Measurements of thermospheric composition by the Esro 4 gas analyzer reveal a permanent increase of exospheric temperature at high latitudes. It is argues that the required energy is ultimately derived from the solar wind and that 5¿10-4 of the total solar wind flux intercepted by the magnetosphere of the earth will maintain the observed temperature increase. Heating of a planetary upper atmosphere by solar wind will be proportional to the cross-sectional area of the magnetosphere of the planet and the leakage rate of solar wind energy into the atmosphere. It is estimated that the ratio of heat input from solar wind with respect to the EUV heat input will be about 20 times higher on Jupiter than it is on earth is similar leakage rates at both planets are assumed. The solar wind may thus contribute to the high temperatures observed in the Jovian thermosphere.