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
The Three Trillion Dollar War Times" and international best-seller and has been translated into 22 languages. The total cost of $3 trillion is comparable to that found in other studies. The Joint Economic Committee of Congress estimated that the war would cost $3.5 trillion, while the non-partisan Congressional Budget Office projected that the total cost will reach between $1.4 and $2.2 trillion. The Stiglitz-Bilmes work builds on an earlier study by Yale economist William Nordhaus, who predicted in 2002 that the war could reach $2 trillion if it went badly. Numerous economists, including James K. Galbraith of the University of Texas and Nobel Laureate Lawrence