Question 2 (a) What are the four main sources of energy in the solar system? [4] (b) Which of these is presently responsible for the internal heat in (i) the Earth, (ii) Jupiters moon Io? [3] (c) Venus is of a similar size to Earth, and its surface shows evidence of extensive volcanic activity. Given that it has no moon and that its day is longer than its year, comment on the likely contribution of these mechanisms to the heat in the planets interior. [10] (d) Jupiters satellite Europa has an albedo of 0.64. Calculate its effective temperature, assuming that it is a perfect black body. [6] (e) The actual mean surface temperature of Europa is about the same as its effective temperature. Together with the high albedo, explain what this implies about its exterior. [4].