Geology of solar terrestrial planets
![The inner planets. From left to right: Mercury, Venus, Earth, Mars and terrestrial dwarf planet, Ceres (sizes to scale)](/Images/godic/202501/24/5_Terrestrial_planets_size_comparison0024.png")
![Artist's conception of a protoplanetary disk](/Images/godic/202501/24/Protoplanetary-disk0024.jpg")
![Mercury’s Caloris Basin is one of the largest impact features in the Solar System.](/Images/godic/202501/24/Caloris_basin_labeled0024.png")
![The so-called “Weird Terrain” was formed by the Caloris Basin impact at its antipodal point.](/Images/godic/202501/24/Mercury's_'Weird_Terrain'0024.jpg")
The geology of solar terrestrial planets mainly deals with the geological aspects of the four terrestrial planets of the Solar System, Mercury, Venus, Earth, and Mars, and one terrestrial dwarf planet, Ceres. Only one terrestrial planet, Earth, is known to have an active hydrosphere.