There are many old stories and myths about extraterrestrial life.
This has not only been a hot issue for debate among the scientific community but has also been an attractive subject among the public. The issue that once was regarded as a secret, as well as a source of anxiety for the public, now constitutes a major portion of Hollywood movies and science fiction books. But the question remains as to how serious and real the possibility of extraterrestrial life can be and if there are any solid scientific arguments supporting the idea.
Over the past few decades, with the rapid progress in the development of such technologies as communication, satellites, radio telescopes as well as biological science, there have been ample findings and evidence supporting the idea of the existence of extraterrestrial life. The distinct clues and evidence, when put together, have driven the scientific community to the conclusion that the existence of life is not just limited to our Earth and indeed, it may exist on other planets in our solar system or even in other similar planetary systems in our Milky Way galaxy or other galaxies too. In order to better understand the arguments for the existence of extraterrestrial life, the criteria that led to the formation of life on Earth have to be understood:
Formation of life on Earth
The scientific research has suggested the following events and parameters for the formation of life on our planet:
- The formation of water on Earth as the most important criteria for the formation of the primitive blocks of life on Earth. Water means oxygen, which is the basic component of any form of life.
- The collision of asteroids and comets with Earth. It is believed that such collisions may have led to the combination of amino acids and the formation of life’s building blocks on Earth.
Having the above arguments in mind, let us take a look at some of the reported scientific findings among the many others:
- In September 2015, NASA reported the discovery of liquid water on Mars. The finding suggests that the liquid water may have led to the formation of living organisms on the planet.
- In 2004, methane was discovered in Mars’s atmosphere. Since most of the methane in Earth’s atmosphere has been produced by the bacteria and other living species, this discovery suggests the possibility of life on Mars.
- Confirmation of the existence of a giant ocean beneath the icy exterior shell of the Saturn’s moon named Enceladus.
- The existence of lakes made of liquid methane on the surface of the Saturn’s biggest moon Titan. Later experiments suggested the possibility of a methane-based life on Titan.
The full scientific study about the possibility of extraterrestrial life was first carried out in 1961 by the astronomer Frank Drake. Through a comprehensive study of the conditions needed for the existence of life on a typical planet, Drake devised a formula named as “Drake equation,” based on which it was possible to calculate the number of planets in our Milky Way galaxy qualified for the hosting of intelligent life. The equation highly depended on parameters that were not available at his time; however, based on the existing observations, he applied his formula and found the figure of 10,000 for the number of planets in our galaxy. The calculation was repeated again in 2001 using updated and more precise figures for the parameters used in the Drake formula. As a result, it raised the number to hundreds of thousands of planets with the possibility of some inhabitable planets within a few light years from our solar system.
There are now experimental clues about the existence of intelligent life in nearby planetary systems in our galaxy. One example is the result of a research by astronomers in 2003 by the big telescope in Puerto Rico that led to the detection of a radio signal in a portion of the sky that had no previous record. The signal that came from a point of the sky between Aries and Pisces constellations was regarded as a good candidate for hosting intelligent life on some planets in our Milky Way galaxy.
With the introduction of more powerful telescopes, radio telescopes as well as satellites designed for surveying of life on other planets, there is much hope for a definite conclusion in the near future and maybe in the next few decades.
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