Interstellar Civilizations

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Our universe is a beautiful place, it contains everything we know about and everything we aspire to know about. It gave us birth and one day, unfortunately, will bestow upon us death. There are an infinite number of secrets hidden inside the cosmos and this organization is entirely dedicated to uncovering them, we strive to spread the love for science to as many as possible!

Interstellar Civilizations

Have you ever looked up at the sky and wondered — Are we alone?

This question has baffled minds of millions and still does, that’s the beauty about it, a problem is only fun until it has been solved. This post shall peek into the depths of our cosmos trying to find our interstellar brethren.

Goldilocks Zone:

What is a Goldilocks zone? You might have never heard of this term and might find it pretty weird but it is one of the most important if not the most important factor in finding planets that might be hosts to intelligent life. The Goldilocks zone is the specific region in space where it is not to hot nor too cold for a planet to develop simple life and have water on the surface. This zone is also known as the ‘habitable zone’.


According to recent studies, there could be about 40 billion Planets like Earth in just our milky way.

The extent of a star’s Goldilocks zone depends on what type of star it is — Stars are usually classified using the ‘Morgan-Keenan system’ which mainly classifies stars according to their temperatures. The various types of stars are:

  1. O-Type: Temperature- 40000 Kelvin
  2. B-Type: Temperature- 20000 Kelvin
  3. A-Type: Temperature- 8500 Kelvin
  4. F-Type: Temperature- 6500 Kelvin
  5. G-Type: Temperature- 5700 Kelvin
  6. K-Type: Temperature- 4500 Kelvin
  7. M-Type: Temperature- 3200 Kelvin

This sequence of stars is known as the main sequence and the stars inside it are main sequence stars, there are other types of stars too:

  1. White Dwarfs
  2. Super Giants
  3. Red Giants

The Kardashev Scale:

The Kardashev scale has revolutionized the subject of astronomy. This is a scale that provides a specific rating to an interstellar civilization after seeing the amount of energy it uses. A civilization can be rated ‘Type-1’, ‘Type-2’ or ‘Type-3’ using this scale.


Each type of civilization has its various capabilities:-

Type-1 Civilization:

  • This type of civilization would have control over all the energy that would reach their home planet.
  • This civilization would have probably exhausted all of its fossil fuels and would be using natural energy to power the whole planet.
  • They would be capable to travel to all the planets in their solar system and would also be able to control the weather conditions of their home planet.

Type-2 Civilization:

  • This type of civilization would have probably taken control over the majority of the planets in its solar system and could be a multi-planetary species.
  • They would have control over all the energy released from their home star. This would be done using a Dyson’s sphere.

A Dyson’s sphere is an imaginary sphere which would completely surround this civilization’s home star. Its main use would be to trap and transport all the energy released by the star.

This would mean that this civilization would be capable of unimaginable technological feats as it would have access to so much energy. The problem is that to build a Dyson’s sphere you would need very large amounts of energy which wouldn’t be accessible to a type 1 civilization.

So, for a type-1 civilization to turn into a type-2 civilization it would need to find a way to harvest large amounts of energy using the resources they would have.

  • This civilization would be able to travel beyond their solar systems.

Type-3 Civilization:

  • At this stage in the development of a civilization, we could call it invincible or god-like.
  • At this level, this civilization would have control over its mother galaxy and probably all the energy in it, so it would have the power to make itself visible and invisible at their own will.
  • They would be able to conduct thousands of life-like simulations, from which comes the simulation paradox (Will be discussed in another post).
  • They would have the power to construct multiple Dyson’s spheres around different stars simultaneously.

Carl Sagan’s Kardashev Scale:

Carl Sagan is one of the most famous astrophysicists this world has ever seen. He had his own version of the Kardeshev scale, he proposed that civilizations should also be defined using intermediate values not shown in the original Kardashev scale.

The amount of power each civilization would be capable of using would be:

  • Type-1: 10^16 Watts
  • Type-2: 10^26 Watts
  • Type-3: 10^36 Watts

The formula Carl Sagan came up with showed the exact rating of a civilization on the Kardashev scale:



  • K = Final rating on the Kardashev scale
  • P = Power that civilization uses in watts

Using this formula us humans rank at about 0.72 on the Kardashev scale. Scientists suspect that it might take another 70-100 years for us to reach Type-1(At the time of writing).

The Great Filters:

As we discussed before, a civilization can develop to great heights, but to reach that certain level it would have to go through various stages in its development called the Great Filters.

You can call the great filters as hardships a civilization would have to face to attain a type-3 rank on the Kardashev scale. Only the civilizations that pass through these barriers are able to develop into stronger species. There isn’t a specifically defined list of great filters but here are some which are generally accepted:

  1. Formation of Unicellular life
  2. Formation of Multicellular life
  3. Evolution of Multicellular life into intelligent species
  4. Meteoroid hits
  5. Global Warming
  6. Exhaustion of fossil fuels
  7. Nuclear War
  8. etc…

The Fermi Paradox:

The Fermi Paradox is a paradox which highlights the facts that there is a very high possibility for an extraterrestrial civilization to exist but there is no evidence showing its existence.

The solution to this paradox will tell us why we haven’t found any proof of the existence of extraterrestrial organisms.

Let’s lay out the facts first:

  • There are about 400 billion stars in our galaxy.
  • It is said that the average number of planets revolving around a star is 1.6
  • There are about 660 billion planets in our milky way.
  • Let’s assume that 9% of these planets develop unicellular life, that would mean about 60 billion planets would have microbial life on them.
  • Let’s assume 10% of those planets develop Multicellular life, that would mean about 6 billion planets would have simple multicellular organisms on them.
  • Let’s assume 10% of those develop intelligent organisms, that would mean about 600 million planets would have intelligent organisms on them.
  • Let’s assume 1% of those survive and evolve into technologically advanced civilizations, that would mean that our galaxy would contain at least 6 million intelligent civilizations.

So, Where is everybody?


There are hundreds of creative solutions out there but here are 10 unique ones:

  1. We are living in a simulation — Simulation Paradox.
  2. We cant receive or read their messages so we don’t know where they are.
  3. Aliens are watching us make our own identity in this universe without any interference.
  4. God Exists and he favours our survival.
  5. They are already on Earth and are spying on us.
  6. They don’t want to contact us as we might be extremely underdeveloped for them.
  7. Somehow, we are the only ones who evolved into intelligent organisms.
  8. All kinds of civilizations believe that sending communicative signals would jeopardize their safety.
  9. Others haven’t yet discovered modern science.
  10. Other civilizations keep destroying themselves through war.

The Drake Equation:

The Drake Equation is used to find the number of communicating civilizations in our universe. It doesn’t have one definitive answer but the accuracy of the answer depends on the values you plug into the equation.

The equation is as follows:


We haven’t yet found out the exact values for each variable but we can always enter our estimates.

Lets try and put some values in:

  • R = 2; Rate of formation of stars in galaxy (Stars/year)
  • f [base p] = 0.5 ; Fraction of stars that form planetary systems
  • n [base e] = 0.5 ; No. of habitable planets per star (Average)
  • f [base l] = 0.2 ; Fraction of habitable planets on which life appears
  • f [base i] = 0.05 ; Fraction of planets on which life appears and evolves into an intelligent species.
  • f [base c] = 0.5 ; Fraction of intelligent species that develop technology for interstellar communication.
  • L = 1000 ; Years a civilization remains detectable

Plugging these values into the equation we get:

N = 2.5; Number of technologically advanced civilizations in the milky way galaxy.

KIC 8462852:-

‘KIC 8462852’ is a very unusual star, it is said to be an F-Type star and is about 1,470 light-years away or about 450 parsecs away. The reason I mentioned this star is because it has been showing very unusual fluctuations in its light emission. It can’t be planets or other celestial objects in front of it as the light sometimes dims up to 22%.

This unusual activity might suggest that there is a Dyson’s sphere being constructed around the star or it has already been constructed. This might be the discovery of an interstellar species or just some kind of space debris, what do you think? Leave your answers in the comments I would love to read them.


I hope this post made you look towards the sky and ask one question again and again — Where is everybody?

Thank you for reading, hope you learned something new!


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One thought on “Interstellar Civilizations

  1. I wish there was some scientist who would come up with a way to harness the energy and reduce the expected time of 70-100 years for us to reach Type I.

    Btw, the activities on KIC 8462852 are top secret…

    Jokes apart, I think assigning a value of 0 to any one term of the Drake equation will explain why we haven’t found any other planet with inhabitants.

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