In the coming months, two teams of astronomers are going to send messages into space in an attempt to communicate with any intelligent aliens who may be out there listening.

These efforts are like building a big bonfire in the woods and hoping someone finds you. But some people question whether it is wise to do this at all.

THE HISTORY OF METI

Early attempts to contact life off of Earth were quixotic messages in a bottle.

In 1972, NASA launched the Pioneer 10 spacecraft toward Jupiter, carrying a plaque with a line drawing of a man and a woman and symbols to show where the craft originated. In 1977, NASA followed this up with the famous Golden Record attached to the Voyager 1 spacecraft.

These spacecraft—as well as their twins, Pioneer 11 and Voyager 2—have now all left the solar system. But in the immensity of space, the odds that these or any other physical objects will be found are fantastically minuscule.

Electromagnetic radiation is a much more effective beacon.

Astronomers beamed the first radio message designed for alien ears in 1974 from the Arecibo Observatory in Puerto Rico. The series of 1s and 0s was designed to convey simple information about humanity and biology and was sent toward the globular cluster M13. Since M13 is 25,000 light-years away, you shouldn’t hold your breath for a reply.

In addition to these purposeful attempts at sending a message to aliens, wayward signals from television and radio broadcasts have been leaking into space for nearly a century. This ever-expanding bubble of earthly babble has already reached millions of stars. But there is a big difference between a focused blast of radio waves from a giant telescope and diffuse leakage—the weak signal from a show like I Love Lucy fades below the hum of radiation left over from the Big Bang soon after it leaves the solar system.

SENDING NEW MESSAGES

Nearly half a century after the Arecibo message, two international teams of astronomers are planning new attempts at alien communication. One is using a giant new radio telescope, and the other is choosing a compelling new target.

One of these new messages will be sent from the world’s largest radio telescope, in China, sometime in 2023. The telescope, with a 1,640-foot (500-meter) diameter, will beam a series of radio pulses over a broad swath of sky. These on-off pulses are like the 1s and 0s of digital information.

The message is called “The Beacon in the Galaxy” and includes prime numbers and mathematical operators, the biochemistry of life, human forms, the Earth’s location, and a time stamp. The team is sending the message toward a group of millions of stars near the center of the Milky Way galaxy, about 10,000 to 20,000 light-years from Earth. While this maximizes the pool of potential aliens, it means it will be tens of thousands of years before Earth may get a reply.

The other attempt is targeting only a single star, but with the potential for a much quicker reply. On October 4, 2022, a team from the Goonhilly Satellite Earth Station in England will beam a message toward the star TRAPPIST-1. This star has seven planets, three of which are Earth-like worlds in the so-called Goldilocks zone—meaning they could be home to liquid and potentially life, too. TRAPPIST-1 is just 39 light-years away, so it could take as few as 78 years for intelligent life to receive the message and for Earth to get the reply.

ETHICAL QUESTIONS

The prospect of alien contact is ripe with ethical questions, and METI is no exception.

The first is: Who speaks for Earth? In the absence of any international consultation with the public, decisions about what message to send, and where to send it are in the hands of a small group of interested scientists.

But there is also a much deeper question. If you are lost in the woods, getting found is obviously a good thing. When it comes to whether humanity should be broadcasting a message to aliens, the answer is much less clear-cut.