|
|
Post by lenlenlen1 on Oct 23, 2018 19:44:31 GMT
Light Years describes BOTH distance AND time. Duh! When you use that term with a scientist he/she immediately understands both the length of time and distance. J/S ^ that's a Lucasian misconception. A Light-year like a parsec is a unit of length commonly employed to express astronomical distances. It's about 9.5 trillion kilometres (5.9 trillion miles). IAU defines light-year as distance that light travels in vacuum space in one (Julian calender) Earth year (365.25 days). Light travels a lot slower through objects like water etc. Only way to save this would be to say that there is no space and time, there is only the fabric of spacetime.  Yes, light travels slower through different objects (and not at all in some!). BUT in the vacuum of space, assuming no obstructions, the fastest speed that can be achieved is that of light.
So, if I say something is a light year away you know that nothing can ever get there any sooner than a year from now. That statement has measured both space and the time that it takes to get there. Whether or not that's 100% accurate, its something that easily understood by the layman. It takes a year to get there.
|
|