For the last 50 years , astronomers have been searching for word beyond Earth to no avail . scientist at the   two-year meeting   of the Messaging Extraterrestrial Intelligence ( METI ) Project in Paris put up a relatively simple reply to explain the Great Silence : us man are simply sitting in a “ astronomical zoo ” .

“ Perhaps extraterrestrials are watching humankind on Earth , much like we watch animal in a zoo . How can we get the galactic zookeepers to reveal themselves ? ” explainedDouglas Vakoch , president of METI , in a statement sent to IFLScience . “ If we went to a zoological garden and dead a zebra turn toward us , looked us in the eye , and started beat out a series of prize phone number with its hoof , that would establish a radically dissimilar human relationship between us and the zebra , and we would palpate compelled to respond . We can do the same with extraterrestrials by broadcast hefty , designed , data - rich radio signal to nearby star . ”

It may sound far - out , but Vakoch tells IFLScience in a phone interview that the controversial “ zoological garden guess ” was first presented in the seventies by astronomer   John Ball to explain theFermi paradox , coin after Italian uranologist Enrico Fermi in the 1950s who call for : If life is so abundant , who is out there and why have n’t we heard from them yet ?   With an estimated 100 billion planet in the Milky Way , it ’s potential thatmillionsof habitable terra firma - similar planets could be housing life , yet whoever is out there sits ( or floats around ) in secretiveness .

“ Our confluence focused more on questions that can be discussed through biota , psychological science , and sociology , ” Vakoch told IFLScience . “ What are the motivations of those beings out there ? If there are civilizations doing on the button what we are – merely listening and not transmitting – it would be a very quiet world . Might they be out there , and even knowing about us , but select not to respond ? ”

When it comes to interstellar communication , someone has to make the first move . old efforts to communicate with aliens , such as thegolden recordandpioneer brass , have gone unanswered – a mark that perhaps extraterrestrial life may not sympathise written or pictographic forms of communicating . Furthermore , spacecraft travel is fabulously deadening when compare to receiving set sign that journey at the speed of light . That ’s why the METI team is transmitting radio signals to space in the hope that whatever is out there may be able to decode the messages .

Voshak added that METI is preparing to send off out multiple formats delineate the hundred-and-fiftieth anniversary of the breakthrough of the periodic table .

“ Finding regularity within nature is something that we would expect scientist on another planet to understand and know about , ” he concluded .