The streamlined shapes of many tektites suggest a rapid movement through the atmosphere under low gravity conditions, with melting early in their formation. About 30 distinctly different shapes have been described. They start as a molten blob projected through our atmosphere, then 'freeze' into a shape as they solidify.
The shape depends on whether the initial molten blob was rotating, and the speed of rotation. The spherical and button types (common in Australites) had no or very little rotation with a fairly steady flight path direction. Their rear surfaces were more protected from heat, but the front surface, facing the flight direction, melted and was pushed towards the rear, piling up to form ridges and a rim or flange.
These 'flanged button' shapes have been copied artificially at the Corning Glass Company in America, where molten glass spheres were placed in the jetstream of a wind tunnel. The tear-drop shapes formed from stretching and breaking apart of rapidly rotating, elongated dumb-bells. Flat disks, ovals and boomerang shapes have all been found.
Copyright © Australian Museum, 2004
