Stars - Light-Year Definition

This section focuses on understanding the concept of a light-year, a crucial unit for measuring vast distances in space, particularly the distances to stars.

What is a Light-Year?

A light-year is the distance that light travels in one year. Because light travels at a constant speed, this provides a convenient way to express the immense distances between stars.

Calculating the Distance in Meters

The value of one light-year is approximately $9.5 \times 10^{15}$ meters. This is a very large number!

Key Information

• Definition: The distance light travels in one year.
• Value: $9.5 \times 10^{15}$ meters
• Use: Measuring distances to stars and galaxies.

Table: Light-Year Conversions

Unit	Value
Light-Year	$9.5 \times 10^{15}$ m
Light-Year	$9.461 \times 10^{12}$ km
Light-Year	$6.324 \times 10^{9}$ miles

Understanding the light-year is fundamental to comprehending the scale of the universe. It allows us to express distances to stars in a more manageable way than using kilometers or miles.