Scientists found that Titan, Saturn's moon, is more similar to Earth than they ever expected. Data collated for seven years through NASA's Cassini probe yielded insight that enabled scientists to see Titan's atmospheric characteristics, solar magnetic field details and surface structure features that quite resemble Earth's.
Recently, researchers from the University College of London (UCL) reported that Titan also has polar winds similar to Earth's, which pull gases from the atmosphere toward outer space. Titan's atmosphere is composed of methane and nitrogen, exhibiting about 50 percent more pressure on its surface compared to the Earth, said Dr Andrew Coates of UCL's Mullard Space Science Laboratory.
During this study, the astronomers, who used the Cassini Plasma Spectrometer (Caps) partly developed by UCL, found that tons of hydrocarbons and nitriles are being lost each day in the atmosphere of Titan. However, the exact reason as to why this phenomenon occurs was not clearly identified at that time. It was later found that the mechanisms by which the solar magnetic field, the molecules in the upper atmosphere, and sunlight interact is responsible for the depletion of the gases.
Lakes and Seas
Another similarity that scientists have discovered between Earth and Titan has to do with bodies of water. Across the entire solar system, Earth and Titan are the only cosmic bodies that are known to have lakes and seas, as observed through the Cassini aircraft. In Titan, massive areas of seas that span hundreds of miles across the surface and several hundred feet in depth supply liquid to several "lakes" or other small channels. These lakes are filled by rainfall and subsequently dry up, as influenced by the seasonal cycle that occurs between Titan and Saturn for 30 years.
A new study published in the Journal of Geophysical Research further investigated the characteristics of these lakes. The scientists found that the manner by which these depressions are made is similar to the mechanisms that Earth's "karstic" landscapes are formed. This means that the areas of liquid pools in Titan are more likely sinkholes.
Earth also has sinkholes and these are formed when rainwater and groundwater permeating the ground erode soluble rocks, including gypsum and limestone. As time passes, secondary surfaces are formed, enabling the surface area to collapse into sinkholes. When vast bodies of water fill up rivers, these sinkholes are filled up as well, creating lakes.
Although the mechanisms involved in the formation of lakes are similar between Earth and Titan, the effects are not specifically the same. As Titan's environmental temperature is extremely low and seasons may run longer than Earth's, the time period necessary for these sinkholes to form in Titan is significantly longer than Earth. According to the researchers, it would take about 50 million years for a sinkhole measuring 100 meters to be formed in Titan. This is because of the high polar latitudes of the moon that is compatible with the young age of its surface.
"We compared the erosion rates of organics in liquid hydrocarbons on Titan with those of carbonate and evaporite minerals in liquid water on Earth," said Thomas Cornet of the European Space Agency, who is also the lead author of the research. "We found that the dissolution process occurs on Titan some 30 times slower than on Earth due to the longer length of Titan's year and the fact it only rains during Titan summer."
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