A light-year, alternatively spelled light year (ly or lyr[3]), is a unit of length used to express astronomical distances and is equal to exactly 9 460 730 472 580.8 km, which is approximately 9.46 trillion km or …

Sep 25, 2025 · A light-year is the distance light travels in one Earth year. Learn about how we use light-years to measure the distance of objects in space.

A light-year is the distance light can travel in one year. Light is the fastest thing in our Universe traveling through interstellar space at 186,000 miles/second (300,000 km/sec).

Dec 13, 2025 · Light-year, in astronomy, the distance traveled by light moving in a vacuum in the course of one year, at its accepted velocity of 299,792,458 metres per second (186,282 miles per second).

May 28, 2020 · The light year or light-year (ly) is a unit of length that is the distance light travels in a vacuum in one Earth year. One light year is exactly 9460730472580.8 km (approximately 9.46 trillion …

May 26, 2025 · A light-year is the distance light travels in a vacuum over the course of one year. Multiply the speed of light by the number of seconds in a year, and you get the magic number: about 9.46 …

Dec 15, 2024 · Light travels at an extraordinary speed of 186,000 miles per second, covering 5.88 trillion miles in a year. This unit of measurement, the light-year, helps describe the vastness of space.

Jan 1, 2025 · So, a light-year is 5.88 trillion miles (9.46 trillion km). However, stars and nebulae – not to mention distant galaxies – are vastly farther than one light-year away.

The fastest thing that we know of is light which travels at a speed of 186,000 miles or 300,000 kilometers per second in empty space. To get an idea of how fast this is, light can travel about seven times …

Feb 17, 2024 · Put simply, a lightyear is the distance light travels in space in a year, 9.46 trillion km (5.88 trillion miles) or 63,241 AU, 0.30 parsecs. Nothing travels faster than light.