lightyear

A light-year (symbol ly) is a unit of distance that indicates how far light travels in one year. Because light moves at about 299,792 kilometers per second, one light-year is about 9.46 trillion kilometers (9.46 × 10^12 km) or about 5.88 trillion miles. A light-year is not a unit of time, nor is it a measure of size; it is a distance. In astronomy, it is convenient for expressing interstellar and intergalactic scales. One light-year equals approximately 0.3066 parsecs.

Typical uses include distances to stars, star clusters, and galaxies. For comparison: the Milky Way's diameter is about 100,000 ly; Proxima Centauri lies about 4.24 ly away; the Andromeda Galaxy is roughly 2.5 million ly distant. Light-years are larger than solar system scales; for solar system exploration, light-hours or light-minutes are sometimes used.

Popular culture: Lightyear is also the title of a 2022 animated film from Pixar Animation Studios. The film presents an origin story for Buzz Lightyear, the spacefaring character that inspired the Toy Story action figure. It was released in several markets and received mixed reviews, with praise for animation and voice acting.