Question 2: Planet Mars Planetary Attribute Symbol Earth Mars Albedo a 0.29 0.25 Radius R (km) 6378 3395 Gravitational acceleration g (m/sz) 9.8 3.7 Mean distance from sun D (km) 150 x 10'5 228 x 10'5 Surface pressure Po (kPa) 101 0.6 (a) Calculate an appropriate value for shortwave solar radiation (Sm) incident at the top of the Martian atmosphere (answer in W/mzl. The corresponding value for Earth, 55 = 1360 W/mz. (b) Estimate the average surface temperature on Mars (answer in degrees Kelvin) using a suitable radiative energy balance. The greenhouse effect can be neglected for Mars. (c) Estimate the mass of the Martian atmosphere (answer in kg)