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
Innovation and Its Discontents Innovation and Its Discontents Innovation and Its Discontents: How Our Broken Patent System Is Endangering Innovation and Progress, and What To Do About It is a book () by Adam B. Jaffe and Josh Lerner. Princeton University Press published the book in 2004. The authors of the book outline changes made to the patent system in the United States in the late 1980s and early 1990s which they say has led to a situation in which patents have become extremely powerful economic weapons, and are being issued irresponsibly and at an unreasonable rate. The end result, the authors claim, is