A light year is a measure of distance. How many meters are there in 1.00 light year? An astronomical unit is the average distance
The Correct Answer and Explanation is:
Answer:
There are approximately 9.461 × 10¹⁵ meters in 1.00 light-year.
Explanation
A light-year is a unit of distance used in astronomy to describe the vast expanses between stars and galaxies. It represents the distance that light travels in a vacuum in one year. Since light moves incredibly fast—at about 299,792,458 meters per second (m/s)—the total distance it covers in a year is immense.
To calculate how far light travels in a year, start by determining how many seconds are in one year. A standard (non-leap) year has 365.25 days, accounting for leap years:
- 365.25 days/year × 24 hours/day × 60 minutes/hour × 60 seconds/minute = 31,557,600 seconds/year
Now multiply the speed of light by the number of seconds in a year:
- 299,792,458 m/s × 31,557,600 s ≈ 9.461 × 10¹⁵ meters
This means that light travels nearly 9.5 trillion kilometers—or more precisely, about 9.461 petameters (Pm)—in one year.
The light-year is used because using conventional units like kilometers or miles becomes unwieldy when describing interstellar distances. For example, the nearest star system, Alpha Centauri, is about 4.37 light-years away. Expressing that in kilometers or meters would result in very large and hard-to-comprehend numbers.
An astronomical unit (AU) is another unit of distance commonly used in astronomy. It represents the average distance from the Earth to the Sun, which is approximately 1.496 × 10¹¹ meters. This unit is more suitable for measuring distances within the solar system, such as between planets.
To compare the two:
1 light-year ≈ 63,241 AU
Understanding both light-years and astronomical units helps in grasping the immense scale of the universe and provides context for the distances between celestial objects.
