Plate tectonics conserves angular momentum

Comment on "Intermittent plate tectonics?".

Silver and Behn (Reports, 4 January 2008, p. 85) proposed that intermittent plate tectonics may resolve a long-standing paradox in Earth's thermal evolution. However, their analysis misses one important term, which subsequently brings their main conclusion into question. In addition, the Phanerozoic eustasy record indicates that the claimed effect of intermittency is probably weak.

Afrotheria: plate tectonics meets genomics.

A frotheria is one of the most remarkable hypotheses in mammal evolution. It suggests that one-third of the orders of placental mammals form an ancient group that evolved on Africa when that continent was isolated from others through plate tectonics (1). Although this hypothesis has been predicted by molecular clock studies (2), evidence for it has emerged only in the last 3 years from phylogen...

Angular Momentum

Angular Momentum in Chemistry

Noting that current chemical theory is based almost exclusively on electronic energy and spin variables the equal importance of orbital angular momentum is explored in this paper. From its classical definition the angular momentum of electrons in an atom is shown to obey Laplace’s equation, which automatically leads to discrete values in terms of spherical harmonics. This analysis assumes a con...

From Continental Drift to Plate Tectonics

SINCE THE l6TH CENTURY, CARTOGRAPHERS HAVE NOTICED THE jigsaw-puzzle fit of the continental edges. Since the 19th century, geologists have known that some fossil plants and animals are extraordinarily similar across the globe, and some sequences of rock formations in distant continents are also strikingly alike. At the turn of the 20th century, Austrian geologist Eduard Suess proposed the theor...