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Friday, 27 February 2015

Is There Anybody Out There ?

My Kenyan friends always complain about the weather. When it is below 20 Celsius (68 F) it is too cold. When it is above 25 Celsius (77 F) it is too warm. They can hardly imagine the European temps that range from about - 40 Celsius (- 40 F) to + 40 Celsius (104 F). By the way, the highest temperature ever recorded on Earth was +58 Celsius or 136 Fahrenheit in the Libyan desert. The coldest temperature ever measured was -88 Celsius or -126 Fahrenheit at Vostok Station in Antarctica. Source:

These temperature complaints made me realise something: the more intelligent life is, the more stable environmental conditions it needs to sustain itself. In extreme conditions (e.g., ocean bottom, polar cold, sky high, volcanic heat) we still find life but only basic, simple, organisms. I suppose these organisms need all their energy to maintain themselves against their extreme environment which leaves no room for developing intelligence. This leads me to conclude that any intelligent life form could only develop within a rather stable and "friendly" environment.

The preconditions for developing intelligent life in a stable (non extreme) environment must be a sun, gravity, water and an atmosphere. That should narrow down the probabilities of intelligent life forms.

Our universe consists of galaxies and systems and planets. Planet earth is in the Earth or Teran or Solar system, which is a system in the Milky Way Galaxy, which is part of the entire Universe. Apparently there are perhaps 100 billion (10^11) stars in a galaxy and 100 billion (10^11) galaxies in the universe, giving something in the order of 10^22 (a.k.a. 100 sextillion) stars.

The Sun is about 4.5 billion years old. Since its birth it has used up about half of the hydrogen in its core. It will continue to radiate "peacefully" for another 5 billion years or so although its luminosity will approximately double in that time. But eventually it will run out of hydrogen fuel. It will then be forced into radical changes which, though commonplace by stellar standards, will result in the total destruction of the Earth. Source:

Our Sun is a star but a very special star that gives fire, light, and is self luminous. How many of such very special stars would there be in the universe? It took me some time to find an answer to this simple question. 

A "habstar" - or solar twin - is a star with qualities believed to be particularly hospitable to an Earth-like planet. Qualities considered include variability, mass, age, metallicity, and close companions. Search conditions: At least 3 billion years old, on the main sequence, non-variable, capable of harbouring terrestrial planets and supports a dynamically stable habitable zone. Search results: one example of such a star is HD 70642. Source:

That search result was just about one of my earlier preconditions (sun, gravity, water and an atmosphere). The other preconditions (gravity, water and an atmosphere) cannot be tested as HD 70642 is a yellow dwarf star in the constellation of Puppis located 92 light years away. Source:

Despite the zillions of planets and stars around us, we may be more unique than we assume to be.

Pink Floyd - Is There Anybody Out There: