12 reasons why we haven't met aliens yet

In the Milky Way galaxy alone, there are about 400 billion starsHow Many Stars in the Milky Way? /NASA Blueshift and at least as many planets. Of these, at least 17 billion are similar to our Earth. And about 300 million inhabitedS. Bryson. The Occurrence of Rocky Habitable Zone Planets Around Solar‑Like Stars from Kepler Data / The Astronomical Journal or at least habitable.

But if there are so many potentially habitable worlds and highly developed civilizations can easily be located on them, why is there still no news from them? This is the so-called Fermi Paradox. And various scientists have proposed many solutions to it. Here they are.

1. We are alone in the universe

The simplest explanation for the Fermi paradox is that humanity is the only intelligent species in the universe. Well, or the Earth is the only planet on which life originated. This option suggestedP. D. Ward, Du Brownlee. Rare Earth: Why Complex Life is Uncommon in the Universe

paleontologist Peter Ward and astronomer Donald Brownlee.

Indeed, a solid planet with a large moon, not far and not close to its sun (in the so-called habitable zone), which has not been exposed to the sterilizing radiation of surrounding stars and quasars for billions of years - this is not often seen.

However, the unique Earth hypothesis criticizeJ. Cohen, I. Stewart. Evolving the Alien for numerous inputs. Statistics are against it: in our Galaxy alone, even hundredths of a percent of the stars look quite suitable for supporting life on their planets. And these are tens of millions of worlds.

2. Civilizations self-destruct in time

In 1996 Professor Robin Hanson of George Mason University developed Another explanation for the Fermi Paradox is the Great Filter Hypothesis. He suggested that any civilization at a certain stage of its development faces some kind of obstacle on the way of space colonization, and no one has yet overcome this problem.

Let's say, life was born on some planet, developed into a reasonable one, built cities, went into space… Then it would be nice to fly to the Galaxy to conquer, but something happens - and all grandiose plans are covered with a copper basin.

After all, when you have a big red button with the inscription “Do not press” in front of you, it is so difficult to resist the temptation.

For example, alien kids unleashed a nuclear war, or experimented with their highly developed nanobot viruses, or tritely made a black hole in some kind of collider (just kidding). And civilization either disappears, or rolls back in development and remains to vegetate on its globe. Here is the Great Filter for you.

3. Life moves too slowly

Another option that explains the paradox is that the average civilization in the universe exists too short to start colonizing other planets. But this is not connected with the craving for self-destruction, but with natural reasonsN. Bostrom, M. M. Ćirkovic. The Fermi Paradox and Mass Extinctions / Global Catastrophic Risks.

Well, as soon as you invented the first rocket on your planet and the local Gagarin flew into space - and then bang, your sun turns into a red giant. Or the world is covered by a pandemic of a virus unknown to science. Or a gamma-ray burst from a neighboring quasar arrives. And that's it, life is either destroyed or thrown back down to the simplest.

And even if you are the simplest, it’s not so easy to survive, in fact, if the conditions on your planet are far from hothouse. So, perhaps the aliens do not contact us simply because they already died outThe Aliens Are Silent Because They Are Extinct / Astrobiology.

4. Space distances hinder interplanetary friendship

As you can see, space is big. Even if you accelerate the ship to the speed of light - what impossibleHow Fast Does Light Travel? /Space.com, because its mass will then become infinite - it takes more than four years to fly to the star closest to us, Proxima Centauri.

By estimatedS. von Hoerner. The Search for Signals from Other Civilizations / Science astrophysicist Sebastian von Horner, the average age of a normal self-respecting civilization is somewhere around 6,500 years, and the average distance between civilizations in the Milky Way is 1,000 light years.

That is, even if we manage to receive some messages from brothers in mind, you will need to sit with the receiver for about a thousand years in order to be able to establish any meaningful dialogue.

And to fly to an alien civilization on a visit with current technologies is an almost impossible task. And given that the universe is expanding and the distances between galaxies are only increasing, the prospect becomes even sadder.

So sorry, we'll have to wait until one of us invents some kind of warp drive.

5. Aliens are hiding

Well, not on purpose, of course, but they just have such a way of life. Planetary scientist Alan Stern suggestedA. S. Stern. An Answer to Fermi's Paradox In the Prevalence of Ocean Worlds? /NASA/ADSthat many alien civilizations may exist not on the surface of the planets, but under it. For example, in oceans frozen from above, as on Europa, the moon of Jupiter, or Enceladus at Saturn.

Life on such a planet is reliably protected from supernovae, adverse conditions on the surface and other disasters. Build your own underwater megacities, and what's going on up there is absolutely on the drum.

Again, such civilizations may not know that they have something above their heads, and are able to believe that their planet is the Universe.

No radio waves or signals will notWhere Are All the Intelligent Aliens? Maybe They're Trapped in Buried Oceans / Space.com break through the ice from above, and the lights of underwater cities are not visible from space. And therefore, such a civilization is extremely difficult to detect. In addition, if a technologically advanced race uses not radio, but fiber optic communications or something else, it will not leave a trace on the air.

Finally, a particularly highly developed civilization can corny surround its star with a huge impenetrable Dyson sphere, isolating itself from the world.

6. Aliens exist in virtual space

Why conquer space when you can instead put on virtual reality glasses and sit on the beach surrounded by hot babes in a computer simulation? And if you completely transfer your consciousness to a digital medium, then you will also become immortal! It's not up to sending signals into the void and inventing warp drives.

At least such an explanation of the Fermi paradox put forwardS. webb. If the Universe Is Teeming with Aliens… Where is everybody? scientists from the University of Massachusetts. The aliens could well decide that the real universe is too boring, and go into the virtual, abandoning even the physical bodies.

That's why they don't contact us - it's more interesting to shoot headcrabs and buy yourself new avatars in his version of the metaverse from the alien Zuckerberg than hanging out in real life with slow leather bags.

7. Alien life forms are too alternative

There is such a thing as carbon chauvinism. Scientists, talking about alien life, imagine it to be the same as terrestrial life - formed from water and carbon and breathing oxygen.

However, theoretically there could be other forms - for example, creatures of silicon, literally made of clay like montmorillonite. Or nitrogen-breathing phosphorus creatures, or in general individuals made of hydrogen living in the atmosphere of giant planets.

With more highly organized alien creatures, it is still more difficult: we simply do not understand where to look for them.

They can, for example, live in wormholes, like suggestedThe Great Silence of the Universe / Lecture Hall of the Polytechnic Museum Russian physicist Nikolai Kardashev. Or exist in your pocket dimensions, microuniverses, multidimensional spaces, and so on.

Or aliens can live in our universe, but in some very interesting place. Astronomer Frank Drake suggestedLife on a Neutron Star: An Interview With Frank Drakethat microorganisms, and intelligent ones, can also exist on neutron stars.

It is extremely difficult not only to contact such comrades, but even simply to understand what they are and how they can be detected.

8. Aliens are afraid and sit quietly

There is the so-called dark forest theory, which got its name from the novel of the same name by the Chinese science fiction writer Liu Cixin. According to her, aliens do not joinG. Brin. The Great Silence - the Controversy Concerning Extraterrestrial Intelligent Life / Quarterly Journal of the Royal Astronomical Society in contact with people and other distant civilizations, not because some technical obstacles do not allow them, but because they are afraid.

On Earth, for example, contacts between highly developed societies and less developed ones ended in bloodshed, epidemics and other troubles. Think about exterminationM. Hill. Gold: The California Story Indians conquistadors or about conquestWalking "Meet the Sun" in the Context of the Problems of Accession of the Far East to the Russian State / Cyberleninka indigenous peoples of Siberia by Russian Cossacks.

If visitors arrive on one planet from another, they may well want to kill the local population.

Firstly, this way you can eliminate competitors before they develop into something potentially dangerous. Secondly, extra living space does not hurt - inhabited planets do not lie on the road. Third, why not? We have plasma disintegrators and railguns, what will you do to us?

It is not surprising if it turns out that alien creatures they just don't want to risk messing with other sentient species and jam their radio transmissions so no one can track their planet.

And even if the aliens are not hostile, they may well bring some kind of intergalactic smallpox virus, to which they themselves are immune.

9. Our technologies are too different

Humanity looking forM. C. Turnbull. Target Selection for SETI: 1. A Catalog of Nearby Habitable Stellar Systems / Astrophysics alien civilizations with the help of artificial radio signals at certain frequencies of the range - this is the case, in particular, for the famous SETI project. If aliens use radio communications and emit something into the air, then they can be tracked and listened to, and then even establish a data exchange.

The problem is that extraterrestrial civilizations may well use alternative technologies and leave no trace on the air.

Let's say they use signal compression methods different from ours, which makes their data perceivedM. Kaku. Physics of the Impossible like white noise. Or they generally use technologies that are inaccessible to us - for example, they can communicate using neutrinoJ. G. Learned. Galactic neutrino communication / Physics Letters B.

10. Aliens consider the Earth a nature reserve

zoo hypothesis suggestsJ. A. Ball. The Zoo Hypothesis / NASA/ADSthat aliens are more advanced than people, and do not contact us, not because they cannot, but because they do not want to. They say, let them swarm around on their green-blue globe, and we will observe and not interfere. Perhaps the Earth is viewed by them as something like a zoo, a nursery or a nature reserve.

A more free version is the planetarium hypothesis of mathematician Stephen Baxter. Perhaps a highly developed civilization is not only intentionally avoidsS. Baxter. The Planetarium Hypothesis - A Resolution of the Fermi Paradox / Journal of the British Interplanetary Society connection with earthlings, but also deliberately surrounded the planet with uninhabited spaces or some kind of illusion to make stupid people think that they are alone in the universe.

11. Aliens are not interested

A fairly simple answer to the Fermi paradox: alien civilizations do not communicate with people simply because they boringS. webb. If the Universe Is Teeming with Aliens… Where is everybody?. Well, what interesting things can leather bags tell them?

You do not seek to make contact with the underdeveloped tribes of the Amazon Basin, the pinnacle of scientific thought of which is a digging stick. It is quite possible that alien civilizations also treat people.

We are here in the Andromeda galaxy in our minds so overwhelmed... And in general, the construction of the Dyson sphere is behind schedule, we are not up to you.

Maybe there are a dime a dozen of underdeveloped civilizations on planets like Earth in the Universe, and it’s simply not easy to study each of some Intergalactic Empire - there is no scientific value in this. It is much more interesting to light quasars and push black holesthan to show some natives who you are and where you came from with gestures and bellows.

Let them master interstellar jumps, then we'll talk.

12. Intelligent species have not yet developed enough

Alternative to the previous point of view: alien civilizations existS. webb. If the Universe Is Teeming with Aliens… Where is everybody?, but are at a very low level of development. And only people have mastered radio broadcasts so far, and the rest of the humanoids live in Middle Ages or even the Stone Age and use signal fires or invocative whistles.

For example, astronomer David Byrne thinksT. b. H. Kuiper, G. D. Brin. Extraterrestrial Civilizationthat our Earth is a rather rare phenomenon due to the fact that it is relatively close to the Sun. Other earth-like planets, he believes, are more distant from their luminaries, and therefore they have much more water and less land than ours.

Under such conditions, some intelligent dolphins, whales or squids can easily develop, but they cannot create a technological civilization, and they will be forever locked on their planet.

And really, go build an orbital telescope when there is an ocean around you - there is nowhere even to make a fire.