How Long Is One Light Year

When we use powerful telescopes to look at distant objects in space we are actually looking back in time.

How long is one light year. The light year is a unit of length used to express astronomical distances and measures about 9 46 trillion kilometres 9 46 x 10 12 km or 5 88 trillion miles 5 88 x 10 12 mi. D c t 2 9979 10 8 m s 3 1557 10 7 s 9 4605 10 15 meters. And a light year is 63 241 astronomical units 1 astronomical unit or au is the average distance from the earth to the sun. As defined by the international astronomical union iau a light year is the distance that light travels in vacuum in one julian year 365 25 days.

Latoya stevens answer a light year is defined as the distance that light can travel in 1 year. What is a light year and how long is 1 light year. To obtain an idea of the size of a light year take the circumference of the earth 24 900 miles lay it out in a straight line multiply the length of the line by 7 5 the corresponding distance is one light second then place 31 6 million similar lines end to end. That is a 6 with 12 zeros behind it.

A light year is 5 878 625 373 183 6 miles. But a light year isn t the. It is the total distance that a beam of light moving in a straight line travels in one year. We can calculate this by multiplying the speed of light by 1 year or 3 1557 10 7 seconds to find the distance.

Looking back in time. A light year is a measurement of distance and not time as the name might suggest. One light year is about 6 trillion miles 9 trillion km. A light year is the distance a beam of light travels in a single earth year or 6 trillion miles 9 7 trillion.