By Dr. Gary Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
This is the third article in a four-part series discussing the probabilities of extraterrestrial life elsewhere in the Milky Way galaxy.
In the first article in this series, I reviewed the Drake Equation and its suggestion that the galaxy could have other intelligent life. In the second article, I examined the Fermi Paradox, which seems to imply that the lack of extraterrestrial contact at this point in the galaxy’s evolution cannot be reconciled with what we should expect to see according to Drake. In this article, I will discuss the efforts being made to detect the presence of extraterrestrial life.
SETI and the Constant Search for Other Life in the Universe
In an effort to reconcile the claims of Fermi, Drake, and a host of other astronomical theorists throughout human history, mankind has made some of its first planned and scientifically sound efforts at rooting out whether intelligent life does, in fact, exist elsewhere in the Milky Way galaxy. Collectively, these efforts are known as the Search for Extraterrestrial Intelligence (SETI, which is pronounced “seh-tee.”)
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SETI, in its current form, was first established by Frank Drake back in 1960 — around the same time that he published his “Drake Equation”. Today, SETI enjoys global participation and consists of arrays of radio telescopes that listen for signals from intelligent life elsewhere in the universe.
Astrophysicists Carl Sagan, Bruce Murray and Louis Friedman founded the Planetary Society as a support organization for SETI. In fact, public interest in these efforts has grown over the years.
How Would Extraterrestrial Life Communicate with Earth’s Inhabitants?
An obvious and fundamental problem with talking to alien beings is that we really have no idea how such “aliens” would communicate. On our own planet, animals and other living things communicate in a number of different ways that include the use of all five human senses and a few others that we do not possess. Suffice it to say that speculating about default communication modes for extraterrestrials is little more than an exercise in futility.
Even if we knew, for example, that another lifeform communicated in a spoken language or some form of sound, there is no guarantee that the sounds would be within the human range of audible hearing. Ordinary dogs here on Earth can hear much higher frequency sounds than we can, so it would be naive to assume that aliens could hear us even if we tried to speak to them.
Let us even go so far as to assume that extraterrestrial life could hear us, though. E.T. still isn’t going to speak English.
So what language would we use? And how could we decode it in order to understand one another?
SETI experts have effectively circumvented all of these problems through the use of radio astronomy. All matter emits radio waves based on its temperature.
Hydrogen, for example, is the most abundant element in the universe, and it emits radio waves at a frequency of 1,420 megahertz (MHz). The beauty of this fact is that hydrogen’s frequency is the same throughout the universe.
So if a species of alien life has developed radio astronomy, then it knows the frequency of hydrogen. And this physical constant provides a baseline for mutual communication between different life forms.
What SETI does, essentially, is listen for radio wave signals from deep space. It looks for patterns or phenomena that could only be the product of intelligent design.
For example, in the science fiction novel “Contact” by Carl Sagan (also a 1997 movie starring Jodie Foster), SETI astronomers discovered pulses of radio waves in groups equivalent to the first few prime numbers — 1, 3, 5, 7, 11, 13 and so on. This indicated to them that the signal could only be from an intelligent manufacturer because there are no known natural phenomena that would produce radio signals in such a pattern.
Could Extraterrestrial Life Be Hostile to Earth?
Some theorists are concerned that if intelligent life does indeed exist elsewhere in the galaxy, it may not be friendly. Consequently, making Earth’s presence known could be a risky decision.
On that point, it is important to note that SETI only listens; it does not send any signals. So while we might be able to detect extraterrestrials using SETI, SETI does not do anything that would allow them to detect us.
However, this concern is also somewhat moot because manmade radio transmissions — from radios, TVs or satellites — have been radiating out into space at the speed of light since the dawn of human radio technology. Any intelligent life within 100 light-years or so of Earth and receiving these signals might already be aware of our presence anyway.
It is also worth noting that the ‘listening only’ policy of SETI is argued by some theorists as an explanation for the Fermi Paradox. In other words, if all intelligent life in the universe is following a similar listening-only policy — and not transmitting for reasons of caution and self-protection — then civilizations might cohabitate a galaxy without ever knowing of each other.
Notwithstanding the SETI search efforts and the lack of “contact” so far, some experts believe that extraterrestrial life is plentiful, so much so that such life might even exist right here in our own solar system. In the last part of this article series, we’ll look at some of the most likely places life might be hiding on the planets and moons of Sol.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.