If a person gets lost in the desert, he has two options. They can search for civilization or they can be easily spotted by building a fire or writing HELP in capital letters. For scientists interested in whether intelligent aliens exist, the options are almost the same.

For more than 70 years, astronomers have been scanning for radio or optical signals from other civilizations in search of an alien mind called SETI. Most scientists are convinced that many of them have a life 300 million potentially habitable worlds in the Milky Way galaxy. Astronomers also believe that there is a decent chance some life forms have developed intelligence and technology. But no signals have ever been found from another civilization, a mystery called “The great silence

While SETI has long been part of popular science, METIor sending messages about extraterrestrial intelligence is less common.

I am professor of astronomy who has written extensively on the search for life in the universe. I also serve on the advisory board of a non-profit 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 do so communicate with all sorts of intelligent aliens who can be there and listen.

These efforts are like building a big fire in the woods and hoping someone will find you. But some people are wondering if it is wise to do so at all.

The Pioneer 10 spacecraft carries this sign, which describes basic information about humans and the Earth. Carl Sagan, Frank Drake, Linda Salzman Sagan, NASA Ames Research Center via WikimediaCommons

The history of METI

Early attempts at contact with extraterrestrial life were quixotic messages in a bottle.

In 1972, NASA launched the Pioneer 10 spacecraft into Jupiter sign with a linear drawing of a man and a woman and symbols that indicate where the craft originated. In 1977, NASA followed suit Gold record attached to Voyager Spaceship 1.

These spaceships – as well as their twins, Pioneer 11 and Voyager 2 – already have them all left the solar system. But in the vastness of space, the chances of these or other physical objects being discovered are fantastically minimal.

Electromagnetic radiation is a much more efficient beacon.

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

In addition to these targeted attempts to send 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 terrestrial chatter has already reached millions of stars. But there is a big difference between a focused burst of radio waves from a giant telescope and a diffuse leakage – the weak signal from a show like “I love Lucy” attenuates under the sound of radiation left over from the Big Bang shortly after leaving the solar system.

A giant spherical telescope in the shape of a plate on top of a mountain.
The new FAST telescope in China is the largest radio telescope ever created and will be used to send a message to the center of the galaxy. Ou Dongqu / Xinhua via Getty Images

Send new messages

Nearly half a century after the Arecibo announcement, two international teams of astronomers are planning new attempts to communicate with aliens. One uses a new giant radio telescope and the other chooses a new exciting target.

One of these new messages will be sent from the largest radio telescope in the world, in China, sometime in 2023. The 1640-foot (500-meter) diameter telescope will emit a series of radio pulses over a wide area of ​​the sky. These on-off pulses are like 1s and 0s of digital information.

The message is called “The lighthouse in the galaxyAnd includes prime numbers and mathematical operators, the biochemistry of life, human forms, the location of the Earth and the time stamp. The team is sending the message to a group of millions of stars near the center of the Milky Way galaxy, about 10,000 to 20,000 light-years from Earth. Although this maximizes the number of potential aliens, it means that it will be tens of thousands of years before the Earth receives a response.

The other experiment is aimed at only one 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 send a message to the star TRAPPIST-1. This star has seven planets, three of which are Earth-like worlds in the so-called Golden Hair area”- which means that they can be home to fluid and potentially life too. TRAPPIST-1 is only 39 light-years away, so it may take only 78 years to receive the message of intelligent life and Earth to receive the answer.

An image of a dense, bulbous, gas and star-filled region of space.
The center of the Milky Way galaxy may be home to intelligent life, but some researchers believe that contact with aliens is a bad idea. NASA / JPL-Caltech / ESA / CXC / STScI

Ethical issues

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

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

But there is a much deeper question. If you are lost in the woods, it is obviously a good thing to find you. When it comes to whether humanity should send a message to aliens, the answer is much less clear.

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Before he died, an iconic physicist Stephen Hawking was outspoken about the danger for contact with aliens with superior technology. He claims that they can be harmful and if given their location on Earth, they can destroy humanity. Others see no additional riskas 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 convey 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 likeThe problem with the three bodiesCixin Liu offers grim and thought-provoking perspectives on what the success of METI’s efforts might look like. The books don’t end well for humanity. If humans ever make contact in real life, I hope the aliens come in peace.

The conversation

Chris ImpeyUniversity-respected professor of astronomy, University of Arizona

This article was republished by The conversation under a Creative Commons license. Read on original article.


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