If the Sun- Earth separation were 10 AU instead of 1 AU, what would the flux of sunlight (energy per second per square meter)be at the Earth, compared to what it is today?

Question

Quizplus · Accepted Answer

The flux of sunlight decreases with the square of the distance from the Sun. Since the Sun-Earth separation is 10 times larger than it is today (from 1 AU to 10 AU), the distance from the Sun is squared to get the reduction in flux. So (1/10)^2 = 1/100, meaning the flux of sunlight would be 100 times less than what it is today.

If the Sun- Earth Separation Were 10 AU Instead of 1