On average, any star in the sky has one or two planets and with billions of stars in the Milky Way, its easy to wonder where all of the other intelligent life is. In 1950, Dr. Enrico Fermi posited this question simply, asking, "Where is everybody?" which was later coined the Fermi Paradox in 1975. Matthew Williams, a writer and science communicator, investigated the paradox and its challenges in a blog series, "Beyond Fermi's Paradox" in Universe Today.
If we did hear from spacefaring alien lifeforms, how would we react?
Subscribe and join us weekly for astronomical facts and interesting science.
If you have questions you would like answered on Astro Brief, email them to Dr. Mike Reed at mikereed@missouristate.edu.
Astro Brief is a podcast collaboration between KSMU, the Missouri Space Grant, and MSU's Department of Physics, Astronomy and Materials Science. Hosted by Dr. Mike Reed, Astro Brief focuses on astronomical events, the field of astronomy, and astronomy-related guests. It airs Thursdays at 9:45 am on KSMU.
Transcript
One of the big, outstanding questions for humanity is — Are we alone?
In the 100-level General Education Astronomy courses I teach, we talk about how most stars have planets and estimates on rocky planets in the habitable zone is in the tens of millions in our galaxy alone. And much later in the course we talk about the Drake and Seager equations and the Fermi Paradox. Then when I survey these — mostly non-science majors — on whether or not alien life exists, more than 90% typically answer that it does. That doesn't mean intelligent life, just life.
Much earlier in my courses, when we're talking about Mars, I ask what it would mean to humanity if we discovered life there. Typically the response is pretty meh, nothing substantial. Obviously it wouldn't be intelligent life, just microbial, and that doesn't really seem to have much impact. But I found a series of blog posts by Matthew Williams on Universe Today titled, "Beyond Fermi's Paradox". And this particular one was called, "What if We Make Contact?"
Let's set that stage.
In the 1950s, at our Los Alamos National Laboratory, physicist Enrico Fermi was having lunch with some colleagues who were talking about aliens when Fermi asked, ""Where is everybody?" This has become known as the Fermi Paradox.
But why does asking this question make a paradox?
While our solar system is 4.6 billion years old based on radiometric dating, the disk of our galaxy is 10 billion years old. The oldest stars in our galaxy — with presumably the oldest solar systems in our galaxy — are 12 billion years old. Our universe is nearly 14 billion years old. The paradox is, if our planet is less than half the age of our local galaxy, and less than one-third the age of our universe, why should we be the first? Where are the other spacefaring alien civilizations, and why haven't they made contact with us?
Certainly a big issue is, how do we know if we receive a signal from space?
The first step is to filter out noise, mostly made by human signals. The second step is to rule out space stuff that is already known, like pulsars. The first pulsar detected, which was a consistent radio pinging at about one second, was initially thought to be an alien communication. Later it was found to be a spinning neutron star.
The third step is to use a second telescope to observe the signal to rule out instrumentation effects. Of course, that would mean the signal needs to continue long enough to get a second telescope on it. And the last step is to analyze the pattern to see if it has structured language or mathematical patterns. Nature tends to be random, or to follow strict repeating physical laws. When we intentionally send signals to space — which we have — we begin with pulses indicating prime numbers — a very non-random process.
Okay, so let's say we receive a signal, the steps have been carried out, and we now know it's an alien society — then what?
Guides were established in 1989 and updated between 2022 and 2025. First and foremost are provisions to ensure public communication so that no government can cover it up. This includes alerting the UN Secretary General, the UN Committee on the Peaceful Uses of Outer Space, the UN Office of Outer Space Affairs, the International Academy of Astronautics, and the International Astronomical Union, among others. Mr. Williams states that a confirmed detection of a signal from an alien civilization would be the "...single greatest event in human history...".
Is that true?
The question of are we alone would be answered forever, since it only has to be answered once. The Rio scale was adopted in 2002 and while it is about the detection of signals, it has some interesting features. Those include the distance to the source — which remember could be hundreds to thousands of light years away, the prospect of communicating with the source, remembering that signals travel only at the speed of light. So a source 10 light years away would receive our response 20 years after they sent their signal.
The last factor of their equation is how likely it is that the aliens are aware of us. We have inadvertently been sending signals into space for over a hundred years. Perhaps aliens' first notice of us will be episodes of Gilligan's Island, like in Galaxy Quest. Okay, so let's say we receive a signal and it says, "Hello humanity, we hear you.".
Then what?
Do we respond in kind, hoping to exchange technologies? Do we prepare for armageddon? Or do we shrug our shoulders and go, "Meh".