What is another standard unit for expressing the Sun-Earth distance?

What is another standard unit for expressing the Sun-Earth distance?

• A. Parsec
• B. Light-year
• C. Kilometer
• D. Astronomical unit

Answer: (D)

Distances within our solar system are most conveniently expressed in astronomical units, because this unit is tied to the Sun–Earth distance itself. One astronomical unit is the average distance from the Earth to the Sun, serving as a natural yardstick for orbits and planetary scales. It equals about 149.6 million kilometers (approximately 93 million miles), and by definition is 149,597,870.7 kilometers exactly. Parsecs and light-years, while useful for interstellar distances, are much larger scales than the Solar System: a parsec is about 206,265 AU, and a light-year is about 63,241 AU. A kilometer is perfectly valid as a unit of distance, but it becomes unwieldy for solar-system measurements due to the enormous numbers involved.

Distances within our solar system are most conveniently expressed in astronomical units, because this unit is tied to the Sun–Earth distance itself. One astronomical unit is the average distance from the Earth to the Sun, serving as a natural yardstick for orbits and planetary scales. It equals about 149.6 million kilometers (approximately 93 million miles), and by definition is 149,597,870.7 kilometers exactly.

Parsecs and light-years, while useful for interstellar distances, are much larger scales than the Solar System: a parsec is about 206,265 AU, and a light-year is about 63,241 AU. A kilometer is perfectly valid as a unit of distance, but it becomes unwieldy for solar-system measurements due to the enormous numbers involved.