Author Question: Venus and Mars orbit the Sun at average distances of 0.72 AU and 1.52 AU, respectively. What is the ... (Read 98 times)

storky111 · **on:** Jul 14, 2018

Venus and Mars orbit the Sun at average distances of 0.72 AU and 1.52 AU, respectively. What is the solar flux at each planet?

What will be an ideal response?

Question 2

Venus has a planetary albedo of 0.8, and Mars has an albedo of 0.22. Using the answer to part (a), determine the effective radiating temperatures of these planets.

What will be an ideal response?

Question 3

if the two bodies in part (a) were the same size, what would be the ratio of the heat emitted by the hotter object to the heat emitted by the colder one?

What will be an ideal response?

bobsmith · **Reply #1 on:** Jul 14, 2018

Answer to Question 1

Inverse Square Law: S = S0(r0/r)
Given: SEarth= 1370 W/m2
rEarth = 1 AU
rVenus = 0.72 AU
rMars = 1.52 AU

Venus: SVenus = SEarth ( rEarth / rVenus)2
SVenus = 1370 W/m2 (1 AU/ 0.72 AU)2
SVenus 2642.8 W/m2

Mars: SMars = SEarth ( rEarth / rMars)2
SVenus = 1370 W/m2 (1 AU/ 1.52 AU)2
SVenus 593.0 W/m2

Answer to Question 2

Effective Radiating Temp:
Given: Te4 = S(1-A)/4
AVenus= 0.8
AMars = 0.22

Venus: Te=(SVenus/4)(1-AVenus)1/4
Te=(2642.8 W/m2 /4 (5.67 10 8 W/m2/K4)(1-0.

1/4
Venus Te = 219.7 K

Mars: Te=(SMars/4)(1-AMars)1/4
Te=(593.0 W/m2 /4 (5.67 10 8 W/m2/K4)(1-0.22)1/4
Mars Te = 212.5 K

Answer to Question 3

Stefan-Boltzmann Law: