by what fraction would the diameter of the moon appear shortened to an observer in a rocketship travelling at a speed of 300km/sec with respect to the moon

Question

by what fraction would the diameter of the moon appear shortened to an observer in a rocketship travelling at a speed of 300km/sec with respect to the moon

Answer 1

The answer is the Lorenz factor of √(1 - v²/c²).

Substituting actual numbers:

√(1 - 300²/300000²) ≈ 0.9999995