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The Search for Extraterrestrial Intelligence
The great Austrian scientist Nikola Tesla (1856-1943) thought he had detected a signal from some life form on Mars. That was in 1899 and Mr. Tesla was wrong, but other famous scientists such as Lord Kelvin and Guglielmo Marconi also tried to make contact with non-existent Martians.
Today, the hunt for other civilizations is sophisticated and well-funded. In 2015, the Russian billionaire Yuri Milner gave $100 million to a program called Breakthrough Initiatives, which is part of the Search for Extraterrestrial Intelligence (SETI).
If you are trying to find extraterrestrial life, what do you look for? Here we go to the work of two Cornell University physicists, Philip Morrison and Guiseppe Cocconi.
The National Geographic reports that in the early 1960s the two “tried to figure out how a distant extraterrestrial civilization, if one existed, might try to contact others in the Universe.” Their first assumption was that aliens would send a radio signal and the message had to make sense to an unknown society that probably spoke an entirely different language.
The physicists decided intelligent aliens would send a signal that mimicked the electromagnetic frequency of something common in the Universe. And, what better chemical signature to send than the most abundant element – hydrogen? That was what was picked up in the Wow Signal.
An observatory at Ohio State University picked up a signal in August 1977. A project volunteer, Jerry Ehman, was reviewing printouts of signals found by a radio telescope when he spotted a sequence “6EQUJ5.” For people in the SETI business that seems to be a Eureka moment and Mr. Ehman wrote “Wow” next to the letters and numbers. It looked like a message from another civilization and colleagues agreed with that assumption.
Parts of the signal were 30 times more powerful than the background noise of deep space. But, as National Geographic reports “More than three decades later, the Wow Signal, as it has come to be known to SETI researchers, remains both the first and best potential evidence of communication from extraterrestrials, and one of the most perplexing mysteries in science.”
Despite masses of investigation no one has been able to prove that the Wow Signal was sent by an alien civilization.
Are they Looking for us?
What about the other direction? Is someone out there listening for evidence that we exist? The Planetary Society says “Humans have been broadcasting radio waves into deep space for about a hundred years now, since the days of Marconi. That, of course, means there is an ever-expanding bubble announcing humanity’s presence to anyone listening in the Milky Way.”
Tim Moynihan (Wired, July 2015) writes that “Radio waves travel at the speed of light, so if you were one light year away from Earth - that’s 5.9 trillion miles - you’d hear broadcasts from a year ago.”
WWJ is recognized as the first radio broadcaster, going on the air as Detroit News Radiophone on August 20, 1920. Its first programs have now reached 96 light years out into space. But, the centre of our galaxy, the Milky Way, is 25,000 light years from Earth.
So, our radio signals have only reached a tiny corner of deep space, although NASA estimates there are 1,500 planets within 50 light years of Earth. However, the radio signals are likely so weak that listeners would need better equipment than anything we have on Earth to detect them.
Doubts about other Life
Life evolved on Earth quite quickly after the planet cooled. This fact is used to prop up the argument that such an occurrence must be common, so there must be life elsewhere in the Universe. But, that’s an assumption, not a scientifically provable fact.
Joshua Winn is an associate professor of physics at the Massachusetts Institute of Technology. He says “… with a sample of only one life-bearing planet, one cannot even get a ballpark estimate of the abundance of life in the Universe.”
This echoes the findings of David Spiegel of Princeton University. He says “using evidence of our own existence doesn’t show anything other than that we are here.”
On the other hand, recently scientists have discovered planets out there in the so-called Goldilocks zone. This is where the planet is not too close to and not too far away from its star so it’s in an area where liquid water can form. The existence of liquid water is essential for the creation of life as we understand it.
The National Aeronautics and Space Administration (NASA) has been using its Kepler Space Telescope to find possible life-sustaining planets. By March 2016, NASA had identified more than 2,000 so-called Kepler exoplanets, places where conditions could be hospitable for the creation of life. New ones are being discovered almost daily.
The Kepler Telescope so far has only looked at 1/400th of the Milky Way. An estimated 50 billion planets exist in the Milky Way; about 500 million of these are predicted to be in the Goldilocks zone. NASA lifts the numbers even higher: “Our Milky Way galaxy contains a minimum of 100 billion planets …”
But, even larger quantities exist as outlined by Daily Galaxy: “Astronomers estimate that there are 100 billion galaxies in the Universe. If you want to extrapolate those numbers, that means there are around 50,000,000,000,000,000,000 (50 quintillion) potentially habitable planets in the Universe.”
Arthur C. Clarke was a physicist and the author of 2001: A Space Odyssey. He wrote that “The idea that we are the only intelligent creatures in a cosmos of a hundred billion galaxies is so preposterous that there are very few astronomers today who would take it seriously.”
Stephen Kane, with NASA’s Exoplanet Science Institute at Caltech agrees. He says “Results from the three main techniques of planet detection … are rapidly converging to a common result: Not only are planets common in the galaxy … This is encouraging news for investigations into habitable planets.”
The Fermi Paradox
The Italian Enrico Fermi was a brilliant physicist. While having lunch with an equally talented scientist, Edward Teller, Mr. Fermi asked “Where is everybody?” This question, posed in 1950, sparked a discussion about the absence of alien life forms on Earth. Out of this came what’s known as the “Fermi Paradox.”
Human civilization is very young in the context of the age of the Universe. There have been almost countless chances for life to develop on other planets in the Milky Way; and, they would have had a head start on us in the order of billions of years. That means their technology would be way ahead of ours and the galaxy ought to be teeming with spaceships.
But, asks Fermi, “Where is everybody?”
No aliens have contacted us and we have found no sign of them.
“Sometimes I think the surest sign that intelligent life exists elsewhere in the Universe is that none of it has tried to contact us.”
Calvin and Hobbes
Astrophysicist Neil DeGrasse Tyson says the closest genetic relative to humans is the chimpanzee. “If you look at the genetic code it’s nearly all identical, except for maybe one-and-a-half percent.”
Chimpanzees cannot learn trigonometry, the names of continents, or Mandarin. Yet, there’s only that small difference in genetic coding between us and chimps.
Now, says Dr. Tyson “Imagine a creature with the same increment in intelligence above us as that we are compared with the chimpanzee.”
The intelligence gulf between us and them would be as deep and wide as it is between us and chimpanzees. While toddlers of our species were learning the ABCs, their toddlers would be handling calculus.
“By the time they’re in their teens they would be looking as Isaac Newton, Galileo, Copernicus, and Einstein as drooling, doddering fools, the same way we look at chimpanzees that figured out how to put a stick in a termite mound to pull out the termites.”
Where this is all going is that a super intelligent life form might have no interest in us. Perhaps, they have found us and decided we are too primitive to be bothered with.
“Extent of Human Radio Broadcasts.” The Planetary Society, undated.
“Stunning Sim Shows how Far Hit Songs Have Traveled in Space.” Tim Moynihan, Wired, July 14, 2015.
“Expectation of Extraterrestrial Life Built more on Optimism than Evidence, Study Finds.” Morgan Kelly, Princeton University, April 26, 2012.
“What is the Wow! Signal?” Patrick J. Kiger, National Geographic, June 21, 2012.
“Ignoring 500 Billion Galaxies: Mathematics vs. Common Sense in the Debate About the Probability of Extraterrestrial Life.” The Daily Galaxy, February 23, 2012.
“The Milky Way Contains at Least 100 Billion Planets According to Survey.” Hubblesite, January 11, 2012.