Structure of the Earth decay of radioactive elements, and freezing of the inner core. Structure of the Earth The internal structure of the Earth is layered in spherical shells: an outer silicate solid crust, a highly viscous asthenosphere and mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. Scientific understanding of the internal structure of the Earth is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanoes or volcanic activity, analysis of the seismic waves that pass through the Earth, measurements of
Chaotian (geology) the Mundrabilla iron meteorite of Western Australia using the argon method determined an age of 4,570 ± 60 million years ago. The proposed collision with Theia, leading to the formation of the Moon, is estimated to have occurred 4.527 billion years ago. Outgassing and differentiation of the earth in an iron-rich core and mantle may have been completed 4.45 billion years ago. Chaotian (geology) In the geologic record the Chaotian eon or era is unofficially proposed to denote the time preceding the solidification of the Earth's crust and the formation of Earth's moon, it is the earliest era within the