When a person gets lost in the wild, they have two choices. They can search for civilization or be easily identified by making a fire or writing HELP in large letters. For scientists interested in the question of whether intelligent aliens exist, the possibilities are similar.
For over 70 years, astronomers have searched for radio or optical signals from other civilizations in search of extraterrestrial intelligence SETI. Most scientists are confident that life exists on many of them 300 million potentially habitable worlds in the Milky Way. Astronomers also believe there is one good chance some life forms have evolved intelligence and technology. However, signals from another civilization have never been detected, a mystery dubbed “The great silence.”
While SETI has long been a part of mainstream science, METIor the transmission of extraterrestrial intelligence, was less common.
I am a 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 Designing messages to send to extraterrestrial civilizations.
In the coming months, two teams of astronomers will try to send messages into space communicate with intelligent aliens who can out there listening.
These efforts are like making a big campfire in the woods and hoping someone finds you. But some people wonder if it’s wise to do it at all.
The story of METI
Early attempts to contact life beyond Earth were unworldly messages in a bottle.
In 1972, NASA launched the Pioneer 10 spacecraft toward Jupiter with a Plaque with a line drawing of a man and a woman and symbols show where the craft originated. In 1977 NASA followed with the famous Golden record attached to Starship Voyager 1.
These spaceships – as well as their siblings Pioneer 11 and Voyager 2 – now have everyone left the solar system. But in the immensity of space, the chances of finding these or any other physical objects are fantastically slim.
Electromagnetic radiation is a much more powerful beacon.
Astronomers broadcast the first radio message intended for extraterrestrial ears Arecibo Observatory in Puerto Rico in 1974. The Series of 1 and 0 was designed to convey simple information about humanity and biology and was sent to the globular cluster M13. Since M13 is 25,000 light years away, don’t hold your breath for an answer.
In addition to these deliberate attempts to send a message to extraterrestrials, wayward signals from television and radio broadcasts have been seeping into space for nearly a century. This ever-expanding bubble of terrestrial chatter has already reached millions of stars. But there’s a big difference between a focused blast of radio waves from a giant telescope and a diffuse leak — the faint one signal from a show like i love lucy fades beneath the hum of radiation left over from the Big Bang just after it left the solar system.
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