Thursday, June 29, 2017

Greetings, E.T. (Please Don’t Murder Us.)

On Nov. 16, 1974, a few hundred astronomers, government officials and other dignitaries gathered in the tropical forests of Puerto Rico’s northwest interior, a four-hour drive from San Juan. The occasion was a rechristening of the Arecibo Observatory, at the time the largest radio telescope in the world. The mammoth structure — an immense concrete-and-aluminum saucer as wide as the Eiffel Tower is tall, planted implausibly inside a limestone sinkhole in the middle of a mountainous jungle — had been upgraded to ensure its ability to survive the volatile hurricane season and to increase its precision tenfold.

To celebrate the reopening, the astronomers who maintained the observatory decided to take the most sensitive device yet constructed for listening to the cosmos and transform it, briefly, into a machine for talking back. After a series of speeches, the assembled crowd sat in silence at the edge of the telescope while the public-address system blasted nearly three minutes of two-tone noise through the muggy afternoon heat. To the listeners, the pattern was indecipherable, but somehow the experience of hearing those two notes oscillating in the air moved many in the crowd to tears.

That 168 seconds of noise, now known as the Arecibo message, was the brainchild of the astronomer Frank Drake, then the director of the organization that oversaw the Arecibo facility. The broadcast marked the first time a human being had intentionally transmitted a message targeting another solar system. The engineers had translated the missive into sound, so that the assembled group would have something to experience during the transmission. But its true medium was the silent, invisible pulse of radio waves, traveling at the speed of light.

It seemed to most of the onlookers to be a hopeful act, if a largely symbolic one: a message in a bottle tossed into the sea of deep space. But within days, the Royal Astronomer of England, Martin Ryle, released a thunderous condemnation of Drake’s stunt. By alerting the cosmos of our existence, Ryle wrote, we were risking catastrophe. Arguing that ‘‘any creatures out there [might be] malevolent or hungry,’’ Ryle demanded that the International Astronomical Union denounce Drake’s message and explicitly forbid any further communications. It was irresponsible, Ryle fumed, to tinker with interstellar outreach when such gestures, however noble their intentions, might lead to the destruction of all life on earth.

Today, more than four decades later, we still do not know if Ryle’s fears were warranted, because the Arecibo message is still eons away from its intended recipient, a cluster of roughly 300,000 stars known as M13. If you find yourself in the Northern Hemisphere this summer on a clear night, locate the Hercules constellation in the sky, 21 stars that form the image of a man, arms outstretched, perhaps kneeling. Imagine hurtling 250 trillion miles toward those stars. Though you would have traveled far outside our solar system, you would only be a tiny fraction of the way to M13. But if you were somehow able to turn on a ham radio receiver and tune it to 2,380 MHz, you might catch the message in flight: a long series of rhythmic pulses, 1,679 of them to be exact, with a clear, repetitive structure that would make them immediately detectable as a product of intelligent life. (...)

Now this taciturn phase may be coming to an end, if a growing multidisciplinary group of scientists and amateur space enthusiasts have their way. A newly formed group known as METI (Messaging Extra Terrestrial Intelligence), led by the former SETI scientist Douglas Vakoch, is planning an ongoing series of messages to begin in 2018. And Milner’s Breakthrough Listen endeavor has also promised to support a ‘‘Breakthrough Message’’ companion project, including an open competition to design the messages that we will transmit to the stars. But as messaging schemes proliferate, they have been met with resistance. The intellectual descendants of Martin Ryle include luminaries like Elon Musk and Stephen Hawking, and they caution that an assumption of interstellar friendship is the wrong way to approach the question of extraterrestrial life. They argue that an advanced alien civilization might well respond to our interstellar greetings with the same graciousness that Cortés showed the Aztecs, making silence the more prudent option. (...)

Before Doug Vakoch had even filed the papers to form the METI nonprofit organization in July 2015, a dozen or so science-and-tech luminaries, including SpaceX’s Elon Musk, signed a statement categorically opposing the project, at least without extensive further discussion, on a planetary scale. ‘‘Intentionally signaling other civilizations in the Milky Way Galaxy,’’ the statement argued, ‘‘raises concerns from all the people of Earth, about both the message and the consequences of contact. A worldwide scientific, political and humanitarian discussion must occur before any message is sent.’’

One signatory to that statement was the astronomer and science-fiction author David Brin, who has been carrying on a spirited but collegial series of debates with Vakoch over the wisdom of his project. ‘‘I just don’t think anybody should give our children a fait accompli based on blithe assumptions and assertions that have been untested and not subjected to critical peer review,’’ he told me over a Skype call from his home office in Southern California. ‘‘If you are going to do something that is going to change some of the fundamental observable parameters of our solar system, then how about an environmental-impact statement?’’

The anti-METI movement is predicated on a grim statistical likelihood: If we do ever manage to make contact with another intelligent life-form, then almost by definition, our new pen pals will be far more advanced than we are. The best way to understand this is to consider, on a percentage basis, just how young our own high-tech civilization actually is. We have been sending structured radio signals from Earth for only the last 100 years. If the universe were exactly 14 billion years old, then it would have taken 13,999,999,900 years for radio communication to be harnessed on our planet. The odds that our message would reach a society that had been tinkering with radio for a shorter, or even similar, period of time would be staggeringly long. Imagine another planet that deviates from our timetable by just a tenth of 1 percent: If they are more advanced than us, then they will have been using radio (and successor technologies) for 14 million years. Of course, depending on where they live in the universe, their signals might take millions of years to reach us. But even if you factor in that transmission lag, if we pick up a signal from another galaxy, we will almost certainly find ourselves in conversation with a more advanced civilization.

It is this asymmetry that has convinced so many future-minded thinkers that METI is a bad idea. The history of colonialism here on Earth weighs particularly heavy on the imaginations of the METI critics. Stephen Hawking, for instance, made this observation in a 2010 documentary series: ‘‘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.’’ David Brin echoes the Hawking critique: ‘‘Every single case we know of a more technologically advanced culture contacting a less technologically advanced culture resulted at least in pain.’’

by Steven Johnson, NY Times Magazine |  Read more:
Image: Paul Sahre
[ed. If you find this topic interesting, I'd also suggest The Three-Body Problem by Liu Cixin.]