's atmosphere.
Based on one of the models, it was estimated that the age of the methane in Titan is 1.6 billion years, about 1/3 of Titan's age. The escape of methane from the layers of the upper atmosphere raises questions about this age. Other studies based on this fact significantly shorten the age of methane. The estimate according to these studies is that the age of methane is 10 million years. According to both models, the methane originates in Titan's interior and rises to the surface in one burst. As a result, heavy materials sank towards the center of the moon and light materials rose up towards the ground. For this reason its isotopes are always young. A process of this kind contradicts the assessment we referred to earlier.
A possible source of methane is Methane Clathrate - methane molecules trapped in a lattice of ice molecules. On Earth, the origin of the Methane Clathrate is in the depths of the crust of oceans. For this reason, there are those who think that beneath the surface of Titan there is an ocean of liquid water mixed with ammonia that acts as an anti freeze. If this hypothesis is correct, the methane reaches the ground through cryovolcanism or it erupts into the ground through cracks in the crust (5).
It turned out that the lower atmosphere is made of two layers that differ from the layers above them in their temperature. The thickness of the lower layer is 800 meters which changes on a daily basis (Titan's day). The thickness of the upper layer is 2 km and it changes with changes in the weather (6).
fog
The Hexini spacecraft detected the presence of fog along the South Pole. The fog, on the other hand, indicates the presence of liquid methane reservoirs on the surface of the moon that evaporate into the atmosphere. Evaporation seems to occur at the end of summer in large areas of the pole. The invention of the fog is in fact another evidence of a hydrological cycle of methane in the atmosphere. Fog on Earth can form when the humidity is at a rate of 100%. Evaporation can occur in several situations. One way is to add water to the air. The second and more common way occurs when the air cools in such a way that it cannot hold a larger amount of water and it undergoes a process of condensation (CONDENSE). As the sun rises the air warms and the fog dissipates. The formation of fog can also occur when cold air passes over cold ground. As the air cools, the water condenses (CONDENSE). Similarly, fog can form when moist air passes over mountains. It is pushed up the sides of mountains and causes the water to condense. None of these mechanisms exist on Titan. The reason for this is that the air takes a long time to cool down or warm up.. Even if the sun were to turn off completely, it would take 100 years for Titan's atmosphere to cool down completely. In addition, even the coldest parts of the ground are too hot to allow condensation. The only way for fog to form on Titan is the evaporation of liquid methane. There must be methane rain, methane flows from reservoirs, erosion and geology. The haze indicates that Titan has an active hydrological methane cycle.
The presence of the fog also indicates that there must be methane reservoirs. The reason for this is that all ground air, after the percentage of moisture in it reaches 100% and turns into fog, rises (the air) quickly into the atmosphere like a large cumulus cloud. The only way to make the fog stick to the ground is to add moisture and cool the air a little. Cooling the air to a small extent can be done by making contact with something cold such as a vaporized reservoir of liquid methane (7).
haze
In the photographs from - 22.5.2012 and from 7.6.2012 you see signs of the formation of haze over the South Pole. The haze is created hundreds of kilometers above the ground. When Cassini arrived at Saturn a haze was seen at the North Pole which was then in its winter season (8). Aerosols were also found at an altitude of 200 km above the pole. Since this phenomenon had not been observed before, it was clear that this was something new (9). Aerosols were first noticed in 2011 but nothing is yet known about their characteristics (10).
Sources for this part:
1. PIA11838: Rainy day at Hotei Arcus
http://photojournal.jpl.nasa.gov/catalog/PIA11838
2. PIA12036: Southern canyons of Titan
http://photojournal.jpl.nasa.gov/catalog/PIA12036
3. "Cassini spots mini Nile river on Saturn moon" 13.12.2012
http://www.spacedaily.com/reports/Cassini_Spots_Mini_Nile_River_On_Saturn _moon
4. "Is that Titan or Utah?" 8.4.2010
http://www.spacedaily.com/reports/Is_That_Titan_Or_Utah_999.html
5. Steigerwald B.-"NASA research estimates how long Titan's chemical factory has been in business" 27.4.2012/XNUMX/XNUMX
http://www.spacedaily.com/reports/NASA_Research_Estimates_How_Long_Titan’s _Chemical_ Factory_ Has_ Been _In _Business_999.html
6. Choi Charles Q. -"Saturn's moon Titan may be more Earth like than thought" 16.1.2012
http://www.space.com/14247-saturn-moon-titan-atmosphere-earth.html
7. "Scientists discover fog on Titan" 18.12.2009
http://www.physorg.com/news180350535.html
8. PIA15029: Winter's coming
http://photojournal.jpl.nasa.gov/catalog/PIA156029
9. "The Titanian seasons turn, turn, turn" 11.7.2012
http://www.spacedaily.com/reports/The_Titanian_Seasons_Turn_Turn_Turn_999.html
10. "Haze on Saturn's moon Titan may hold ingredients for life" 8.10.2010
http://www.sciencedaily.com/releases/2010/10/101008105847.htm
Titan (5) – climate, winds
Seasons
Since Titan, together with Saturn, orbits the Sun once every 29.5 years, each season on its surface lasts a little over 7 years. The Cassini research team began to notice significant seasonal changes between July 2004 (the beginning of summer in the Southern Hemisphere) and April 2010, the beginning of spring in the Northern Hemisphere (1). Its atmosphere reacts at a slow rate because the amount of light reaching it from the sun is one hundredth of that received by the Earth. The clouds move like those of the Earth, but more slowly (2). In 2011, meteorological activity was noticed in low latitudes and it was expected that these changes would move towards high latitudes (3).
For several years Cassini observed clouds in the mid-latitudes of the Southern Hemisphere. In the observations made in 2009 in the region of the equator at the equinox (the place where the sun is exactly above the equator of Saturn and its moons) a seasonal change moving towards the low latitudes was noticed (4)
Although Titan is colder than Earth, its climate pattern resembles that of a super hot Earth rather than a snowy Earth. The reason for this is that at the low temperatures of Titan, the methane is more volatile than water vapor at the temperatures of the Earth, this is the reason why the climate on Titan is defined as tropical. Apart from the presence of methane, what also contributes to this strange climatic behavior is the slow rotation of methane around itself (16 Earth days). The climate on Earth extends between latitudes 0 30 north and south and on Titan this climate covers the entire moon (2).
Spirits
Based on models that deal with the rotation of planets around themselves and the findings of the Huygens spaceship, it was estimated that the direction of movement of the terrestrial winds is east west. When the Cassini spacecraft began transmitting the first images of dunes to Israel in 2005, their orientation led to the opposite assessment that the winds move from west to east. The explanation given for this is that seasonal changes change the direction of the winds for a short time with the change of seasons. These wind gusts last two years in the west-east direction. The strength of the winds in this direction is so strong as to be able to move sand in a better way than in the normal east-west movement. The east-west oriented winds are not strong enough to transport significant amounts of sand (5).
In one of the observations, they noticed a particularly strong storm that looked like an arrow in the area of the equator. This storm had very strong effects such as creating dark-probably moist areas on the ground. With the disappearance of the storm, significant changes were seen on the ground along the southern boundary line of the Bellet dune field. These changes cover an area of half a million square kilometers (6) since Titan's atmosphere is denser than Earth's (1.6) and the moon's area is smaller, voice conductivity is stronger. One gets the impression that the storm was also accompanied by a thunder storm of a level of intensity far beyond what is known on earth (the hypothesis of the author of the life-writer Mazar).
In the photographs taken on June 27.6.2012, 2004, a concentration of haze was noticed at a very high altitude. And in the formation of a vortex at the South Pole, evidence that seasonal changes occur. A similar phenomenon was observed in the North Pole in 7 during its winter season. At that time the circulation of the upper atmosphere moves from the bright area of the North Pole towards the cooling South Pole. This movement causes the haze found in the heights and the eddies (XNUMX).
Sources
1. "Spring on Titan brings sunshine and patchy clouds" 23.9.2010
http://www.spacedaily.com/reports/Spring_On_Titan_Brings_Sunshine_And_ Patchy _Clouds_999.html
2. "Saturn's Titan-A unique world in the solar system-could life be Methane based?"
10.5.2011
http;//www.dailygalaxy.com/my_weblog/2011/05/Satun's-titan-a-unique-
world–in-the-solar-system-could–life-be-methane –based.html?utm_source=feedbu
3. Hetch J. – "Ethane lakes in red haze: Titan's uncanny moonscape" 11.7.2011
http;//www.newscientist.com/mg21128201.600-ethane-lakes-in-red-haze-titans uncanny- moonscape.html?/full=true
4. PIA12813: Titan's moving mid latitude clouds
http://photojournal.jpl.nasa.gov/catalog/PIA12813
5. "Cassini helps with dune whodunit" 30.7.2010
http://www.spacedaily.com/reports/Cassini_Helps_With_Dune_Whodunit_999.html
6. PIA12817: Titan's arrow shaped storm
http://photojournal.jpl.nasa.gov/catalog/PIA12817
7. "The Titanian seasons turn, turn, turn" 11.7.2012
http://www.spacedaily.com/reports/The_Titanian’s_Seasons_Turn_Turn_Turn_999.html
