Venus - Venus (0.7 AU) is of comparable mass to the Earth (0.815 Earth masses), and, like Earth, possesses a thick silicate mantle around an iron core, as well as a substantial atmosphere and evidence of internal geological activity, such as volcanoes. However, it is much drier than Earth and its atmosphere is 90 times as dense. Venus has no natural satellite. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere. Although no definitive evidence of current geological activity has yet been detected on Venus, its substantial atmosphere and lack of a magnetic field to protect it from depletion by the solar wind suggest that it must be regularly replenished by volcanic eruptions.