Planetary core has an observed magnetic field, which is believed to be generated within its metallic core. Mercury's core occupies 85% of the planet's radius, making it the largest core relative to the size of the planet in the Solar System; this indicates that much of Mercury's surface may have been lost early in the Solar System's history. Mercury has a solid silicate crust and mantle overlying a solid iron sulfide outer core layer, followed by a deeper liquid core layer, and then a possible solid inner core making a third layer. The composition of Venus' core varies significantly depending on the
The Social Conquest of Earth The Social Conquest of Earth The Social Conquest of Earth is a 2012 non-fiction book by biologist Edward O. Wilson. Wilson adapted the title of Paul Gauguin's famous mural as a theme -- "What are we?", "Where did we come from?", "Where are we going?"—for discussing his topic of eusocial behavior in several arthropod taxa and a few mammalian species, and its role in making humans as a species unique. Wilson argues, building on the paper "The evolution of eusociality" (2010) by Wilson, Martin Nowak and Corina Tarnita in "Nature", for more importance of group selection and against the idea