If a person is lost in the desert, he has two options. They can search for civilization, or they can be easy to spot by lighting a fire or writing HELP in big letters. For scientists interested in the question of whether intelligent aliens exist, the options are much the same.
For more than 70 years, astronomers have searched for optical or radio signals from other civilizations looking for extraterrestrial intelligence, called SETI. Most scientists are confident that life exists on many of the 300 million potentially habitable worlds in the Milky Way galaxy. Astronomers also believe that there is a decent chance that some life forms have developed intelligence and technology. But no signs of another civilization have ever been detected, a mystery called “The Great Silence.”
While SETI has long been a part of mainstream science, METI, or Messaging Extraterrestrial Intelligence, has been less common.
I am a professor of astronomy and have written extensively on the search for life in the universe. I also serve on the advisory board of a nonprofit research organization that is designing messages to send to extraterrestrial civilizations.
In the coming months, two teams of astronomers will send messages into space in an attempt to communicate with any intelligent aliens that may be listening.
These endeavors are like lighting a big bonfire in the woods and hoping someone will find you. But some people wonder if it’s wise to do this at all.
The history of METI
The first attempts to contact life outside of Earth were quixotic messages in a bottle.
In 1972, NASA launched the Pioneer 10 spacecraft toward Jupiter with a plaque featuring a line drawing of a man and a woman and symbols to show where the spacecraft originated. In 1977, NASA followed up with the famous Golden Disc attached to the Voyager 1 spacecraft.
These spacecraft, as well as their twins, Pioneer 11 and Voyager 2, have now left the solar system. But in the vastness of space, the chances of these or any other physical objects being found are incredibly minuscule.
Electromagnetic radiation is a much more effective beacon.
Astronomers broadcast the first radio message designed for extraterrestrial ears from the Arecibo Observatory in Puerto Rico in 1974. The series of 1’s and 0’s was designed to transmit simple information about humanity and biology and was sent towards the globular cluster M13. Since M13 is 25,000 light-years away, you shouldn’t hold your breath for an answer.
In addition to these determined attempts to send a message to aliens, the whimsical signals of radio and television broadcasts have been leaking into space for nearly a century. This ever-expanding earthly babble bubble has already reached many stars. But there’s a big difference between a focused burst of radio waves from a giant telescope and a diffuse leak: The faint signal from a show like “I Love Lucy” fades beneath the hum of radiation left over from the Big Bang shortly after it hits. leave the solar system
Sending new messages
Almost half a century after the Arecibo message, two international teams of astronomers are planning new attempts at extraterrestrial 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 diameter of 500 meters (1,640 feet), will emit a series of radio pulses over a wide swath of heaven. . These on and off pulses are like the 1’s and 0’s 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 location of the Earth and a timestamp. The team is sending the message toward a group of millions of stars near the center of the Milky Way, about 10,000 to 20,000 light-years from Earth. While this maximizes the pool of potential aliens, it does mean that it will be tens of thousands of years before Earth can get an answer.
The other attempt points to a single star, but with the potential for a much faster response. On October 4, 2022, a team from the Goonhilly Satellite Earth Station in England will transmit a message to 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 host liquid water and potentially life as well. TRAPPIST-1 is only 39 light-years away, so it could take up to 78 years for intelligent life to receive the message and for Earth to get the answer.
The prospect of extraterrestrial contact is fraught with ethical questions, and METI is no exception.
The first is: Who speaks for the 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’re lost in the woods, being found is obviously a good thing. When it comes to whether humanity should broadcast a message to aliens, the answer is much less clear.
Before he died, iconic physicist Stephen Hawking spoke openly about the danger of contacting aliens with superior technology. He argued that they could be evil and, if given the location of Earth, could destroy humanity. Others do not see any extra risk, since a truly advanced civilization would already know of our existence. And there is interest. Russian-Israeli billionaire Yuri Milner has offered $1 million for the best design of a new message and an effective way to deliver it.
To date, there are no international regulations governing METI, so experiments will continue, despite concerns.
For now, intelligent aliens remain in the realm of science fiction. books like The three body problem by Cixin Liu offer bleak and thought-provoking perspectives on what the success of METI’s efforts might look like. It doesn’t end well for humanity in the books. If humans ever make contact in real life, I hope the aliens will come in peace.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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