Light-year Light-year The light-year is a unit of length used to express astronomical distances and measures about 9.46 trillion kilometres or 5.88 trillion miles. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Because it includes the word "year", the term light-year is sometimes misinterpreted as a unit of time. The light-year is most often used when expressing distances to stars and other distances on a galactic scale, especially in nonspecialist and popular science publications. The unit most commonly used in professional astrometry is the parsec
Lotus 1-2-3 cartridges but otherwise identical. By early 1984 the software was a killer app for the IBM PC and compatibles, while hurting sales of computers that could not run it. "They're looking for 1-2-3. Boy, are they looking for 1-2-3!" "InfoWorld" wrote. Noting that computer purchasers did not want PC compatibility as much as compatibility with certain PC software, the magazine suggested "let's tell it like it is. Let's not say 'PC compatible,' or even 'MS-DOS compatible.' Instead, let's say '1-2-3 compatible.'" PC clones' advertising did often prominently state that they were compatible with 1-2-3. An Apple II software company promised