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Our ancestors saw the firmament as a simple map of stars that served to guide them. Thanks to the theory of relativity and measurements made with telescopes, we now know that the cosmos is bigger, older and more full of objects than the human being could have imagined.

As its complexity was discovered, we stopped believing that we were the center of the universe. Knowledge has displaced us to a place like a small planet orbiting an insignificant star.

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Taking into account that space has more than 10 billion galaxies and each of them contains more than 100 billion stars, we do not seem to be very important.

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Now we know that the universe expands, space stretches and with galaxies happens as when we paint points on a globe. As we inflate these points are moving away, so it is with the galaxies.

Experiment:
Several spots are painted on a balloon and inflated. We can see how the points are separated as the balloon is larger. This is how the universe works.

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Therefore the more the galaxies separate, the more our Milky Way will remain alone. Although with the telescopes it allows us to see objects that are increasingly distant from us, in reality everything we observe is the past of the universe.

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For example, the light that comes from a galaxy that is at a distance of 100 million light years will show us exactly what it was like 100 million years ago, which is the time it took the light rays to reach us . As our telescopes see further what we observe is the remotest past of the universe, galaxies and ever-younger stars.

^{Yes, it may sound confusing. But this I can explain in another publication...}

The acceleration with which the universe expands is uniform and that allows us to calculate the inverse process, that is, the moment in which everything started.

Cosmic Microwave Background

It happened 13.8 billion years ago, and that is what we know as the Big Bang. Before the Big Bang there was no time or space, and all the matter and energy of the universe were concentrated at an almost infinite density and temperature. From there the cosmo has only cooled and grown, creating the particles that gave rise to the atoms and then formed the stars, planets and galaxies.

Big Bang Theory gif

In the universe there is much more matter and energy than what we are able to see, that's why we talk about dark matter and dark energy. It is estimated that 70% of the energy and about 80% of the matter are dark.

Meanwhile the matter that if we can perceive is diluted, there will come a time when everything that we can observe will disappear, leaving a cold and empty universe. But you do not have to think about that now.

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The universe is so big that we could say that it is infinite, if you wanted to give the direction of your planet earth, would you know where it is located?

Imagine that a Martian friend wants to visit you and asks for your address, what would you answer?

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Well, from the studies you have had, you would know that we are in the Milky Way. But I'll give you some help.

Earth is the third planet that orbits the star Sun.

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The Sun is one of the billions of stars that make up our galaxy, the Milky Way. This is a spiral type galaxy, where we can differentiate two zones.

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The Bulb	The Disc
It is where the oldest stars are staying, accompanied by a large black hole.	It is the modern part, it is well loaded with light elements, the perfect place for new stars. This is our neighborhood.

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Specifically, the Sun is in one of the spiral arms. The so-called Local Arm or Orion Arm.

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The Milky Way is one of the three largest galaxies in the Local Group. A set in which they are:

Andromeda, the galaxy of the triangle, and a large number of small galaxies, called satellite galaxies that orbit the aforementioned.

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We could say that they are like small villages and we live in a Citadel, that in a few thousand years we will be in a much larger one. The Milky Way and Andromeda will be merged.

We return to the Local Group, which finds many more galaxies within the Virgo Supercluster and which is the Supercluster of Laniakea.

Virgo Supercluster

Laniakea Supercluster

We practically got here, because it is almost impossible to determine where the Supercumulus of Laniakea is located, in summary our address is:

1- The Earth
2- Solar System
3- Arm of Orion
4- Milky Way
5- Local Group
6- Virgo Supercluster
7- Laniakea Supercluster

So let's hope that our friend Marciano lives inside this one.

So I say goodbye until a next post. I hope you enjoyed this summary of what our universe is and where we are located, in a world full of mysteries and fascination.

Greetings!

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^{Sources: 1 - 2 - 3 - 4 - 5 - 6 - 6 - [7. Student Encyclopedia]}