Planetary scientists from the United States and Germany have studied the possible forms of extreme life that may be present on planets other than Earth and their satellites.
In particular, scientists admitted the existence of giant long-lived organisms on Titan. The authors published the research results in the journal Life, and a brief summary of them can be found on the website of the Washington State University.
Using the example of extreme organisms present on Earth, planetary scientists examined the possible physical and chemical features of the existence of extraterrestrial life forms. According to scientists, alien organisms, if they are real, may differ in a set of specific adaptations for survival in extreme (for most terrestrial organisms) conditions.
Huge alien creatures in the artist's fantasy
Planetary scientists have considered life forms that could be present on celestial bodies like Mars and Titan (the largest moon of Saturn). According to scientists, organisms on Mars may contain hydrogen peroxide as an intracellular fluid, and the life of creatures on Titan will be based almost exclusively on the chemistry of hydrocarbons.
The work of scientists, supported by the European Research Council, is motivated by the success of the Kepler telescope in searching for planets outside the solar system (exoplanets) and the need to assess the conditions in which the existence of life is permissible without contradicting the laws of physics and chemistry known to science.
"If you don't consider the various options for what life might be, you won't know what to look for and how to look," said study co-author Dirk Schulze-Makush of Washington State University.
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He added that scientists do not claim the existence of unusual organisms on Mars and Titan, but note that "their existence is consistent with physical and chemical laws, as well as biology."
For example, on Earth there are bombardier beetles that secrete a mixture of hydrogen peroxide and other compounds to repel predators. On Mars, according to Schulze-Makush, this would cause the insect to move 300 meters.
Hydrogen peroxide, which would be contained in the cells of Martian-like organisms, would help them survive in the cold conditions of a distant planet (would act as an antifreeze).
If organisms on the Red Planet can be similar to those on Earth, then the biochemistry of the creatures living on Titan should be, according to scientists, fundamentally different. The surface temperature on the moon of Saturn is minus 180 degrees Celsius, and there is almost no liquid water and carbon dioxide in its atmosphere and on its surface.
The role of liquid water on Titan is played by liquid methane and ethane. The moon of Saturn contains many reservoirs of these hydrocarbons. Titan is also prone to hydrocarbon deposits and seasonal changes. In this case, the role of the intracellular fluid in organisms living on objects like Titan can be played by solutions of hydrocarbons.
Fluid Hydrocarbon Channels on Titan
Cold (compared to terrestrial) conditions will lead to the fact that the metabolism of organisms on Titan will be very slow, and their cells will be extremely large. Aging of living beings under such conditions will occur much slower than that of the inhabitants of the Earth.
“Only the discovery of extraterrestrial life and the second biosphere will allow us to test these hypotheses,” said Schulze-Makush. This, he said, would be "one of the greatest achievements of our species."
Titan is the largest of Saturn's 62 moons. It is almost one and a half times the diameter of the Moon and almost twice the mass. Titan's atmosphere is dominated by nitrogen with methane impurities forming clouds. On January 14, 2005, the Huygens probe landed on the surface of the satellite, earlier (December 25, 2004) separated from the parent station Cassini.