Earth's temperature the sun emits energy at a rate of about 3.9 · 1026 w. at earth, this sunshine gives an incident energy flux i, of about 1.4kw m”. in this problem, you'll investigate whether any other planets in our solar system could support the sort of water-based life we find on earth. consider a planet orbiting at a distance d from the sun (and let de be earth's distance). the sun's energy flux at distance d is 7 = le(d,/d)2, because energy flux decreases as the inverse square of distance. call the plant's radius r, and suppose that it absorbs a fraction a of the incident sunlight, reflecting the rest back into space. the planet intercepts a disk of sunlight of area 7r? , so it absorbs a total power of tr’al. earth's radius is about 6400 km.