The "Light Year" is a unit. It has the dimensions of length or distance, just like the inch, foot, yard, meter, furlong, mile, and kilometer. It was invented at the time in the development of...
Light travel in vacuum for approximately 300,000 km/second. Hence, the speed of light in: 1 second= 300,000 km/second 1 minute= 18 000,000 km/minute 1 hour= 1.080 x 109 km/hour 1 day= 2.592 x 1010...
Galaxies are always calculated in light years or parsecs. Most galaxies are calculated in mly of kpc (Million light years or thousand parsecs) because of the distances.
The Andromeda Galaxy is our...