What do you mean by year and light year?

"Year" is a unit of time, but "light year" is not a unit of time, but a unit for measuring the space-time distance of celestial bodies in astronomy. The distance between celestial bodies in the universe is far away. If we use meters and kilometers (kilometers) as the unit of measurement, it is inconvenient to measure the distance between celestial bodies with dozens or dozens.

Light-year is a unit of length, which is used to measure the distance that light travels in a straight line in a cosmic vacuum in one year. Generally used to measure the space-time distance between celestial bodies. Literally, it refers to the distance that light travels in a straight line in a cosmic vacuum for one year, that is, 94607580800 meters. It is a unit calculated by time and the speed of light.

Extended data:

The distance between celestial bodies in the universe is very large. If it is troublesome to calculate in the most common kilometer unit, it is much easier to measure in light years. The speed of light in vacuum is about 300,000 kilometers per second, that is, 3× 108 meters per second (Julian is about 365.25 days longer, taking 65438+ 10/2000 (denoted as J2000.0) as the standard epoch), so a light year is 9.4605.

The emergence of Chinese characters began in the Zhou Dynasty. Although when I was in Tang Suzong, I changed the year to the year, but the cycle was very short, also called the year. Year is a unit of time, which has been used until now. A cycle of spring, summer, autumn and winter is called a year. In written language, words also appear from time to time, which is obviously influenced by ancient appellations.

Baidu Encyclopedia-Lightyear