The Australia Telescope array near Narrabri, New South Wales, with Mercury, Venus, and the Moon all is the same stretch of sky. It's the 50th anniversary of attempts to search for signs of extraterrestrial intelligence.
Credit: Graeme L. White and Glen Cozens/James Cook University
Two young physicists at Cornell University in upstate New York, Philip Morrison and Giuseppe Cocconi, had long been interested in gamma rays. One spring day in 1959, Cocconi posed an intriguing question: wouldn’t gamma rays be perfect for communication between the stars?
The discussion that followed led to a two-page article in the British journal Nature entitled “Searching for interstellar communications”. Sandwiched between a paper on the electronic prediction of swarming in bees and one on metabolic changes induced in red blood cells by X-rays, the duo argued that if advanced extraterrestrial civilisations existed, and wanted to communicate, they would likely use radio.
They proposed a search of nearby Sun-like stars for signals at or near the 21-centimetre wavelength of neutral hydrogen, a band of frequencies between 1,420 MHz and 1,640 MHz.
It’s a quiet region between two notable frequencies – the hydrogen line and the strongest hydroxyl spectral line, which combined yield water, considered essential for life. Hydrogen is also the most common element in the universe. Thus was born, 50 years ago, the search for extraterrestrial intelligence, or SETI.
Throughout history, people have speculated about other worlds and life elsewhere. Italian astronomer Giordano Bruno was burnt at the stake in 1600 not only for suggesting Earth orbited the Sun, but that there were other inhabited worlds in the universe.
German philosopher Immanuel Kant was convinced of this, as was the French nobleman and mathematician the Marquis de Laplace. As Teng Mu, a Chinese scholar wrote 3,000 years ago: “How unreasonable it would be to suppose that, besides the earth and the sky we can see, there are no other skies and no other earths?”
SETI is like a search for a needle in a colossal haystack. As Jill Tarter of the SETI Institute has said, it’s not only unimaginably large, but nine-dimensional: three of space, one of time, two of polarisation (or perhaps photon rotation/twist), plus frequency, modulation, and sensitivity (a combination of transmitter power and distance).
“And that’s only the haystack we can describe with what we know about physics and technology in the 21st century, and from our terrestrial and inescapably anthropocentric vantage point,” she says.
Question of Extraterrestrial Advanced Species & Contact
I subscribe to the expectation that life is common in our galaxy, but that highly evolved, sizable terrestrial plant and animal life as is present on Earth is less common and that technologically advanced ET species, as with humans on Earth, are least common, but mathematically, on the whole, are present in the planetary systems of our galaxy, although in low ratios, yet nevertheless in the hundreds of thousands to tens of millions or more among the estimated 200 billion to 300 billion stars in our galaxy. I imagine it to be a stupendous and lucky scientific and technological feat to happen upon and make contact with technologically advanced technological ET species, but regard the effort for this to be a commendable and worthy, and, indeed, a most worthwhile effort for a contact of a potentially unparalleled El dorado of scientific knowledge gains to scientific humanity and furtherance of a benevolent human civilization. I am hopeful for METI and SETI. The history of human achievement counsels us that tenacity and perseverance, with flexible intellect, can achieve whatever is possible.
Bruno: A Martyr for Science?
While it has no direct bearing on the article, according to John Gribbin's 'Science, A History', it is a common misconception that Bruno was burned at the stake for his scientific views. Whilst obviously there is no good reason for such an execution, Bruno was burned because he was a heretic: believing that Jesus was not incarnate of God, and for the practice of occult magic.
Why seek and find?
The real reason behind our pursuit of life on other planets is simply a desire to conquer and enslave. Men cannot live in peace on their own little piece of the universe, what in the world makes you think we will get along with 'others' from our there. Get a grip man! Stop all financing of projects that is wasted outside of our own little world and spend it on educational facilities, hospitals and food for the needy. As for all you slackers hiding at Cosmos- go get a real job and do some worthy with your time.
Why seek indeed
as much as i am all for the idea ( finding Alien life ) you DO have bloody good point i have to say.
Why not?
Don't overestimate the impact of sinking everything we have into educational facilities, hospitals and food. Besides, the proportion of investment we spend in SETI or any other space program is miniscule compared to defense programs, intelligence programs, public works and health already.
Treat what you will the desire to find life - I however think that the very act of trying to find life makes us a better people. Call me a romantic if you like.