A laboratory model of splash-form tektites

available online at http://meteoritics.org 1331 © Meteoritical Society, 2003. Printed in USA. A laboratory model of splash-form tektites Linda T. ELKINS-TANTON,1, 2* Pascale AUSSILLOUS,3 José BICO,4 David QUÉRÉ,3 and John W. M. BUSH5 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA 2Department of Earth and Planetary Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA 3Laboratoire de Physique de la Matière Condensée, UMR 7125 du CNRS, Collège de France, 75231 Paris Cedex 05, France 4Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA 5Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA *Corresponding author. E-mail: [email protected]) (Received 21 November 2002; revision accepted 2 September 2003) Abstract–Splash-form tektites are generally acknowledged to have the form of bodies of revolution. However, no detailed fluid dynamical investigation of their form and stability has yet beenSplash-form tektites are generally acknowledged to have the form of bodies of revolution. However, no detailed fluid dynamical investigation of their form and stability has yet been undertaken. Here, we review the dynamics and stability of spinning, translating fluid drops with a view to making inferences concerning the dynamic history of tektites. We conclude that, unless the differential speed between the molten tektite and ambient is substantially less than the terminal velocity, molten tektites can exist as equilibrium bodies of revolution only up to sizes of 3 mm. Larger tektites are necessarily non-equilibrium forms and so indicate the importance of cooling and solidification during flight. An examination of the shapes of rotating, translating drops indicates that rotating silicate drops in air will assume the shapes of bodies of rotation if their rotational speed is 1% or more of their translational speed. This requirement of only a very small rotational component explains why most splash-form tektites correspond to bodies of revolution. A laboratory model that consists of rolling or tumbling molten metallic drops reproduces all of the known forms of splashform tektites, including spheres, oblate ellipsoids, dumbbells, teardrops, and tori. The laboratory also highlights important differences between rolling drops and tumbling drops in flight. For example, toroidal drops are much more stable in the former than in the latter situation.