Whether life can exist outside of Earth is one of the controversial topics among many scientists as well as common people. Space research institutes in many countries are working rapidly to get a clue about extraterrestrial life. From listening to extraterrestrial radio signals with the help of giant radio telescopes to having golden disks containing information related to Earth in the Voyager spacecraft sent out of the solar system, attempts to communicate with extraterrestrial civilizations can be called.
The optimal levels at which humans can sustain life are very limiting. But besides humans, more than a trillion species live on earth. In the meantime, most living species, including humans, have adapted to withstand harsh conditions that are relatively harmful to life. From hot springs where water is dancing to the ice of Antarctica which is permanently covered with ice, not only from the tops of mountains to the Mariana Trench but also to the lower layers of the earth’s crust, life is spread and some organisms, deadly to humans, radiation, temperature, pressure, They have adaptations to survive. Keeping that fact in mind, let us inquire about some other planets and moons of the solar system.
The planet Venus
Although known as the twin sister of the Earth, the surface of Venus is not in the same condition as the Earth. Due to the greenhouse effect caused by the high percentage of carbon dioxide in its atmosphere, the surface temperature of Venus is higher than that of Mercury, which is located closer to the Sun. Not only that, the pressure on the surface of Venus is only ninety times that of the Earth. But when Venus is about fifty kilometers above the surface, not only the air pressure but also the temperature is very close to the conditions of the Earth.
Located at this level is the sulfuric acid cloud layer of Venus. There is a possibility of some form of life in these clouds. A number of micro-organisms that live in clouds as well as micro-organisms that live in highly acidic environments can be identified on Earth. Several chemical substances emitted due to biological reactions have been observed in the atmosphere of Venus and it is not yet confirmed whether their origin is extraterrestrial life or a natural cause.
I spoke of structures resembling bacterial fossils contained in an asteroid from Mars. Life on Mars has been around for centuries. Similar to the Earth, it can be seen how the polar ice sheets are deposited and how they change with the seasons. But Mars has a very thin atmosphere compared to Earth. It also has a cold climate due to its distance from the Sun.
Even on a hot summer day, its temperature is only twenty degrees Celsius. Although the surface of Mars is a cold desert, there is a great possibility for life to exist in the ice layers located on its surface. There are many Earth bacteria that can live under the environmental conditions of Mars and a similar type of life can exist on Mars at present.
Jupiter’s moon Europa
If you have read Arthur C. Clarke’s 2061 Space Adventure, there is no reason to forget the Europa moon. Although slightly smaller than our moon, the amount of water on Europa is twice the capacity of Earth’s oceans. A large percentage of Europa’s atmosphere consists of life-friendly oxygen gas. But because this atmosphere is much thinner than the Earth’s atmosphere, the air pressure is very low.
Europa’s surface consists of an ice sheet with a thickness of about fifteen to twenty kilometers. Below it is an underground ocean formed by salt water. As a result, a magnetic field similar to Earth’s has been created on Europa’s moon. Europa’s moon has a high probability of life originating from the underground chambers and volcanoes mentioned at the beginning of this article, as well as the potential for those organisms to evolve into more complex multicellular organisms.
Saturn’s moon Titan
The moon Titan is the only place in the Solar System other than Earth that has liquid oceans on its surface. Because it is located very far from the Sun, the temperature on Titan is as low as minus 179 degrees Celsius. Under those conditions, water is no longer liquid. Therefore, the oceans, rivers, and lakes on Titan are made of hydrocarbon compounds such as ethane and methane.
Although Titan is a satellite, its size is greater than that of Mercury. And similar to Earth, there is an atmosphere rich in nitrogen. The air pressure here is only sixty percent higher than the ground. Therefore, the air pressure felt on Titan is similar to the pressure felt when diving five meters deep on Earth. The possibility of life on Titan, which is very similar to Earth, is also very high. But due to the very low temperature, the life that occurs here may have a completely different biochemical composition than the Earth.
Saturn’s moon Enceladus
This satellite, whose equatorial radius is smaller than the length of Sri Lanka, is unique because of the jets of water projected from its surface into space. It provides a good indication of an internal ocean of liquid water beneath Enceladus’ icy surface. It is also proof that the activity of hot springs inside the satellite is at a very high level. Enceladus, which has a similar environment to Jupiter’s moon Europa, has a high possibility of life. Further factors related to that may be discovered through future space research.
When we hear the word extraterrestrial life, we think of green-colored, large-eyed, flying saucer-like humanoid creatures that are often seen in Hollywood movies. But real aliens are likely to be much different. Most likely they will be similar to microbial forms found in our environment or species living on the deep ocean floor…
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