If the "truth is out there," scientists are determined to find it – so much so that they've spent a message into space trying to contact aliens.
But a response could take 25 years – if it comes at all.
Messaging Extraterrestrial Intelligence (METI) International sent an encoded message into space using radio waves known as "Sonar Calling GJ273b," which the organization's president and founder Doug Vakoch, believes could be received by intelligent life.
"[The message is] distinctive because it's designed with extraterrestrial SETI scientists in mind. We sent the sort of signal we'd want to receive here on Earth," he said in an interview with CNET.
METI's purpose, along with the well-known Search for Extraterrestrial Intelligence (SETI), has a number of missions, including understanding and communicating "the societal implications and relevance of searching for life beyond Earth, even before detection of extraterrestrial life."
It also conducts programs to "foster increased awareness of the challenges facing our civilization’s longevity" among other directives.
The San Francisco-based METI sent its message toward the red dwarf star GJ 273 (also known as Luyten's Star), 12 light-years away from Earth. The message was sent in October from the Eiscat transmitter in Tromsø, Norway and included details such as basic math and science, as well as information on mankind's understanding of time.
In a statement obtained by CNET, METI said it wanted to know if intelligent life understood the message and then go from there.
"In a reply message, I would first want to know that the extraterrestrials understood what we said in our first message," METI said in the statement. "The easiest way to do this is to repeat our message, but in expanded form. We tell them that '1 + 1 = 2.' They could let us know that they understand that '10 + 10 = 20.'"
Pressing ahead despite concerns
While some luminaries, such as Stephen Hawking, have warned against trying to contact extraterrestrials, Vakoch said contact is already being endorsed by many people.
"Everyone engaged in SETI is already endorsing transmissions to extraterrestrials through their actions," Vakoch said in an interview with Newsweek. "If we detect a signal from aliens through a SETI program, there’s no way to prevent a cacophony of responses from Earth."
Vakoch added that once news of the initial contact has appeared, it would become almost impossible to stop anyone from trying to contact them on their own. "Once the news gets out that we’ve detected extraterrestrials, anyone with a transmitter can say whatever they want."
When can we expect a possible response?
Any response probably would be forthcoming in at least 25 years due to the distance the message has to travel between Earth and GJ273b.
The exoplanet was chosen because of its visibility from Earth's northern hemisphere, even if it is not the closest potentially inhabited exoplanet to Earth. That distinction belongs to Proxima b, which is just 4 light-years away.
Earlier this week, scientists discovered a new exoplanet, Ross 128 b, that is 11 light-years away from Earth. It orbits a very quiet red-dwarf star, meaning it does not have to deal with issues such as deadly ultraviolet or X-ray radiation and could also be home to life.
One light-year is approximately 5.88 trillion miles.
Sonar calling GJ273b is not the first message sent to space. The first was the Arecibo message, sent in 1974. The Arecibo message is expected to take 25,000 light-years to reach its target of the M13 star cluster.
While hopeful of receiving a response, Vakoch says we may never hear anything from another intelligent civilization.
"Practically speaking, if we get a signal from Luyten's Star, it will mean the Milky Way is teeming with life. It's certainly possible," Vakoch said. "It seems more likely that we'll need to target not just one star, but hundreds, thousands, or even millions before we get a reply back."