How Long To Travel A Light-year (And Why)?

How Long To Travel A Light-year (And Why)?

Exact Answer: 37,200 Years (Approx)

Light-year is a unit of distance. Light-year defines the travel of light in one year. Light can travel around 300,000 km per second; the total distance that light travels in one year (365 days)  is called one light-year which is around 9.5 trillion km (6 trillion miles). This unit is to make the big calculation of distance in space easy. This unit of length came into use after 1851; when it was first introduced in a German article on astronomy.

The name of this unit has always been in the discussion as it ends with the word “year” people tend to think of it as a unit of time instead of length.

How Long To Travel A Light year

How Long To Travel A Light-Year?

For Light1 Year
For other Objects 37,200 Years Approx

The need for the light-year came because it is difficult to measure the distance with normal length units when it comes to space. The fastest object in the world is light and it travels with the approximate speed of 300,000 km per second which is 1.1 billion km per hour; the distance light travels in one year is approximately 9.5 trillion km which is a very big number to count. Light-year is used to measure the cosmic distance in space and it shows the distance covered by light in one year which is why it is called ‘light-year’. Even if we try to travel a light year in a space shuttle; which can travel on 5 miles per hour, it would still take around 37,000 years for humans to travel one light-year. 

One light-year can also be explained by its small units like light-hour, light-minute and light-second; Talking in detail, one light-hour is the distance that light travels in one hour the same way one light-minute is the distance traveled by light in one minute. The Sun is around 8 light-minutes away from the earth which means it takes only 8.3 minutes for light to travel from Sun to earth which is 150.11 million km, so it would take many years for any other objects to cover the distance from earth to sun. When The moon is just around a light-second away from earth (about 386,400 km) it still takes approximately three days for a space shuttle to reach the surface of the moon but only 1.25 seconds for light.

Why Does It Take That Long To Travel A Light-Year?

As the Light-Year describes distance in Space And space is enormous and is much bigger than our imagination; As we know that the light which we experience on earth comes directly from the sun which is more than 150 million km away from earth. light is made of photon particles which has the ability to travel with the fastest Speed of 299,792,458 km per second (or about 186,282 miles per second) which is why it takes around 499 seconds for light to cover that distance between the sun and earth. 

Through light-year it becomes easy to find out or measure the distance between the planets and the sun. As all the planets are at different distances from the sun; we can measure their proper distance by counting the time which takes for sunlight to reach them; for instance Mercury, which is 38 million km away from the Sun and also is the first planet of the solar system, it only takes 193 seconds (3.2 minutes) for light to reach Mercury from the sun; so from this time the distance from Mercury to sun can be measured as 3.2 light minutes or 0.000006123880620837039 light years. If we talk about the last planet of our solar system which is Pluto; Pluto is at the longest distance from the sun, around 5906.4 million km which is 0.000628 light years; it takes 5.5 hours for light to reach Pluto from the Sun, Just like this with the light year the distance between two objects in space can be find out.


As the Light Year describes cosmic distance. By the distance covered by light between two objects and the time it took for the same we can find out the distance between those two places in space. For example the star which is closest to earth apart from the Sun is Alpha Centauri system which has 3 stars; this star system is approximately 4.22 light years away from the earth, so by this numbers it can be said that it would take 4.22 light years for light to travel to that star from the earth. 

Although It takes around 37,200 years for a human to Travel one light year but it is said to be nearly impossible for us to travel a light year.

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Hi! I'm Nidhi.

Here at the EHL, it's all about delicious, easy recipes for casual entertaining. So come and join me at the beach, relax and enjoy the food.

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