The existence of life beyond planet earth has been one of the most exciting questions for centuries. By implementing imaginative ideas, scientists all over the world are trying to find an answer to this question. Astrobiology has been looking for evidence of microbial life as well as the presence of extraterrestrial intelligences.
The probability of detecting extraterrestrial microbes isn’t necessarily an impossible task. This can be easily compared to early life on earth many billions of years ago, a time when our planet was inhabited by microorganisms. Dividing earth’s existence into six equal parts, it wasn’t until the last part of its history that organisms took on certain anatomical shapes and forms. For 500,000 years, which equals out to about 0.01 percent of the lifespan of our planet, humans have been living on it. Based on this knowledge, we must recognize that intelligence is a very exclusive version of life’s existence.
Nevertheless, the development of other thinking beings is not unlikely. The American astronomer Professor Carl Sagan pointed out that every being on earth would benefit from a higher intelligence, believing in its development anywhere where life has the means to exist. Time is a key factor to why there may be a relatively high number of extraterrestrial intelligences in the future. As our solar system is part of a later star cycle, with respect to the age of the universe, scientists believe that life in cosmic biotopes has already gone through an earth-like evolutionary cycle.
The number of possible star civilizations can only be estimated. The astronomer Frank Drake guesses the Milky Way alone to have approximately 100 million inhabitants of some sort of extraterrestrial civilization. In search for extraterrestrial life, astronomers look for planets being part of another solar system. Unfortunately, the earth is the only biology-friendly planet in our solar system.
In 1999 researchers at Mount Stromolo Observatory discovered such a celestial body for the first time. They named it 98-BLG-35, its location 30,000 light years away. Its size can be compared to the one of our planet earth, rotating in a zone habitable for human life. Its distance from its sun is ideal for water to take on its liquid form, an optimal condition for life. Unfortunately, we are unable to reach this planet as even the fastest shuttle, the Saturn V at a speed of over 40,000 km/h would take more than 26 years to only pass one light year.
Wondering about life in the universe, we ask ourselves the question: how and where could such life exist? A study done by NASA in 2001 showed that the first complex molecules, the building blocks of life indeed develop and survive in the freezing temperatures of the cosmos. For experimental purposes astrobiologists bred artificial chunks of ice under space conditions and irradiated them with ultraviolet light, similar to the light that is being emitted by stars. Hundreds of organic compounds were observed displaying very complex behavior. As soon as the irradiated ice chunks came in contact with water, they started to form several types of cell structures. These findings did suggest that life could exist anywhere in the universe. Such a cosmic cuisine could well be found within interstellar clouds. In 1998, the two astronomers Steven Taylor and Russ Gibson proved the existence of organic compounds in the electrically-charged outer zones of such molecular clouds. A primitive form of life would be quite possible in such areas. More advanced forms of life would need the existence of planets and moons for evolution to take its course.
To this day, aliens only exist in our imagination. Nevertheless, it seems that the universal law of biology leads us to results that support that fantasy. An extraterrestrial intelligence must possess an information system ensuring the reception and implementation of environmental information. Maybe aliens do not correspond exactly to those in our science-fiction films, but a certain similarity to human life, as indicated on the big screen and on television, would be quite conceivable. Until the day we will see a real alien, whether in the form of a microbe or a thinking being, we will still continue to depend on our imagination.
