Light year is the distance that light travels in a year. Light year is a distance unit. It is used to describe the huge distances between stars and other celestial bodies.
Distance is the measurement of gap or length in an area between two objects or two points. Measurement units such as kilometers, meters, centimeters, millimeters are used to measure the distance. Light years is used to measure huge distances in astronomical scale.
Although the light year seems like a time unit, it is actually relative distance definition. Simply, it is like the distance traveled by a vehicle traveling at a speed of 60 km per hour.
Light travels at a speed of about 300,000 km per second. Light is so fast that it can travel around the Earth orbit 7 times. Although the light is so fast, its speed is not infinitive. Therefore, it takes time when the light travels from one point to another one. For Instance, sun rays reach the Earth in 8 minutes. The closest star to Earth, Proxima Centauri, is about 4 light years from Earth. This means that light, the fastest thing in the universe, takes more than 4 years to reach the nearest neighboring star.
The year is approximately 365 days and 6 hours, which corresponds to the earth making one complete orbit around the sun. In another words, 1 year equal to 8.766 hours. It is enough to multiply the speed of light per hour by the number of hours in a year to find out how much distance a light-year represents.
Light Speed = 1.080.000.000 km / hr.
Year = 8.766 hr.
Light Year = light speed x year = 1.080.000.000 km/hr. * 8.766 hr. ≈ 9.500.000.000.000 km
As you can see the calculations above, a light year is approximately equal to 9,5 trillion km.
The distances between several things in space are significantly large. Stars that seem remarkably close to each other are actually extremely far apart. Light years are used to understand astronomical distances, just as kilometers are used for distances between cities. This makes it possible for physicists to measure the solar system, galaxy and universe meaningfully and accurately.
