Scientists try to signal aliens

In this 30-second exhibit, a meteor streaks across the sky during the annual Perseid meteor shower, Wednesday, August 11, 2021, in Spruce Knob, West Virginia.

In this 30-second exhibit, a meteor streaks across the sky during the annual Perseid meteor shower, Wednesday, August 11, 2021, in Spruce Knob, West Virginia.
Photo: NASA/Bill Ingalls

Two teams of astronomers prepare to send a direct message into space to signal other intelligent life. The message they send boils down to: HHey ! We are here ! We know basic math! It could be decades, if not centuries, before we hear a response, if there’s anything out there. It could be a very good thing.

Ars-Technica has an interesting story about Extraterrestrial Intelligence Messaging, or METI, the more direct communication version of SETI, which passively listens in for broadcasts from beyond the stars. So far SETI hasn’t found anything.

Although you may have heard that we’ve been sending broadcasts to the stars for 100 years now, radio and television waves defuse quite quickly under the background radiation of the universe. The three tiny spacecraft we sent beyond our solar system have an infinitesimal chance of being found in the vastness of space. Instead of hoping to be found or listening to other civilizations, two teams working on separate projects will use electromagnetic radiation to communicate directly with points in our galaxy that show promise for intelligent life:

One of these new messages will be sent from the the largest radio telescope in the world, in China, around 2023. The telescope, 1,640 feet (500 meters) in diameter, will emit a series of radio pulses across a wide swath of sky. These on-off pulses are like the 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 Earth, and a timestamp. The team sends 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. While this maximizes the pool of potential extraterrestrials, it means it will be tens of thousands of years before Earth receives a response.

The other attempt targets 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 “Goldilocks Zone”“- meaning they could harbor liquid and potentially life too. TRAPPIST-1 is only 39 light years away from us, so it could take intelligent life 78 years to get the message and to Earth to get the answer.

Scientists are trying to solve what is called “The great silence.” For 70 years, we have been looking for signs of other advanced civilizations among the stars. Despite hundreds of millions of habitable worlds in our galaxy alone, we have found no evidence of life, let alone intelligent life, outside of planet Earth. This is the Fermi paradox; there should be civilizations everywhere, so where is everyone?

There are quite a few possible explanations. Civilizations reach turning points where they prosper or self-destruct, and none survived; we are too far off the beaten track for space civilizations; we were visited but did not notice; we do not use enough similar technologies to communicate; and space travel is simply impossible. But my favorite theory is the dark forest theory, which refers to a series of books called The three-body problem from Chinese science fiction author Liu Cixin:

The universe is a dark forest. Every civilization is an armed hunter stalking through the trees like a ghost, gently pushing aside the branches that block the way and trying to walk quietly. Even breathing is done carefully. The hunter must be careful, because everywhere in the forest are stealth hunters like him. If he finds another life – another hunter, an angel or a demon, a delicate infant to a tottering old man, a fairy or a demigod – there is only one thing he can do: open fire and eliminate them.

Maybe everyone is quiet because something big and predatory is lurking in our dark forest. Maybe shouting to the sky is the exact opposite of what we should be doing. A few years before his death, Stephen Hawkings told a CuriosityStream broadcast about attempts to contact aliens, according to

“One day we might receive a signal from a planet like this,” Hawking says in the documentary, referring to a potentially habitable alien world known as Gliese 832c. “But we have to be wary of responding. Meeting an advanced civilization could be like Native Americans meeting Columbus. It didn’t go so well.

me, for my part, welcome our new future alien lords.


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