Throughout the years, the alien has been one of the most popular topics in science fiction movies and books. In fact, a lot of people are getting interested and would like to know if there is really another kind of living creature out there in space. What do they look like? Where are they coming from? Will they come and attack Earth? All these questions are the most frequently asked by the general public.
The main question that interests astronomers is whether there is anyone out there in space. Scientists are trying to search for life that may exist elsewhere in the universe by using instruments and different ways to communicate with extraterrestrial life. As no evidence has proven that there is or there isnt, this seems to be a very open question. Some astronomers worked on the above question by attempting to estimate the number of advance technical civilizations in the Milky Way galaxy.
They require assigning numerical values to quantities such as the number and age of stars; the abundance of planetary systems and the likelihood of the origin of life within them; the probability of the evolution of intelligent life and the lifetime of technical civilization. Results indicated that there were around a million technical civilizations in our Galaxy alone. This may seem to be such a large number. But there may be as many as 250 billion stars in the Milky Way Galaxy. Even with a million civilizations, less than one star in 250,000 would have a planet inhabited by an advanced civilization.
Since we have little idea which stars are likely candidates, we will have to examine a huge number of them. (Sagan, 1979) If there are a million technical civilizations in the Milky Way Galaxy, the average separation between civilizations will be about 300 light years. (Sagan, 1979) If this assumption is correct, the time to communicate back and forward between two civilizations would be 600 years. As we can see it takes a very long time to communicate and it is most unlikely that we will get any result back within our human life time since humans only started to send messages to outer space in the 1970s.
The first message that was attempted in 1974 by Frank Drake, he was the pioneer of the Search for Extraterrestrial Intelligence (SETI) Institute. Dr. Drakes message to the stars was beamed from the Arecibo radio telescope in Puerto Rico. It contained just 1,679 bits of information. It consisted of a rectangular grid that aliens could reconstruct to provide a crude diagram of the solar system and of a DNA double-helix molecule, along with a smattering of other information. (Chandler, 1999) A recent message that was sent to outer space utilized a similar concept.
Yvan Dutil and M. Stephane Dumas of the Defence Research Establishment Valcartier near Quebec City constructed a 22 page message which included several pages about mathematics and basic physics, a few about biology and geography, a diagram, some basic data about our solar system and a request to the recipients to send back some information about the world they call home. (Chandler, 1999) The reason to send such data is that scientists believed that mathematics and science are the two universal languages that the aliens should be about to understand if their civilization is advanced enough.
Attempts to detect radio signals began in the early 1930s when Karl Jansky constructed a radio telescope, which started to detect radio waves from outer space. (Sagan, 1997) However, until this point, with all the improvement of our technology, we still cannot find any signal received from another civilization. The detection of radio signals from space would indicate that the origin of life is not an extraordinarily unlikely event. It would prove that simple forms of life do generally evolve into complex and intelligent forms, as on Earth.
The most likely case is that the message will be form a civilization which the same level or even far superior technology. Such message will deliver an invaluable piece of knowledge: it is possible to live through technological adolescence, avoid technological disaster or even clear out the differences among human beings or separate races and nationalities, religions and sexes and help ally the whole world together against the extraterrestrial intelligent beings.
The National Aeronautics and Space Administration (NASA) also take part in the search for life in space but with a different approach. They are trying to look for microbes instead of civilization. The whole idea started when NASA discovered that bacteria could survive in severe environments, even extraterrestrial ones. The incident happened when someone coughed on the circuit boards when Surveyor 3 was being prepared for lunch. The bacteria had been freeze-dried in space for three years on the moons surface but were quickly revived once back on Earth.
Dawson, 1999) The research for microbes in the extreme environment then began from here, on Earth. They study the surprising findings that creatures can live in about-boiling temperature in places like deep undersea sulfur vents, as well as at enormous pressure deep under the Earths surface, and in the frozen ice at the poles. (Fox, 1999) All these findings can help NASA stretch out and road map for the search for life. Not only scientists can enjoy the search for extraterrestrial intelligence life in space, even a normal person can participate in this wonderful event.
Due to the lack of computer power to process the enormous reams of data collected by the radio telescope, SETI developed a program called SETI@home to solicit the help for computer users all over the world. Each computer each time will process small, 250-kilobyte chunks of data collected by the SETI program run by the University of California at Berkeley. SETI@home works like a screen saver. If your computer is idle for more than a few minutes, the program kicks in and processes data while youre not using it.
After a few days, a message on your screen will tell you that the data has been processed and you have to connect to the Internet and the data will automatically upload to Berkeley. (Naeye, 1998) Some astronomers pointed out that we maybe the only kind of life form in the universe. Mario Livio, an Astronomer at Space Telescope Science Institute in Baltimore, makes the case by connecting between the suns lifetime and the appearance of intelligent life on earth. This link should hold true for the stars that are similar to our sun in the universe and can offer an equal opportunity for intelligent life forms to arise elsewhere in the space.
Livio argued that based on life first emerged on earth a few hundred million years after its formation, it took nearly 3 billion years fro the first multi-celled organisms to appear. It took almost another billion year before life emerged from the sea onto the land. The earliest humans appeared less than 4 million years ago, which is about a quarter point of our suns lifetime. (Villard and Livio, 1998) If all of that was just a coincidence, it is very possible that other civilizations had to take much longer to arise, or even take longer than the life of a star.
Livio also argued that as sunlight provides far more energy for life than other chemical processes, biological evolution is intimately linked to the Suns behaviour. (Villard and Livio, 1998) Only a small minority of stars, like our sun, can support complex life. Low-mass stars have a tiny zone in which a planet can support life. But that zone is so colas to the star that the planet will be tightly locked, so only one hemisphere receives sunlight. High-mass stars have large life zones but these stars die before life can evolve on the planets.
Planets in multiple star systems may end up with unstable orbits or orbits that result in extreme climate fluctuations, in which life will unlikely to form. (Andreadis, 1998) The attribution of our planet itself also has a great impact of life forming. Our planets atmosphere has the ability to block out destructive UV radiation from the sun. If the Big Bang theory is correct and accurate enough, we are now about 13 billion years after the Big Bang. Between this period of time, the formation of the universe, stars and their stellar systems took place.
When we add the time it takes for evolution to proceed, even if such civilizations do exist, it is very difficult to imagine the thought of a civilization, which might have evolved a few million years ahead of us. However, the existence of microbes in the universe is very possible. The search for extraterrestrial life will continue and we have to be patient since the communication really takes time. Actual proof of their existence will have to await advances in the technology of biology and astronomy.
