The light-year is a unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometres (9.46×1012 km) or 5.88 trillion miles (5.88×1012 mi). 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 non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years) which derives from astrometry: it is the distance at which one astronomical unit subtends an angle of one second of arc.
hey guys, I'm new to physics .. and to be frank it seems scary. :-p
anyways i was wondering if anyone could help me with this:
The diameter of milky way is 1.0 *10^5 lightyears (ly). The distance to Andromeda is about 2.0 million ly. If a scale model represents the milky ways and andromeda...
How is it that we are able to see galaxies that are billions of light years away considering that we are presumably traveling from the same origin? Would that somehow mean that the distance between the two galaxies was growing at a rate greater than the speed of light? If not, why not?
The...