At an average opposition, the Earth and Mars are separated by 0.52 AU. Suppose an astronom...

At an average opposition, the Earth and Mars are separated by 0.52 AU. Suppose an astronomer observes Mars at opposition and that seeing blurs the images to a resolution of 1.0 seconds of arc. What is the smallest surface feature the astronomer would be able to resolve on Mars? How does this size compare with the diameter of Mars? (You will need the small angle equation, Equation 3.1, to do this problem.)

Equation 3.1 The Small Angle Equation Equation 3.1 can be used to calculate the angular diameter of a body if its linear diameter and distance are known. For example, Venus has a linear diameter of 12,100 km. What is its angular diameter when it is at a distance of 5 × 107 km? (This is approximately the distance between Earth and Venus when they are closest to one another.) Using 12,100 km for D and 5 × 107 km for d, Equation 3.1 gives

= 50 seconds of arc