How can I convert Lightyears to Kilometers?
Multiply by 9,460,730,472,580.8 – or about 9.46 trillion if you'd rather not carry thirteen digits around. That's the distance light covers in a Julian year of 365.25 days, at 299,792.458 km a second.
The centre of the Milky Way is about 26,000 light years away, which is roughly 2.5 × 10¹⁷ km.
A light year is a distance, not a time, whatever the films say.
What is a lightyear?
A lightyear is a unit of measurement used in astronomy to describe vast distances in space. It represents the distance that light travels in one year, which is approximately 5.88 trillion miles or 9.46 trillion kilometers. The term "lightyear" is derived from the fact that light, which travels at a speed of about 186,282 miles per second (299,792 kilometers per second), can cover an incredible distance in the span of a year.
Light has a finite speed, so a galaxy a billion lightyears away is seen as it was a billion years ago. That is how astronomers look back at the early universe – the farther the galaxy, the older the picture.
What is a kilometer?
A kilometer is 1,000 meters, or about 0.621 miles. 'Kilo' is the Greek-derived prefix for a thousand. It is the unit for road distances nearly everywhere except the US and UK, which still use miles.
A kilometer is about 3,281 feet or 39,370 inches. At a walking pace of 5km/h it takes about 12 minutes to cover.
Going from kilometers to meters just means moving the decimal point three places. A mile has to be broken into 1,760 yards or 5,280 feet first, and neither of those is a round number of anything.