Light-year: Unit of Astronomical Distance
A light-year is defined as the distance that light travels in a vacuum during one Julian year (365.25 days).
This unit is commonly used in astronomy and other scientific fields to express the immense distances between astronomical objects such as stars, galaxies, and other celestial bodies.
Despite the name containing "year," which relates to time, a light-year specifically measures length or separation, not duration. It quantifies how far light can travel in that time frame.
Therefore, a light-year is a unit of distance.
- Option 1: Intensity of light - Incorrect. Intensity relates to brightness.
- Option 2: Distance - Correct. This is the definition of a light-year.
- Option 3: Mass - Incorrect. Mass is the amount of matter in an object.
- Option 4: Time - Incorrect. While based on a year, it measures distance traveled *in* that time.
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