Question

One parsec is defined as ______.

Options

• The distance light travels in one year

• The average distance between Earth and the Sun

• The distance at which 1 AU subtends an angle of 1 arcsecond

• One thousand astronomical units

Answer 1

One parsec is defined as the distance at which 1 AU subtends an angle of 1 arcsecond.

Explanation:

The word "parsec" comes from "parallax second." It is the distance at which the radius of Earth's orbit (1 AU) subtends an angle of 1 arcsecond. 1 parsec = 3.08 × 10¹⁶ m.