Understanding Light Years: How Astronomers Measure Distance in the Cosmos

A closer look at the concept of light years and the calculation behind it

When we think about the distance between stars and galaxies, it’s hard to comprehend the vastness of space. The basic unit of distance in astronomy is the astronomical unit (AU), which is the average distance between the Earth and the Sun. However, when dealing with distances to stars and galaxies, the astronomical unit is far too small. Instead, astronomers use the light year, which is the distance that light can travel in one year.

What is a light year ?

A light year is the distance that light can travel in one year. It is a measure of distance used in astronomy to express the vast distances between stars and galaxies.

“A light year is not a measure of time. It is a measure of distance. It tells us how far away something is, not how long it takes to get there.” — Neil deGrasse Tyson

The properties of light

To understand how light years are calculated, it is important to understand the properties of light. Light is a type of electromagnetic radiation that travels at a constant speed of 299,792,458 meters per second (often rounded to…