From Latin infinitus, infinite is what does not have (nor can have) term or end . The concept is used in various fields, such as math , the philosophy and the astronomy .
Ordinal numbers are those that indicate the position of an element in a ordered sequence that extends to infinity . In general it can be said that numbers they are always infinite, since their succession finds no limit. In other words: if one begins to count (1, 2, 3 ...), he must decide when to stop because, otherwise, there will always be a number that follows the last one.
He symbol infinity looks like the lemniscata curve . It is not clear what its origin is, although it is believed that it could come from very old religious or alchemical symbols.
In everyday language, the use of the concept of infinity does not necessarily imply something without final, but can be used to refer to something that is presented in large numbers or whose dimensions are very considerable. For example: “The possibilities offered by this agreement are endless”, "The engine allows you to render infinite detail on any device thanks to its revolutionary algorithm".
Infinity can also be a imprecise place, either because of its remoteness or vagueness : "When he looked through the lock, he noticed that the corridor was lost in infinity".
The idea of infinity implies the existence of various paradoxes. One of the best known refers to a infinite hotel . This metaphor, proposed by the German mathematician David Hilbert (1862-1943), speaks of the existence of a hotel that can accept more guests even if it is full, as it contains infinite rooms.
The Olbers paradox
As noted, say that the Universe it is infinite contradicts the darkness of the sky at night, and this is the basis of Olbers' paradox; it ensures that if the cosmos if it were really infinite, then any line drawn from the eyes of a terrestrial towards the sky should at least pass a star, which would show a constant brightness. Physicist and astronomer Whilhelm Olbers, a native of Germany, recorded these ideas during the 1820s.
For there to be a paradox, first of all there must be a minimum of two apparently valid reasonings that, when applied to the same subject, return opposite results. In this case, if the theory of a sky always bright then it is the reasoning that opposes the one used by astronomers who accept a space Black among the stars.
Since the seventeenth century, long before the birth of Olbers, several astronomers warned of this paradox; such was the case of Johannes Kepler, also German, who used it to complement his studies about the Universe and its supposed quality of infinity; In the early 1700s, Edmund Halley, from Great Britain, tried to justify the fact that there were dark areas in the sky by proposing that, although the Universe is indeed infinite, stars They do not have a uniform distribution.
He job The latter served as inspiration for Jean-Philippe Loys de Chéseaux, Swiss, who studied the paradox and suggested two possibilities: the universe is not infinite; it is, but the intensity of the light coming from the stars decreases rapidly with distance, perhaps because of some space material that absorbs it.
Olbers, similarly, proposed the presence of some matter that would block much of the light of the stars, in their attempt to explain the dark spaces. At present, it is believed that this solution is not possible, since such matter should be heated over time to shine as brightly as a star.