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Posted on 07/22/2025 6:02:46 AM PDT by MtnClimber
I have always been bothered by the seeming perplexity that people have about the fact that we have yet to encounter intelligent life beyond planet Earth.
It doesn't seem weird to me at all, even though I suspect life--even intelligent life--is not that uncommon in the universe.
Enrico Fermi--a great physicist from the mid-20th century-- expressed the perplexity that many people have in what has come to be known as the "Fermi Paradox."
At its most simple, the paradox is this: if the development of intelligent life is even moderately likely, why haven't we seen evidence of intelligent life elsewhere in the universe? There are so many suns, so many planets, and there has been so much time since the universe began that it is a mystery why we have seen no evidence that life exists off the Earth.
If intelligent life should be common, why don't we see any?
Astronomer Frank Drake tried to create an equation that would predict the probability of intelligent life existing beyond Earth, known as the "Drake Equation."
The Drake equation is expressed as: N = R\* \* fp \* ne \* fl \* fi \* fc \* L.
Where: N = the number of civilizations in our galaxy with which communication might be possible.
R\* = the average rate of star formation in our galaxy.
fp = the fraction of those stars with planets.
ne = the average number of planets that can potentially support life per star with planets.
fl = the fraction of planets that develop life.
fi = the fraction of life-bearing planets on which intelligent life emerges.
fc = the fraction of civilizations that develop a technology that releases detectable signals into space.
L = the average length of time for which such civilizations release detectable signals.
Disposing of the Drake Equation is pretty simple. While it has the benefit of appealing to our belief that math is authoritative, it fails to tell us anything useful because we have no idea what numbers we should put in for any of the variables. We don't even know how many stars have planets, no less habitable planets. I assume that planets are extremely common--it makes sense given how stars form--but as for "habitable planets" we have no idea. We aren't even sure what a "habitable planet" is, since we only have an N of one to study.
In other words, the Drake Equation is useless for our purposes, which leaves us with the Fermi Paradox, which seems to me to be worth thinking about.
Why HAVEN'T we seen evidence of intelligent life elsewhere in the universe?
Obviously we don't know, but I think it is unsurprising that we haven't for some very basic reasons--both because the chances of intelligent life on any one planet might be high while the chances that intelligent life develops on two relatively close planets at the same time are likely to be very low.
Human beings have only been putting out detectible signs of intelligent life on our planet for a little more than a century, and we grossly overestimate how detectible those signs would be from any appreciable distance.
Consider radio and TV broadcasts. We have been sending out such broadcasts for over a century, so any planet within a 100 light years might have detected them, right?
Probably not. If you are as old as I am, you probably put tin foil on your TV antenna trying in vain to bring in a fuzzy signal so you could watch that Star Trek rerun in black and white. When I lived in Tucson our TV had trouble deciphering a signal from a few tens of miles away--it was already snowy or worse. That's because the intensity of the signal diminishes by the "inverse square law," where the intensity of a signal (or light) reduces at a rate of 1/r². What this means is that if you double your distance from a radio or light signal the intensity you can measure is 1/4th of what it was.
So imagine picking up a radio or TV signal from 10 or 100 light years away. It's not going to happen, especially with how "noisy" space is with signals.
Then there is the issue of whether somebody is there to listen at that time. Let's say there is a habitable planet 5 light years away, and intelligent life develops there. Given that it took billions of years for intelligent life to develop here, it's reasonable to assume the same might be true elsewhere.
How likely is that there would be overlap in time? And even if you assume very long lifespans for civilizations--a questionable assumption--"long" is a relative term. If human civilization lasts a million years, that is an eyeblink compared to the lifespan of planets.
Then there is the question of density. Intelligent civilizations may be "common," but only at a galactic scale. In other words, galactically speaking there may be many civilizations--hundreds or thousands even--but the density would still likely be low. The galaxy is HUGE--it's why we use the term "astronomical" to mean really big.
To give you an idea of just how big even a solar system is, it can take light up to 7 hours just to reach Pluto from the Sun. And Pluto is in our solar system. If civilizations are scattered around the galaxy separated by hundreds of light years, they are functionally alone, even if they overlap temporally--which to me seems unlikely.
Even if we--as I hope we do--find a way to travel faster than light--and it would have to be MUCH faster than light to make interstellar travel practical--we might even land on a planet that once had intelligent life and never see any evidence it was there unless it died out quite recently in the lifespan of the planet.
For that matter, it could even be that there have been prior civilizations on Earth--non-human, presumably--and all the evidence has been wiped out due to the ravages of time.
It's even remotely possible that human civilizations have risen and fallen, leaving behind little to no evidence that we could discover. I have no reason to believe that has happened, but I would not be gobsmacked if it had.
Given all the variables, it strikes me as utterly unsurprising that we have yet to discover evidence of other intelligent life in the universe. Not because I think there is none--I share Fermi's belief that intelligent life is pretty common in the universe, and it would be a crying shame if it wasn't. The universe is a wondrous creation.
But life at the same time, nearly the same place, and detectible using ordinary means? That would be extraordinary.
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It seems unlikely that we could pick up a signal from any great distance even within our own galaxy.
Ping
What percentage of earth’s existence did it contain intelligent life?
why haven’t we seen evidence of intelligent life elsewhere in the universe?
We have. When they appear we label them Angels and Devils. Not only in the Judeo tradition, but in many cultures of the past there have been tales of “non-human” intelligent life forms.
It is our own pride that prevents honest discussion.
I believe this value is typically wildly overestimated.
One Ping and one ping only, please!...............
“...Why haven’t we seen evidence of intelligent life elsewhere in the universe?...”
Because we haven’t been anywhere.....
Maybe we shouldn’t want to be found…..
A superior intelligence might not be impressed by our “ civilization”
Ham radios. Nuff said. 😂👍
A superior civilization might not use radio communications for very long any more than they would use smoke signals.
The percentage of Earth’s existence that we have been generating radio waves is 100 years divided by 4.5 billion years. That is 0.0000000022%.
fL, fI and L are what are so unknowable about the Drake equation. And for all we know, fL could be 1x10^-100,000,000,000. The circular reasoning supporting the notion that fL is some non-infinitessimal number is incredible. And the misreporting just as much.
Do you realize when they report that they’ve discovered conditions under which it would be possible for an amino acid to form, it’s not even the right amino acid? And so what? To suggest that this makes life inevitable and therefore common is like saying that the fact that a mark on a stone resembles a letter means it’s capable that with an infinite number of marks possible over an infinite amount of time (the “monkeys typing” argument), it’s inevitable that the complete, unabridged works of Shakespeare will spontaneously emerge. Oh, except the letter that it looks a little bit like is epsilon, not a letter in the English language.
Oh, and that “monkey argument?” That says that if you have an infinite number of monkeys hitting random keys for an infinite amount of time, they’ll eventually type the entire works of Shakespeare, verbatim, consecutively, so anything could happen to exist by chance, no matter how complex. It’s based on false premises.
There’s not an infinite amount of time, not an infinite amount of space, and not an infinite number of universes as the argument presumes. There’s no evidence for a multiverse (which is not to say there’s no evidence for multiple dimensions, we just don’t know whether those dimensions are sparse or dense). There’s strong evidence against the notion of our universe pulsing. There’s a finite minimum size (Planck’s constant), and a finite size of the universe. The scale of these numbers is literally unimaginable, but nothing compared to 26^5,000,000, which is how many keystrokes you’d have to type to accidentally type Shakespeare. (Actually, more, because there are more than 26 keys.)
In fact, infinity does not exist, except possibly the forward direction of time. Our notion of infinity stems from its use in Calculus, but that use is allegorical. We substitute “negligibly small” or “infinitely small,” and we get Alice in Wonderland. (Literally: Lewis Carroll was a Christian minister who recognized the theological danger posed by the methods used to teach Calculus and wrote Alice in Wonderland to warn against it. There are, by the way, ways of teaching calculus without using the absurdities of infinity.)
See, 1 divided by infinity doesn’t equal zero. There are tons of mathematical absurdities created by this notion, such as infinity PLUS 1/infinity can be proven to equal -1. The fact that is “obviously” not true doesn’t disprove the math used to conclude that, it disproves the way infinity is used in arithmetic.
“Not only in the Judeo tradition, but in many cultures of the past there have been tales of “non-human” intelligent life forms.”
Exactly right. And they all came from “the Heavens”.
There is an eternal realm that is both spiritual and invisible. Jesus said, “God is spirit.” The spiritual rules over the visible.
The spiritual realm has beings (angels, demons - fallen angels) which can apparently at times become visible.
Why can we not explain this? Because we are so unaware of the spiritual realm. Jesus was totally aware of it - He came from it, and reigns now over both the visible (temporal) world and the invisible (eternal) realms.
God sets the universe before us as something that declares - by its un-measurable dimension - His glory and power. He created it in an instant by speaking a word - and it came into being.
We are fools to not see the hand of God in His visible, created universe.
This is based on a misconception anyhow. It assumes we will find it far away. When the reality is they are right here now and have been for thousands if not hundreds of thousands of years.
All was created by Him and for Him. John 1, Colossians 1. Earth is unique in that it was created for man - who was made “in His image”.
Both earth and man were created for what Ephesians calls “the eternal purpose”, which is to display and glorify the Lord Jesus Christ forever. For that purpose, Jesus took on flesh and became a Man - to go to the cross and die for man’s sins, and to deal a death blow (yet to be seen) over both death and sin.
He was raised from the dead to establish forever that He is Lord over both heaven and earth - forever!
Look into the rare earth hypothesis.
In a great number of solar systems that we observe, a large gas giant like Saturn will end up “crashing” down through the solar system toward the star taking out all of the smaller rocky planets between it and it’s eventual final orbit. Our solar system just so happens to have 2 of them right next to each other to prevent this “crashing” down effect and keep them in a stable orbit far out from the sun. They also protect the inner planets from debris coming in from outside the solar system.
The earth has a comparatively enormous moon to similar planets as the result of a previous impact. In addition to protecting us from impacts, it more importantly creates tides. Tidal pools are likely where the first life began. Without the ancient impact and resulting huge moon creating tides, there may be no life on earth.
These both seem like pretty unique circumstances.
I don’t think it is a “gimme” that there is life all over the universe. In fact, I might be inclined to believe that we are the only place.
I think the Drake Equation is misunderstood.
It’s NOT an equation in the sense that it is solvable.
It’s only an illustration of the various conditions we would need to say without doubt how many extraterrestrial civilizations might exist and our probability of discoveing them.
As our technology advances, we are able to estimate some of the parameters in the equation, such as the number of stars that have planetary systems and the number of those systems capable of supporting life.
Over the last years, great advances have been made in the detection of extraterrestrial planets around stars - when I was growing up, such detection was thought to be impossible.
But astrometry has progressed. It is possible now to detect the *gravitational* effect of a large planet on a star’s motion.
It is also possible to detect the small, small “shadow” of a planet passing in front of a star.
And more recently, the we are able to detect certain chemicals in planet’s atmospheres that indicate the chemicals are formed by living organisms.
So one, by one, we are able to arrive at values for the various components of Drake’s equation. But it will take actual exploration to find the true value of N.
“to boldly go where no man has gone before.”
Some few have been listening at the "water hole," using the red shift features a filter, and hear -- nothing.
One may add, "as yet." But to what effect? We grossly overestimate ourselves.
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