Concept in Definition ABC

In the fourteenth century there was the so-called Revolution Copernican promoted by Copernicus and later by Galileo. With this revolution of the astronomy the human being began to be aware that the Sun was the center of the universe and that the Earth orbited around it.

Together with other celestial bodies the planetary system known as the Solar system. From this finding, astronomers thought that, logically, there had to be other planets orbiting other stars. These planets were called exoplanets.

However, it wasn't until 1992 that astronomers discovered the first exoplanet.

Certain exoplanets could have sufficient conditions compatible with life

At present it has been confirmed that there are more than 500 exoplanets or extrasolar planets. On the other hand, it is believed that some of them could be located in the habitable zone, that is, that area in which it would be possible for there to be liquid water on its surface.

According to astronomers and astrobiologists, if a planet contains liquid water, it is very likely that there is some form of life on it. The exoplanet Gliese 581, which is more than 20 light years from Earth, is the exoplanet with the best conditions to host any form of life.

The exoplanet Proxima B, which orbits the red dwarf star near Centauri, could be habitable because it is a rocky planet, with a mass slightly greater than that of Earth and is within the zone habitable. The distance between Proxima B and the Earth it is about 4 light years, which means that to reach it with a shuttle it would take about 165,000 years. In order to get to Proxima B with more speed astronomers are working on a draft of nanoprobes that travel much faster than conventional spacecraft and it is estimated that this could be achieved in the next 50 years.

According to astronomers, the number of planets outside the solar system could exceed 40,000 million

In this sense, a few decades ago it was thought that stars with planets were a rarity in the universe, but today it is believed that it is something relatively normal.

Exoplanets are not easy to detect, since their light is diluted by the star they orbit around and they are found at great distances. Various methods are used for the detection of exoplanets:

1) the observation direct visual from a telescope on Earth or in some orbit,

2) indirect methods, such as the velocity radial that allows to deduce the mass and orbit of a planet and

3) the method of transit, by which the intensity of the light of these planets is detected through sensitive instruments of great precision.

Photos: Fotolia - Peter Jurik - GiroScience