According to DigoPaul, Andromeda was the wife of Perseus, with whom he had seven children. Daughter of Cassiopeia and Cepheus, she was delivered by her father to Ceto, although she was rescued by the mentioned Perseus.
The mythology that Cassiopeia angered Poseidon when presumed to be more beautiful than the Nereids. The god of the waters then decided to send the monster Keto to end humanity. In this framework, Cepheus discovered through an oracle that the only way out was to deliver his daughter Andromeda to Ceto, for which he chained her to a rock. When Perseus saw Andromeda, he fell in love with her and asked his parents for the hand. Thus he released Andromeda and then defeated Ceto.
Once Andromeda passed away, mythology notes that Athena placed her in a stellar constellation. From this idea, the Andromeda concept arises as it is understood in astronomy.
Andromeda, in this context, is the name of a constellation that contains a galaxy of the same name, although in a technical field the latter is known as Messier 31, NGC 224 or Spiral Galaxy M31. It is a colossal spiral whose diameter exceeds two hundred and twenty thousand light years and in its range are close to a trillion stars.
The Andromeda galaxy is, for most observers, the farthest object that we can easily see from our planet; however, there are those who say that this title belongs to the galaxy of the Triangle, which is even further away (specifically, 2.5 million light years in the same direction as the previous one).
It is known under the name Local Group to the cluster of galaxies in which the Milky Way is along with other Thirtytwo, including Andromeda, the largest and brightness of all. As a curious and, for some, worrying fact, scientists have observed that Andromeda is constantly approaching our galaxy at a speed of 300 kilometers per second, which means that in about five billion years at most there will be a collision between the two which will lead to a merger from which a supergiant elliptical galaxy will emerge.
The total mass of Andromeda has not yet been accurately calculated, and for this reason the values found in specialized sources have a wide range. While certain scientists claim that our galaxy contains a much higher amount of dark matter, some recent studies have revealed the exact opposite. Dark matter is that which does not emit or relate to any kind of electromagnetic radiation, but is absolutely transparent throughout the electromagnetic spectrum; it is estimated that it represents 27% of the universe.
Another of the characteristics that some specialists attribute to the Andromeda galaxy is its high level of brightness, so much so that only one of those known to man can overcome it in this regard. On the other hand, given the orientation it is in with respect to our observation points, it is not easy to carry out the calculation of its luminosity, and this gives rise to different results, depending on the method used. Still, scientists generally agree that it at least beats our galaxy in luminosity.
It is worth mentioning that Andromeda is also the name of a genus of shrubs to which medicinal properties are attributed; the name of a mountain that is located in Canada and whose height reaches 3,450 meters; and the title of a TV series that aired in the United States between 2000 and 2005.