"Space Exploration and Plate Tectonics"
The second half of the
20th century saw two historic
scientific developments: the achievment
of space flight and the emergence of the theory of plate tectonics. These superficially independent events are
much more closely related than most scientists realize.
This lecture will summarize major
discoveries from space research, both terrestrial
and extraterrestrial, and demonstrate their relation to plate tectonic
theory. Examples will include
sea-surface altimetry, direct measurement of plate rigidity and plate
motion,
remote sensing of continental areas, discovery of folded mountains on
Venus (a
planet with no plates), and evidence that even small bodies like the
Moon have
undergone early global differentiation, forming crusts analogous to the
continental crust of the Earth. Plate
tectonic theory has been essentially confirmed by space research, but
it has
also been found at least incomplete, if not incorrect, in several
respects.