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The quasars are distant objects that emit large amounts of energy, similar to the star radiation. The quasars are hundreds of billions of times brighter than the stars. Possibly, they are black holes that emit strong radiation when they capture stars or interstellar gas.
The light that we perceive occupies a very narrow range in the electromagnetic spectrum and not all the cosmic bodies emit most of their radiation in the form of visible light. With the study of radio waves, radioastronomers began locating powerful radio sources that do not always correspond to the visible object.
The word quasar is an acronym for quasi stellar radio source (almost stellar radio sources).
Identification of quasarsThey were identified in the 1950's. Later saw that they showed a shift to larger than any other known object red. The cause was the Doppler effect, which moves towards the Red spectrum when objects move away.
The first studied quasar, 3 c 273 is 1.5 billion years Earth light. Since 1980, thousands of quasars have been identified. Some move away from us at speeds of 90% of the light.
Quasars have been discovered to 12 billion years Earth light. This is roughly the age of the universe. Despite the enormous distances, the energy that comes in some cases is very large. As an example, the s50014 + 81 is about 60,000 times brighter than all the milky way.
The most spectacular of the quasars is not its remoteness, but that they may be visible. Quasar must be as bright as 1,000 galaxies together so it can appear as a faint star, if light is thousands of millions of years. But even more surprising is the fact that this huge energy comes from a region whose size does not exceed a year light (less than one thousandth of the size of a normal Galaxy). The brightness of the quasars varies with periods of a few months, therefore, its size must be less than the distance that light travels in that time.
At first, astronomers did not see any relationship between the quasars and galaxies, but the gap between these two types of cosmic objects has been filling slowly to discover galaxies whose nuclei present similarities with the quasars. Today, it is thought that the quasars are very young galaxies nuclei, and activity in the nucleus of a Galaxy decreases over time, although it does not disappear at all.
Translation for educational purposes authorized by: Astronomía: Tierra, Sistema Solar y Universo