Extraterrestrial, a word as alien as the universe it self, Right from the beginning of mankind’s scientific endeavors, Human being have been desperately trying to answer the centuries old question that
Are we alone in the universe??
A question that breaks the imagination barriers of a human mind, extraterrestrial by definition is not conveniently located. The Extraterrestrial life represents the most obvious gap in our knowledge of nature. The seemingly infinite universe no doubt is the sign of the Almighty Allah’s vastness and artistry. The vastness of the universe it self is the biggest argument of the scientific community to defend its claim that we are not alone, there may be life outside our solar system, may be outside our galaxy. It's fairly embarrassing to admit that we can't find 90% of the universe.
“There are some 400 billion stars in our galaxy alone. If it is just us, seems like anawful waste of space”
Contact (Movie)
We all have our suppositions, our scenarios. The late astronomer Carl Segan estimated that there are a million technological civilizations in our galaxy alone. His more conservative colleague Frank Drake offers the number 10,000. John Oro, a pioneering comet researcher calculates that the Milky Way is sprinkled with a hundred civilizations. And finally there are skeptics like Ben Zuckerman, an astronomer at UCLA, who thinks we may well be alone in this galaxy if not the universe. All these estimates are highly speculative there is no conclusive evidence of any life beyond earth.
Our ideas about extraterrestrial life are what Segan called “plausibility arguments” usually shot through with unknowns, ideologies or random ought to bes. For the sake of argument if we convince our self that there is life outside this solar system the problem remains that we don’t know anything about them, We don’t know what are there life foundations what they inhale do they even breath oxygen and the list goes on and on.
In 1961 Frank Drake discussed the probability of finding an advanced civilization by giving an equation which is called the Drakes equation
N = R* * Fp * Ne * Fl * Fi * Fc * L
Going from left to right we don’t have to go any far before we hit some serious unknowns Jill tarter from SETI said “The Drakes equation is a wonderful way to organize our ignorance”
The only factor well understood is R* which is the number of stars. We know that there are over 100 billion stars in our galaxy could well be 400 billion that doesn’t count because there are billions of galaxies out there.
2nd factor Fp fraction of stars with planets there are still uncertainties since the detection equipment can only find massive planets so we could be missing planets like our very own earth .Nasa scientists are working on building a very strong and powerful telescope known as Terrestrial planet finder which would search for earth like habitable planets the next factor Ne may well be answered by TPF the number of planets with habitable environment
TPF might well be able to glean some evidence on Fl the fraction of planets on which life has originated which is a very tricky question TPF is still many years from its construction by the way.
The next factor comes out to be another giant unknown Fi How often life evolves to a condition of intelligence? There are those, like Ernst Mayr one of the great biologists of the 20th century who argue that high intelligence has occurred only once on Earth, Among something like a billion species. Billion to one long shot. But people like Paul Horowitz a Harvard physicist, argues that same data can be looked from other point of view that the only planet we know of that has life, intelligence appeared. That’s one for one proposition.
Fc tells us about the creatures that have the technology to send signals. L the final factor is representing the Longevity of civilizations the life span of a civilization another factor depending on many things. Theoretically drake has presented an equation which is not applicable to the extent of our knowledge
"Whenever anyone says, 'theoretically', they really mean, 'not really'." — Dave Parnas
How could we find such extraterrestrial beings? Rocketing off to other star systems is not feasible: Even with our fastest spacecraft, it would take more than 50,000 years to reach the nearest of these.
Despite all these uncertainties extraterrestrial life is still the most exciting area of research for the scientific community. The most honest effort for the extraterrestrial search is being carried out by SETI Search for extra terrestrial intelligence an organization which has over 2 million active members around the globe.
Late Carl Segan in one of his articles gave an overview of Extraterrestrial search and its prospects in the coming future he wrote
“Until recently there could be no such search. No matter how deep the concern or how dedicated the effort, human beings could not scratch the surface of the problem. But in the last few years - in one millionth of the lifetime of our species on this planet - we have achieved an extraordinary technological capability which enables us to seek out unimaginably distant civilizations, even if they are no more advanced than we. That capability is called radio astronomy and involves single radio telescopes, collections or arrays of radio telescopes, sensitive radio detectors, advanced computers for processing received data, and the imagination and skill of dedicated scientists. Radio astronomy has, in the last decade, opened a new window on the physical universe. It may also, if we are wise enough to make the effort, cast a brilliant light on the biological universe.”
At the American Astronomical Society Meeting, theorist Dr. Avi Loeb from Harvard Smithsonian Center for Astrophysics led a press conference on the search for Extraterrestrials “Soon, we may be eavesdropping on signals from Galactic civilizations,” said Loeb. “This is the first time in history that humans will be capable of finding a civilization like ours among the stars.” Loeb asserts that the proposed search will find “leakage” from transmissions equivalent to our broadcast television or military radars. SETI Institute’s projects had the technical capability to detect intentional signals beamed at Earth with the equivalent power to military radars.
Loeb’s search would expand the frequency range over which searches are conducted. Loeb and his co-author Matias Zaldarriaga suggest looking for accidental leakage from an alien civilization. They point out that the new Mileura Wide-Field Array’s Low Frequency Demonstrator (MWA-LFD), which is designed to study frequencies of 80-300 Megahertz, will pick up the same frequencies used by Earth technologies. On Earth, military radars are the most powerful broadcast sources, followed by television and FM radio. If similar broadcast sources exist on other planets, facilities like MWA-LFD might detect them. “The MWA-LFD is a science instrument intended to study the distant, young universe,” explained Zaldarriaga. “But by piggybacking onto its normal observations, SETI researchers could use it to look for E.T. civilizations.”
Loeb and Zaldarriaga calculate that by staring at the sky for a month, the MWA-LFD could detect Earth like radio signals from a distance of up to 30 light-years, which would encompass approximately 1,000 stars. More powerful broadcasts could be detected to even greater distances. Future observatories like the Square Kilometer Array could detect Earth-like broadcasts from 10 times farther away, which would encompass 100 million stars.
Dr. Peter Backus, Research Scientist at SETI Institute also spoke at the press conference. He stated that the MDA-LFD represents a good example of the power of the new generation of radio telescopes. Taking advantage of advances in technology, these telescopes are more powerful and flexible than the traditional, large radio telescopes. Using this same design model, the Alien Telescope Array (ATA) will ultimately have 350 dishes, each only 6 meters across Using programmable electronics, the signals from the 350 dishes can be combined to form up to 16 virtual antennas, each making independent observations. At the same time, other electronics can image an area of the sky at two different frequencies. The ATA will expand the search to higher frequencies that have far less interference and background noise than the lower frequencies that will be observed by the MWA-LFD.
Space is host to the most inhospitable environments imaginable. Nonetheless, there are subtle properties of the universe that allow the delicate process of life to exist. Indeed, it appears as if the cosmos has been “fine tuned” to permit life. Without any doubt the scientific advancements are bringing some hope for human beings quest for the Extraterrestrial life but the hopeless knowledge of the universe taunts us if we might be able to live long enough as a civilization to find the answers or may be we might extinct before greeting the Extraterrestrials
"The surest sign that intelligent life exists elsewhere in the universe is that it has never tried to contact us." Bill Watterson
