NASA, ESA, M. Kornmesser
This silence has influenced a new group of experts over recent years which says it's time to stop listening and start talking - by deliberately transmitting messages into space for anyone who might be searching for them. They call the project Active SETI.
Many intellectual leaders of our age, including Stephen Hawking, say the idea behind Active SETI should be avoided at all cost, but co-founder and former director of the SETI Institute Jill Tarter pointed out a serious flaw in Hawking's philosophy.
While Hawking fears that giving aliens our cosmic address could potentially bring death and ruin - much like what happened to many groups of Native Americans when Europeans invaded North America - Tarter thinks that aliens advanced enough to skip across star systems and reach Earth will be friendly, not aggressive.
"The idea of a civilization which has managed to survive far longer than we have ... and the fact that that technology remains an aggressive one, to me, doesn't make sense," Tarter told Business Insider. "The pressure of long-term survival - of limiting population ... I think requires that the evolutionary trends that ratcheted up our intelligence ... continues to evolve into something that's cooperative and take on global scale problems."
As humans continue to evolve, our society and the way we handle controversies changes along with us.
"We're kinder and gentler than we've ever been in the past," Tarter said. According to one cross-cultural study of 31 hunter-gatherer tribes, researchers discovered evidence that more than half - 64% - engaged in warfare within a two-year period. Yet that taste for warfare has dwindled over the years, says Tarter, with the aid of emerging technologies and innovation.
So, if growing kindness is a direct consequence of humanity's time on Earth, then, according to Tarter's theory, we can expect 10,000 years from now to be less warlike than we are today - and Tarter suspects the same for other intelligent civilizations beyond our solar system.
Having spent most of her career as director of the SETI Institute, Tarter is one of the world's leading experts on the search for extraterrestrial intelligence. Her work caught the attention of Carl Sagan, who drew strongly from Tarter's life for his sci-fi book "Contact," which was later adapted into the 1997 film of the same title.
Tarter said the idea of transmitting messages into space, as opposed to listening for them, has been on members' minds since the very beginning of SETI. And while she doesn't think a visit from aliens would spell disaster, she agrees with Hawking that humanity should not be sending signals into space - at least, not yet.
"I think that when we grow up and are an advanced technology, and can take on very long-term projects, then we ought to begin transmitting," she said. "But at the moment, in our very youthful state as an emerging technology we should listen, first."
On Wednesday, the people behind WeTransfer - a cloud-based file transfer service - launched its second season of "Creative Class," which honors some of "the most influential people in the creative space." Tarter, along with three others, were recognized for their work. You can learn more about Tarter and her research in this Creative Class feature on Vimeo or below: