In search of ET: Fear of what’s out there causes big...

A cosmic rift has opened between Bay Area astronomers and a splinter group of San Francisco stargazers who are hell-bent on contacting space aliens, hang the consequences.

The schism pits the traditionalists, who believe humans should only look and listen for extraterrestrials to avoid tipping off evil aliens, against a rebel faction that wants to broadcast messages to intelligent beings, assuming they are altruistic.

The battle is so heated that one prominent scientist quit the Mountain View group known as SETI, or Search for Extraterrestrial Intelligence, to form METI, or Messaging Extraterrestrial Intelligence.

“Are there intelligent beings out there? We don’t know, but the only way we can find out is if we look,” said Douglas Vakoch, who founded METI International in San Francisco after the SETI board voted in 2014 against beaming messages into space.

“We’ve always assumed the extraterrestrials were looking for us,” Vakoch said. But “what if their position is, ‘No, you are the ones who are new to this game. You send us a signal first.’”

SETI has been searching for radio signals or some other sign of life beyond Earth from its Mountain View headquarters for 35 years, but with nothing to show for its effort, Vakoch and other restless alien hunters are insisting on a more active search, including employing radar and laser technology to beam more powerful multidirectional messages into space.

The problem, many SETI astronomers warn, is that, instead of an intergalactic kumbaya, intelligent extraterrestrials might very well be more inclined to enslave Earthlings and mercilessly plunder and destroy Earth.

Those who adhere to this dark theory imagine humanity as a childlike form of life lost in an Amazonian jungle crawling with skulking predators, said Andrew Fraknoi, a SETI Institute board member.

“We wonder whether the galaxy that we are in is maybe a dark forest, where it is dangerous to scream because there are creatures out there unhappy with new life forms,” said Fraknoi, an astronomer who will be teaching a course in April called Aliens in Science and Science Fiction at the University of San Francisco’s Fromm Institute. “With every strong signal we send out, we advertise our presence, and you don’t want to advertise your presence in a dark forest.”

The clash represents the first major division in the traditionally tight-knit community of astronomers, astrophysicists, philosophers, psychologists and science fiction writers who are convinced intelligent beings are out there somewhere.

Vakoch and his supporters, including some astronomers at SETI, call the dark forest analogy silly. Any predatory civilization would probably have detected us by now simply by analyzing our atmosphere, they reason. Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said.

Unconcerned about an invasion of intergalactic invertebrates who are out for our heads, Vakoch adapted a transmitter and used a Norwegian observatory in late 2017 to send a message 12.4 light-years away to Luyten’s Star, a red dwarf with a large planet in the constellation Canis Minor.

He spent years developing the message, combining mathematics and the fundamentals of language that he believes even a blind alien could understand. It was the first of what Vakoch hopes will be many signals sent by his group.

“Our goal is to say we are interested in making contact,” Vakoch said. “We may have to target hundreds and thousands and maybe millions of stars before we find anything. I view this as a reflection of the natural growth of SETI.”

There is little doubt in the minds of the stalwarts at both SETI and METI that some form of intelligent life exists out there.

There have been planets like Earth for billions of years, Fraknoi said, and that means some civilizations in the universe may have been tinkering with robotics and artificial intelligence before our solar system was even a twinkle in God’s eye.

The sun is, after all, only 4.6 billion years old. The Milky Way Galaxy, one of about 2 trillion galaxies visible through telescopes, has been around for 13.5 billion years. It is now believed that at least half of the stars in the Milky Way have planets.

Fraknoi speculates that civilizations that have existed in other solar systems for billions of years could be a self-replicating mix of the biological and the mechanical. It’s possible, he said, that such a mix could travel through space for thousands of years and still be alive to tell about it when the trip is over.

That would be a handy trick for humanity because, using Earth’s current technology, it would take 80,000 years for an astronaut to reach the closest star, Alpha Centauri, a little more than four light-years away. The vast majority of the other 200 billion stars in the Milky Way are 100 light-years or more away from Earth.

Even if aliens receive Vakoch’s electronic message 12.4 light-years away and immediately reply, we won’t know for about 25 years, assuming the communique is sent at the speed of light.

That’s the point, said Seth Shostak, a senior astronomer at the SETI Institute who supports Vakoch’s work. Given the enormous distances, he said, we may never find intelligent life if we don’t get out there and look for it.

“This notion that you have to be cryptic doesn’t make sense to me,” Shostak said. “We have not examined very much of the sky. You don’t want to cripple technology in the future by saying, ‘No transmissions into the sky because there might be nasty aliens out there.’ That’s just paranoia. Paranoia is not a good long-term policy.”

The seeds of the current debate were planted in 1974 when a team led by Frank Drake, a Cornell University astrophysicist who was later on the faculty at UC Santa Cruz, sent a digital message describing Earth and its life-forms from Puerto Rico’s Arecibo Observatory to a distant star cluster.

Several astronomers expressed concerns at the time, but they were largely ignored.

The issue began to move to the forefront in 1989 when scientists involved in SETI published a declaration of principles, including protocols on how humankind should handle a confirmed detection of intelligent extraterrestrials. No reply should be sent, the document said, until there had been international consultation on what we would say and how we would say it.

A committee of the International Academy of Astronautics released a second set of protocols in the 1990s, urging consultations with world leaders before anyone broadcasts a powerful message into space that is likely to be detectable by alien life. Stephen Hawking, the famous scientist, was among those who warned against messaging on grounds that aliens “may not see us as any more valuable than we see bacteria.”

Vakoch and Shostak were adamantly opposed to any rules that would prevent such messaging, describing it as akin to a violation of their freedom of speech. Vakoch formed METI after a vote in 2014 by the SETI Institute board rejecting his plans to broadcast messages.

Michael Michaud, an author and onetime director of the State Department’s Office of Space and Advanced Technology who helped write the protocols, holds out hope that the two sides will eventually reach a compromise.

He and other astronautics experts have proposed an inclusive consultative process to approve or reject powerful signals — those that could be detected dozens or hundreds of light years away — before Earth’s coordinates are beamed out to potential interstellar fly swatters.

“Human history is littered with examples of societies disrupted by direct contact with others, even when it was led by idealistic missionaries,” said Michaud, who has written extensively about the subject. “Ignore the Hollywood scenario of reptilian aliens landing on Earth’s surface to conquer our planet. They would not need to use futuristic weapons; the correct pesticide would do.”

Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com Twitter: @pfimrite