Cosmologists often speak of The Great Silence. If the prospects for extraterrestrial life are so high in the vastness of the Universe, why aren’t we hearing anything from any of our neighbors?
At the risk of sounding an unwarranted note of paranoia, it is possible our neighbors do not want us to know they are there. Stephen Hawking, before he died, sounded a warning against broadcasting our existence. He urged caution about “shouting in the jungle” before we know what may be lurking in the trees.
It’s a reasonable concern, but not, in my opinion, a particularly cogent one. Any alien life forms are far away, very far away, and they are faced with the same physical limitations as us.
But we could be pen pals, and very likely will be soon.
SETI (Search for ExtraTerrestrial Intelligence has been turning an ear skyward since 1992. You may have seen the 1997 science fiction movie starring Jodi Foster. SETI listens, but does not broadcast.
Of course, we have been broadcasting radio and television signals for over a century. Few of those signals would indicate an intelligent life form on our planet, and they are thought to be swallowed up fairly quickly by cosmic background noise.
A more targeted and sustainable signal, The Arecibo Message, was broadcast from the Arecibo Observatory in 1974. Bound for a Globular Cluster named Messier 13, it will arrive there in 25,000 years.
In 1999, The Cosmic Call was broadcast to several stars in relatively close proximity, scheduled to arrive at their destinations from 2051 to 2069.
In 2017, METI (Messaging ExtraTerrestrial Intelligence) sent a combination of math and music to GJ 273 (Luyten’s Star). It will arrive there in four years (2029), a journey of only 12 years.
In 2022, METI sent the Periodic Table, some music, and some environmental data to Trappist 1. It will arrive in 2061.
Double the sending times to arrive at the earliest possible return messages.
Breaking The Great Silence
So far, the evidence strongly supports the idea that no technology can ever send matter faster than the speed of light. The distances are so great that if any civilization is out there, we will never meet them.
Earth is our only known place with life. Maybe bacterial type of life is somewhat easy to form elsewhere, but even that guess is not yet strongly supported.
Our planet orbits a steady star in an uncrowded part of this galaxy, protected from some bombardment by outer giant planets, unlike other solar systems. In 4 billion years of brutal evolution, ice ages, hot eons, asteroid impacts, super volcanoes, and plagues, billions of species and trillions of trillions of individuals, only one species can even have this conversation. High-tech creatures appear extremely rare. We may be the only ones.
Not only do we have a 100-light-year bubble of radio and TV radiation, but we also have an 80-light-year bubble of gamma-ray flashes from nuclear explosions, which arrive before Cosmic Call and METI.
Mij Rhets says, “So far, the evidence strongly supports the idea that no technology can ever send matter faster than the speed of light.”
So far, is a good choice of words, Mij. As long as the speed of light eludes us, we cannot say whether it is or is not a universal constant. However, experimentally duplicating the speed of light may produce an answer to the question sooner than we might think.
Mij Rhets also says, “High-tech creatures appear extremely rare. We may be the only ones.” It is possible that we are among the rarest of the rare, mind-blowingly rare I would say given that the laws of physics are universal.
Mij also astutely points out that our nonsensical radio and television broadcasts are not the only evidence of our existence that have escaped the planet.