"We don't know when earthlings will discover ET. It could be 1,000 years from now, or in our lifetimes. It could be next year, when FAST gets going on the sky surveys," said Dan Werthimer, chief scientist for the SETI Research Center at University of California, Berkeley.
However, with no clues of extraterrestrial life over the past five decades, questions are constantly asked as whether the search methods are appropriate. "Some strange signals have been found, but it's hard to confirm their origins, because these signals do not repeat," says Li Di, chief scientist of China's new FAST Radio telescope. "We look for not only television signals, but also atomic bomb signals. We'll give full play to our imaginations when processing the signals," Li says. "It's a complete exploration, as we don't know what an alien is like."
With a dish the size of 30 football fields, China's new FAST radio telescope, which measures 500 meters in diameter, dwarfs Puerto Rico's 300-meter Arecibo Observatory. Having the world's largest and most powerful new radio telescope, the Five-hundred-meter Aperture Spherical Telescope (FAST), "We can receive weaker and more distant radio messages," said Wu Xiangping, director-general of the Chinese Astronomical Society, "It will help us to search for intelligent life outside of the galaxy and explore the origins of the universe," he added underscoring the China's race to be the first nation to discover the existence of an advanced alien civilization.
The dish will have a perimeter of about 1.6 kilometers, and there are no towns within five kilometers, giving it ideal surroundings to listen for signals from space. Scientists have depicted it as a super-sensitive "ear", capable of spotting very weak messages – if there are any – from "cousins" of human beings.
The telescope, nicknamed Tianyan, or the Eye of Heaven, can accurately image twice as much the sky as the Arecibo Observatory in Puerto Rico, which had previously been the world's largest single-dish radio telescope, with double sensitivity and five to 10 times the surveying speed.
Douglas Vakoch, president of METI International, an organization promoting messaging outer space in the search for extraterrestrial intelligence, noted that astronomers worldwide will be invited to use the facility through a competitive review of observing proposals.
"By opening FAST to use by the broader international community, China is demonstrating its commitment to fostering astronomy as a global scientific enterprise," he told Xinhua, saying it may lead to "discoveries beyond our wildest imagination."
As for FAST's scientific missions, Vakoch said it will be used to look for the signatures of complex organic molecules in interstellar space, which will show how widely the basic building blocks of life are distributed throughout the cosmos.
"For over a half century, astronomers have been using radio telescopes to answer the haunting question, 'Are we alone?' But astronomers face a daunting challenge: the signals they seek are so weak that an incredibly sensitive telescope is needed to detect them," he said.
"FAST's innovative design and huge collecting area give it unsurpassed speed and sensitivity, making it vital to the search for extraterrestrial intelligence in the coming decades," said Vakoch. "We can expect China to become a world leader in the search for extraterrestrial intelligence because of its demonstrated commitment in building FAST."
However, FAST will not initially be outfitted with the signal processing capabilities to search for aliens, he said. This technology will be added at a later stage, and when that happens, FAST will be able to scan the heavens for signals that "can't be created by nature, but only by advanced civilizations," Vakoch said.
Sometimes, radio telescopes are "confused" by signals from astronomical objects. For example, astronomers once mistook signals from a pulsar for extraterrestrial signs, because a pulsar can also give out very stable periodical signals.
"It is highly possible that life on other planets is entirely different from that on Earth, and it might not be carbon-based," says Jin Hairong, deputy curator of Beijing Planetarium.
Liu Cixin, a Chinese science fiction writer and winner of the Hugo Award for his novel The Three Body Problem (check out the fascinating video trailer below), points out the current method assumes that aliens also communicate in radio waves. "But if it's a truly advanced civilization, it is possible to use other more advanced forms of communication, such as gravitational waves."
But Mao Shude with the National Astronomical Observatories of China and professor of astrophysics at the Jodrell Bank Observatory believes many methods deserve a try: "Who knows what they are and how they think? "When we study the origin of life, we risk going down a blind alley if we only have one sample from Earth," Mao says. "If we could find more samples in the universe, we could look at the puzzle more comprehensively and solve it more easily."
Shude gives an example in astronomy to explain the limitations of a single sample. "When scientists started to look for planets around Sun-like stars, they thought it must be difficult as their period might be as long as a year. However, the first such planet discovered outside our solar system takes only four days to orbit its host star – much faster than astronomers expected. At that time, some people doubted it, showing how the example of our solar system narrowed their thinking."
"If we really discover extraterrestrial life, I'd like to know how life spreads in the universe. Is it distributed uniformly in space, or clustered?" Mao wonders.
However, the idea communicating with aliens comes with concerns.
Astrophysicist Stephen Hawking has warned that communicating with aliens could be a threat to Earth: "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans."
The Three Body Problem by Liu Cixin depicted the universe as a jungle with every civilization as a hidden hunter. Those who are exposed will be eliminated.
But Han Song, another leading Chinese science fiction writer, believes humans naturally want to connect, citing the Internet as proof. "I think aliens might think similarly. It is a biological instinct to connect with each other. Everyone wants to prove that they are not alone in the universe. Loneliness is intolerable to humans," he says.
He also points out that the contact will be driven by curiosity and real requirements. "Humans will ultimately go to space to find resources and expand their living area, so it will be hard to avoid aliens. Contact with them, especially those with more advanced intelligence, may help us leap forward in civilization."
Regardless of the theoretical debate, scientists have never wavered in the search. "I think we shall call out. As a matter of fact, we have been yelling for years, and our radios and televisions are broadcasting in space all the time," Mao says, "Aren't you curious what our counterparts would look like?
If they are inferior or equal to us in terms of civilization, we won't be easily destroyed. If they are much more intelligent than us, they wouldn't be so narrow-minded as to compete with us. Some worry they will come to rob us of our natural resources, but they likely have the power to transform the entire globe already. What's the point of eliminating a much lower civilization?"
Mao believes the result will be significant however it turns out. "If we find other life, it will undoubtedly be the most important scientific discovery in our history; if not, it shows that life on Earth is unique and we should respect life and cherish each other.
"No matter the outcome, we shall never stop searching, and I hope to hear more voices and contributions from Chinese scientists."