What is a Light Year?

Light year is a unit of length. It is used to measure the distance that light travels along a straight line in the cosmic vacuum for one year ^[1] . It is generally used to measure the space-time distance between celestial bodies. It literally means that the light is along a straight line in the cosmic vacuum The distance traveled over a year is 9,460,730,472,580,800 meters, which is a unit of time and the speed of light.

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In a Julian year (defined as 365.25 days), in

Light years are generally used to measure large distances, such as the sun and another

Prior to 1676, people generally believed in light

The exact length of light years: calculated as 1 year = 31556925.9747 seconds, speed of light = 299,792,458 meters per second, 1 light year = 9 460 730 472 580.8 kilometers. (9.4607 × 10 ¹² _km )

Conversion to other commonly used length units in astronomy:

Light by

Because it carries the word "year", it is often mistaken for a unit of time, so that it is sometimes misused. For example, in some popular songs, it may be misused to compare the long time, such as "in a blink of an eye / instantaneous, one light year."