light-year

The concept from light-year it tends to be confusing. The presence of the term year causes many people to associate the expression with a temporal unit. Light year, however, is a measuring length which is used in the field of astronomy, and for this reason we do not speak of "taking a light year" but of "being one light year from."

Specifically, a light year is the distance what travels the light in the void in the span of a year. Since light travels 299 792 458 meters per second in a vacuum, a light year is an enormous distance: it is equal to 9 460 730 472 580.8 kilometers.

As can be seen, the use of the notion of light years allows working with simpler figures when distances are very large, as occurs between planets and other stars. Expressing distances as 40 or 200 light years, for example, would require many, many digits if units such as meters or even kilometers were to be used.

Take the case of planet Earth about Next Centauri, the star that is closest to the Sun. According to astronomers, the Land It is located about 4.22 light years from Next Centauri. This means that it takes 4.22 years for light to travel the distance between our planet and the aforementioned star. In this way, if a person observes today, from the Land, the light that emits Next CentauriYou are actually seeing the light that came out more than 4 years ago from the star. Yes Next Centauri, for some reason, ceases to exist and emit light, in the Land it would take us more than four years to notice their disappearance.

It should be noted that when the distances are smaller, similar units can be used as light minutes or light seconds.

The light minute is, as can be deduced, the distance that a electromagnetic wave over the course of one minute, which is equivalent to 17,987,547,480 meters. Among the astronomical distances that are usually expressed using this unit (instead of light year) are that of certain space probes and that between the Sun and Earth (approximately 8.31 light minutes). In the field of astronomy, the light minute is very useful to indicate the delay that can exist between two given points.

The distance expressed by the second light, for its part, is 299 792 458 meters. Is Unit measurement is used to refer to the distance between our planet and certain celestial bodies, such as the Moon (1.2 light seconds), the Sun (500 light seconds), Alpha Centauri (137 million light seconds), Pluto (20,000 light seconds) and the Andromeda galaxy (80 billion light seconds), among many others.

This light-year alternative is suitable for measurement of distances within the Solar System, as long as they are not less than the diameter of Jupiter. In the calculation of intergalactic distances, the light year must be used, or the parsec (arc second parallax), while for intergalactic there is the megaparsec (a multiple of the parsec, which is equivalent to about 3.26 million light years).

Outside the scope of astronomyIt is common to use this unit of measurement in a figurative sense, to make qualitative comparisons between people or products with the intention of accentuating the great distance that exists between the different elements. Let's look at some example sentences: "I would like my student to go directly to the next year, since she is light years away from her classmates and I fear that she will get bored to the point of frustration", "Between these two televisions there is no point of comparison, since their technologies are light years apart".