Calculate the total amount of int ernal energy lost per year from earth, assuming a heat flux of 7.5 x 10-10 j m-2 s- (b) calculate the temperature of earth if the 'heat flux' had been constant over the age of the solar system but none of the heat had escaped the planet. a typical value for the specific heat of rock is cp = 1.2 × 103 j kg k-1