In general, solutions to Fermi’s paradox come down to:

  • Life is difficult to start and to evolve to an intelligent and technologically advanced stage and we’re the only one in the galaxy.
  • Advanced civilizations destroy themselves on short timescales.

As the revised Drake equation solution (N<<1) shows, it seems that hopefuly, the first solution is the answer.

Here is a list of the various assumptions along with notes pointing to related problems and contradictions.

They are here unobserved

They were here and they left material evidence:

UFO’s, alien artifacts, ancient astronauts. Problem: evidence for aliens is non-existent.

Zoo scenario:

The aliens are here and they are keeping us in a well designed zoo (cut off from all contact) or there is an treaty preventing contact with young races. Problem: this scenario can’t be tested. Only one ET could break the embargo.

They are us:

Humans are the descendents of previous alien civilizations. Problem: where are the original aliens? where are all the other alien civilizations?

They exist but…

They didn’t have enough time to reach us:

The speed of light slows communications and makes space travel too long. Extraterrestrial’s messages may not have reached us yet. Problem: the galaxy exist for billions of years, even if one ET civilization formed a few million years before us, the galaxy would be already filled with Bracewell-Von Neumann probes.

They are sending signals, but we do not know how to listen:

The galaxy is filled with killer robots looking for signals. ET is keeping low. Problem: no evidence of berserkers coming after us.

They have no desire to communicate:

ET has no interest in communicating with lesser intelligences. Problem: with millions of possible civilizations, some of the extraterrestrial ones would be interested in our species.


Civilizations only have a limited lifetime, they are all dead.
Dangerous particle physics
Nanobots -> the gray goo problem

They developed different mathematics:

Mathematics is the universal language, but humans may have a unique system of mathematics that ET cannot understand. Problem: then where are those incomprehensible signals?

They do not exist because…

We are the first in the galaxy:

Life is new to the galaxy and evolution takes time. We are the first intelligent civilization. Problem: the Sun being an average star, if other stars formed a million years ahead of us, then they would be a million years ahead of us technologically speaking.

Planets with the right conditions are rare:

Habitable zones, proper orbit for liquid water are rare
The galaxy is a dangerous place (asteroid impacts, gamma-ray bursters, etc)
The Earth/Moon system is unique (large tides needed for molecular evolution)
Life is rare

Life’s genesis is rare:

Intelligence and tool-making is rare
Language is unique mankind
Technology and science is not inevitable


What do you think?

Leave us your thoughts below!



Possible Answers to the Fermi Paradox SKU UPC Model

RF advertising

Oct 22, 2018 by Del Arno

I think it is disadvantageous for an advanced civilization to advertise its presence. the reason we are is because we are nascent and nieve. I believe the universe is imperialist for resources we don't yet understand.

I loosely hypothesize genetic information or life itself as a source of information and alliances/cooperation once we become a player.

just as a babies immune system begins to develop in the womb, a civilization must learn to become stealth to curb external interference. What advantage would a subordinate intelligence have in advertising? what civilization isn't subordinate in a universe of infinite possibilities?


Oct 21, 2018 by Sreehari S

I think the advanced civilizations gradually loose interest in exploring new worlds and even their urge to survive and reproduce. They might have just died off or they put themselves into a state of eternal pleasure.

Not everything has to happen right now

Sep 06, 2018 by Marty Johncox

People discussing this issue commonly fail to appreciate the immensity of time. It's possible aliens recently existed and even visited us, or will find us very soon (say, 100 million years either way). Earth has had sentient life on it for just the last 1/30,000th of its existence, so the chance of aliens coexisting with us and then visiting us is vanishingly small. It's entirely possible that life is so rare - and intelligent life rarer still - that it never coexists and there may be vast periods of time where there is no intelligent life anywhere in the universe. Look at it this way: The expected lifespan of the universe is 100 trillion years (100,000 billion). Just 14/100,000ths of the way through that and we know intelligent life emerged (us) - holy cow, that was fast! Suppose 1 million intelligent species came and went during those 100 trillion years. Sounds like a lot, right? That would come out to 1 intelligent species every 100 million years. By comparison, dinosaurs died out about 65 million years ago. Life and intelligent life may be very common in the timescale of the universe, but nonexistent during the fleeting existence of any single solar system. It's arrogant to expect the universe to operate on our teensy-tiny timescale.

We are they

Sep 02, 2018 by Dave

If an alien civilization wanted to go to other planets, they wouldnt send space ships, they would send dna that was robust enough to germinate on other worlds. Eventually this dna would create sentient beings if conditions permitted. These sentient beings would want to connect with the alien worlds.. just as we do. And we will send out dna, in some robust form, perhaps 10000 moles, in all directions in the sky, to settle on t0 other worlds, and create environments suitable to advanced life again.

If we were motivated, we could do this now and fulfill our destiny.


Aug 06, 2018 by Okay

"ET has no interest in communicating with lesser intelligences. Problem: with millions of possible civilizations, some of the extraterrestrial ones would be interested in our species."

This "problem" is an example of anthropocentrism. Shocking for some to consider, but even if there are millions of interstellar alien civilizations, they would have within their power ways to observe and learn about our planet without interfering with the course life.

Time Distance Commitment

Jul 10, 2018 by Shannon

Nothing travels faster than the speed of light, except the universe's expansion. The time it would take to physically travel to Earth would be an impossibility, even if travelers would be willing to commit to it and their offspring for generations. Unless there is a way to travel faster than light, radio waves would have too far to travel to reach us.

Additionally, technology took millions of years to be developed from the origin of hominids. I imagine over prototypes still evolving as well. Sadly, I think technology ultimately destabilizes civilizations and anyone that was advanced enough to contact us, probably no longer exists.


Jun 17, 2018 by Torbjorn Berglund

If we assume that the time a "Tech civilisation" uses electromagnetic radiation for communícation to be shorter than 100 years, then we definately will have problem finding them.
Then, it is most likely that we are listening through the wrong channels.
Using accelerated electrons for Communication might be a relative ancient phenomena in the universe.
Still we have not seen evidence for quantum entanglement Communication.
However, due to the nature of new findings, let´s not be to sure that it´s impossible yet.
Sooner or later some hard working people find out that quantum networks for Communication already exist interplanetary?

I like the ideat that what we regard as for sure totally impossible, might turn against us one day.

They have left the universe.

Jun 15, 2018 by Gavin

What if the solution is that they all leave this universe. Here are some possibilities.

1. Perhaps this universe is filled with chaos that tends to spawn new life. As such it is dangerous compared to other universes (filled with radiation, supernovae, solar flares etc. There is an alternative universe nearby.

2. They have discovered heaven - it is nicer!

3. We are in a game-world/virtual-world. To make an analogy Morpheus has shown them the red and blue pills. Can you live a lie or do you leave?

4. There is the possibility of war here. All races eventually learn how to make their own private universe. Problem solved - instant rulers of everything. Why would you stay?

5. They discover a way to create a bubble of time. If the universe outside your bubble stays at one moment you have locked your world away from all change in the universe. Your survival is almost guaranteed. Discovery of your world becomes unlikely.

engaged in physics

Jan 29, 2018 by Cashme Morz

Given all of the pros and cons in the main body of the article, the resulting environment where humans are contacted by aliens is so narrow that those aliens that could potentially be in contact with us humans is a very rare occurrence. Some of the factors that would have to be satisfied to allow for meaningful meeting to take place are: 1)sufficient similarities in type of organism. If the differences between us and them are too great, then they would have too little reason to contact us. 2) They and we would have to have the sufficiently similar characteristics to exist within a very narrow time frame. If they were similar to us a million years ago, but are now extremely advanced, to make them too different from us currently, see 1). 3) They may be similar to us in terms of organism type and technology, but have any number of other cons such as them having paranoia or fear of anyone they come across. This tends to indicate a myriad of factors that could go against them contacting us, even if they are here.
We just don't know what all the other factors are that add up to a meeting. A being anywhere near to our complexity could have just that number of factors that add up to allowing or precluding if we meet or not.
So we don't know much of anything as far as meeting up with aliens, whether now, in the near or far future, here on earth or anywhere else, even if we find someone on some other planet. Will we have qualms about going up to them and saying "Hi", or "take me to your leader" or anything that looks like a meeting. To know anything about meeting them we would first have to understand them sufficiently to know if we even want to meet them, observe them, keep out of their way or anything to do with them.

The Solution

Jan 05, 2018 by Will

Our galaxy alone has over 400 billion stars with many of those stars containing planets. If we assume we are the only life that is being naive, look at Earth where there are and have been millions of species throughout this planet's existence all from a mix of habitable conditions for life as we know it on Earth could form. Tool making and technology does not take very much to advance when sentient species evolve and adapt. For example think of how Humans first used tools then used them to make fire then how to use that fire. We had limited intelligence then, but yet we figured out how to use things around us to forge weapons to kill better and eventually make fire ourselves instead of seeing it in nature. All of that is because Humans are a unique, one of a kind creation of Earth, we are sentient. If it can happen on one planet among billions, sentience will arise elsewhere. The answer: Sentient life is a very unique creation within the universe. Yet for that life to achieve the ability to travel among the stars in mere fractions of their lifespans, is an even more rare occasion. While there could millions of species at this very moment at the technological and social state of Humans, there may be as little as 50 to 100 or as many as several hundred. All scattered throughout the galaxy. Yet for any of them to use the same communication techniques and even the same technologies could be a very slim chance. Sentient life adapts depending on where they are and what natural things occur around them. They could develop electricity and use it in all sorts of ways, far before they even discover fire. It all depends on their upbringing.

3.9 5.0 17 17 I think it is disadvantageous for an advanced civilization to advertise its presence. the reason we are is because we are nascent and nieve. I believe the universe is imperialist Possible Answers to the Fermi Paradox

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