What are constellations and why scientists are still taking advantage of this millenary tradition

The human being has from prehistory looking at the night sky to guide himself, either looking for the north to establish our course, or in order to know what is the ideal time for the planting of a crop. We have also often sought in the stars the esoteric and the divine.

The stars have helped us to locate in space and time. And to guide ourselves in the tangle of bright dots that populate the night sky we have often resorted to an old “trick”: the constellations.

What is a constellation

The constellations are Star groups that are close to each other in the celestial vault. Not so in the universe, the stars that share a constellation Thousands of light years can be located on each other, it is only their position related to the field of vision that we have on earth.

The constellations were created when our ancestors assigned a form to these groups: whether the shape of a person or deity (as in the constellations of Andromeda, Orion or Virgo), an animal (the major and minor bears, or the constellations of Aries and of Taurus), an object (such as Erídano, the oven or the clock) or other mythological being (such as the hydra or draco).

The constellations change depending on the time of the year and the region in which we place ourselves: there are constellations that are only visible in winter, others in summer; Some can only be seen from the southern hemisphere and others from the north. All this due to the relative position of the earth regarding the “backdrop” of the universe and the sun, which blinds our vision of the stars during the day.

The constellations are therefore groups of stars in our sky and the way in which their position is distributed. Groups that were probably used Since ancient time as a mnemonic trick to distinguish stars and, with them, identify times of the year or to use as a compass with which to guide us.

How many constellations are there?

To use constellations as a systematic tool, scientists have developed an “official” constellation list. Thanks to this we can list a specific amount of constellations. How many? 88 in total.

And who says it? The institution in charge of designating constellations is the International Astronomical Union (UAI), responsible for the nomenclature of many other elements in space and in the celestial vault.

The delimitation of the celestial borders depending on the constellations as we know it today was approved by the UAI almost a century ago, in 1930. It was then that the proposal of the Belgian astronomer was published Eugène Joseph Delporteapproved two years before by the General Assembly of the agency.

What is the origin of the constellations

These constellations came to us through ancient Greece, but we know that they did not originate there but had a even older originperhaps in the Babylonians or in other civilizations of the surroundings of the “fertile growing”. We also know that this type of cartographies arose In various civilizations Far from each other, from South America to China.

These constellations came to us through ancient Greece, but we know that they did not originate there but that they had an even older origin, perhaps in the Babylonians or in other civilizations of the surroundings of the “growing fertile” lifting. We also know that this type of cartographies arose in various civilizations distant from each other, From South America to China.

The origin of the “modern constellations” is in two points. The first, the fact that the era of exploration led Europeans to have to orient themselves in the southern hemisphere, where some of the constellations are not visible, but where the reference of these can also be useful.

How science uses constellations

Although constellations are based on tradition and not on the use of the scientific method to order the stars, science makes use of them in certain contexts. Precisely this need to “cover holes” It is due to the use made by constellations today and is to serve as a reference for the Observation of objects and phenomena astronomical.

The celestial vault can be divided into latitudes and lengths, with its degrees, minutes and seconds, in the same way we do with the surface of the globe. This way of dividing the sky can be useful, but it is also not very intuitive if we do not have other references. On Earth we have cities, countries and continents; In the sky, constellations can help us intuitively locate a specific point in the vastness of the night sky.

Difference between constellations and galaxies

Are not the galaxies of stars also? The constellations resemble galaxies in the fact that both terms refer to groups of stars, but beyond this fact, the differences are non -existent.

While constellations represent groups of stars that are in proximity from our perspective, galaxies are formed by groups of stars that are found gravitationally anchored each other. Galaxies are also composed of many other elements linked in the same way, from dust and gas clouds even black holesthrough planets and asteroids.

The terminolgia can be confusing by the way we have to name some and other elements. For example, if we talk about Andromeda we can be referring to both a constellation and The homonymous galaxy. This coincidence is precisely because the galaxy was baptized with the name of the celestial region where you have to look to find it: the Andromeda constellation.

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Image | Stellarium Web / NASA