Category Archives: I only know that I don’t know anything

Cosmic Calendar

I have already mentioned in previous posts that I am a HUGE Carl Sagan fan, not just because of his expertise in several science areas, but also because he loved to share everything he knew with calendariopeople and he did it in a way that was really easy to understand for everyone.

One of my favorite explanations made by him is the cosmic calendar and it is precisely the topic of this post.

The main purpose of the cosmic calendar is to represent the history of the universe in a calendar year (from January to December) since the Big Bang till today. The object is to represent the most important events in a timeline to have a better perspective and understanding of what happened billions of years ago.

Having this in mind, this is how the cosmic calendar looks like:


  • January 1st: The Big Bang. The universe is formed.





  • May 1st: Origin of the Milky Way.


  • Planetary systems are formed.


  • Planetary systems are formed.


  • Planetary systems are formed.


  • September 9th: Origin of the Solar System.
  • September 14th: Formation of the Earth.
  • September 25th: Origin of life on Earth.


  • October 2nd: Formation of the oldest known rocks.
  • October 9th: Oldest fossils.


  • November 1st: Sexual differentiation.
  • November 12th: Oldest photosynthetical plants known.
  • November 15th: Eukaryotes appear (first cells with a nucleus).


  • December 1st: Formation of an atmosphere filled with oxygen on Earth.
  • December 18th: First plancton.
  • December 19th: First fish. Vertebrates appear.
  • December 21st: First insects.
  • December 23rd: Reptiles appear.
  • December 24th: First dinosaurs.
  • December 26th: Mammals appear.
  • December 28th: First flowers. Dinosaurs become extinct.
  • December 29th: First primates.
  • December 31st: First human appears.


Temporary Scale:

Ω A month represents 1.25 billion years.
Ω A day represents 40 million years.
Ω A second represents 500 years.


When I first read this data I found myself in a universal context in which I had never been.

On the next post I’ll give the detail of what happened on December 31st of the cosmic calendar.

If you want further information about the topic you can find it in the famous Carl Sagan’s TV series “Cosmos” or in his book  “The Dragons of Eden.” In youtube you can also find related content.

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One click

Whenever you feel you have the whole world in your hands or if on the other hand your problems overwhelm you too much, just push the red button:

red button

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Pretty, pretty

NGC 7331

This is the NGC 7331 galaxy, and is about 50 million light years away. It is found in the Pegaso constellation and was discovered by William Herschel in 1784.

It has been considered similar to ours, the Milky Way, because of  its mass, number of stars and rhythm on stellar formation. But it has been proved that this galaxy is much more brilliant and massive than ours.

It is really possible there is life in this galaxy and in many others… or do you think we’re alone in the universe?

Image from Vicent Peris (OAUV/Pteam), Gilles Bergond, Calar Alto Observatory.

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A little bit of numbers

Triángulo de Pascal

Pascal's Triangle

The concept is simple: each number inside each box represents the sum of the number written above it and the number written on its left.

This triangle created in 1665 by Blaise Pascal has become one of the most representative images of the history of science, mainly because it contains numerous mathematical patterns.

For example, the first column in the left side shows number “1” numbers, the next column shows countable numbers “1,2,3,4…”, the third column shows triangular numbers “1,3,6,10…”, the fourth column shows tetrahedral numbers “1,4,10,20…”, and so on.

It also contains probability patterns, polynomial numbers, horizontal sum sequences and the Fibonacci sequence, among other things that can be seen here.

Is math in everything?

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