Venus may have Earth-like lithospheric thickness and heat flow

Poor old Venera 9, the Soviet Union's Venus lander, separated from its orbiter and made a hot, violent descent through the dense Venusian atmosphere on October 22, 1975, landing hard on a circular shield designed to crumple and absorb the impact. It only survived the intense surface conditions for 53 minutes, transmitting data regarding clouds, light irradiance, temperature and atmospheric chemistry, as well as the first image ever taken of the surface of another planet. And then it died. But it...