Large Magellanic cloud, definition and study. A-Z index of Cognitio.

The Large Magellan Cloud is a dwarf galaxy, probably a satellite of the Milky Way, and the largest of the two Magellanic Clouds.

Milky Way, definition and study. A-Z index of Cognitio.

Milky Way

Given its relatively short distance of only 157,000 light-years, it is the Galaxy closest to the Milky Way after the Great Eagle’s Ellen dwarf and Sagittarius dwarf, the latter placed on the opposite side of the galactic center with respect to the solar system.

Galaxy, definition and study. A-Z index of Cognitio.


The Large Magellanic Cloud has a mass equivalent to about 10 billion times that of the Sun, about one-tenth of the mass of the Milky Way, or about 10 billion stars; with a diameter of around 7,000 light years, is also the fourth largest Galaxy in the Local Group, after Andromeda, the Milky Way and the Triangle.

Sun, definition and study. A-Z index of Cognitio.


It is visible to the naked eye as a weak object in the night sky of the southern hemisphere of the Earth, at the boundary between the constellations of Dorado and Mensa. It is so-called in honor of Ferdinando Magellano who observed her along with her companion (the Magellanic Small Cloud) on her earthly voyage. In the Cloud is the Tarantula Nebula, the most active star formation region of the Local Group of Galaxies.

In addition, in 1987, the explosion of what would become famous as Supernova 1987a was observed in the Cloud. Although the Large Cloud is often seen as an irregular galaxy, it contains a very thick bar across its center, suggesting that it was originally a jumbled spiral galaxy which, due to the great tidal forces due to interaction with our Galaxy and the Magellanic Little Cloud, has suffered deformations. Much of the Cloud falls within the boundaries of the Dorado constellation. It is shown in a unbeared sky like a vaguely ellipsoidal shade of light, giving the idea of a separate Milky Way shale, visible twenty degrees east. It is identified without great difficulty, about 20 degrees south-southwest of the brilliant Canopus star; the most notable part of the Cloud is located in the northeast corner, and is made up of the Nebula Tarantula, whose blurry blur is also visible to the naked eye in the darkest and clearest nights. The most noticeable feature of the naked eye is the large central bar that crosses it in the east-west direction, where most of the celestial objects are concentrated, many of which are also visible with an amateur telescope; the north side of the bar looks very fragmented and irregular, rich in widespread nebulae and fields of young stars. The south side, however, which falls into the constellation of the Mensa, does not host remarkable objects and its dimensions are lower than the north. Like most irregular galaxies, the Large Magellanic Cloud is packed with gases and powders in which frequent intense and vigorous stellar phenomena occur. The most obvious example is given by Nebula Tarantula, the largest star formation region of the entire Local Group. The Large Cloud is rich in celestial objects and phenomena of all kinds that gives scientists the ability to analyze and study cosmic reactions, including stellar evolution;

Cosmic space, definition and study. A-Z index of Cognitio.

Cosmic space

An example is given by the supernova SN 1987a, which exploded near the Tarantula Nebula in February 1987: the object that gave rise to the explosion was not, as one would expect, a red giant, but, on the contrary, a super-gigantic blue super-massive . This supernova was also the closest observed in recent centuries, as well as the first one after the invention of the telescope. The brightest star of the Large Cloud lies along its central bar, and is the variable S Doradus: invisible to the naked eye. Considering its enormous distance, its maximum magnitude is at most about -10, which means that if it was set at a distance of 32.6 light years from Earth, it would be able to project shadows of objects. Within the galaxy, two other super-gigantic stars have been recently observed, cataloged as R 66 and R 126; belong to class O, that is, they are extremely massive and bright stars, of blue color and with very high surface temperature. Strangely, around them there is a dust disc. An international team of 24 researchers led by Mikako Matsuura selected a group of stars to study with NASA Spitzer Space Telescope by analyzing their spectrum to find organic material outside the Milky Way.

Space telescope, definition and study. A-Z index of Cognitio.

Space telescope

This is what hides the satellite galaxy. There are so many secrets and things to find out if the telescopes are pointing beyond the boundaries of our Galaxy and it is not said that the bricks of organic life are not here and there in interstellar space. Poly cyclic aromatic hydrocarbons (PAHs) are substances naturally found in fossil and petroleum. On Earth, however, they are carcinogenic and highly polluting while in space they play a protagonist, being the basis of the star formation cycle. Scientists, over the years, have studied these substances precisely because they are considered key to understanding the evolution of carbon-rich environments such as those around the dying stars. Recent observations focusing on the search for PAHs in the nearby Large Magellanic Cloud Galaxy have shown a clear difference with previous studies and with what was observed in the Milky Way, our mother galaxy. Our satellite galaxy is rich in organic material. The findings surprised the researchers because “the previous observations in the interstellar dust of the Magellanic Large Cloud were very similar to that of the Milky Way. Our study, however, found that these organic molecules are processed and changed their composition shortly after they are expelled from the dying stars to fill the void inside the galaxy. These dying stars of our “neighbors” are much richer in carbon than the stars of the Milky Way, so they are more likely to give birth to these wide variety of organic compounds”. 

Currently, other carbon molecules, such as sugar and alcohol, have been found in the Milky Way. If appropriate tools are used these molecules can be observed even beyond our galaxy. In the future, we will be able to learn about the organic molecules that have created the universe. Current observations and models suggest that it took about a billion years for the stars to accumulate enough carbon atoms to form organic molecules. We hope the mystery solution comes with future space missions.

Large Magellanic cloud, definition and study. A-Z index of Cognitio.



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Large Magellanic cloud, definition and study. A-Z index of Cognitio.

Large Magellanic cloud