How do aerodynamic shapes form on some meteorites?

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Meteor and meteoroid The Cabin Creek meteorite, an iron (nickel-iron alloy) meteorite that was observed to fall in northwestern Arkansas on March 27, 1886. Its characteristic pattern of “thumbprint” dimples, or regmaglypts, is the result of melting and consequent ablation of its surface as it traveled through the atmosphere. The meteorite is likely a fragment of one of the M class asteroids, which show significant nickel-iron in their surface material.

Aerodynamic shapes on meteorites are formed during their high-velocity passage through Earth’s atmosphere. As a meteoroid enters the atmosphere, it experiences intense heat caused by friction with atmospheric gas molecules, which leads to the ablation or melting of its surface material.1

While most meteoroids tumble during this descent, some maintain a stable, fixed orientation similar to that of a crewed spacecraft. When a meteoroid remains in this consistent orientation throughout its flight, the surface melting and flow of material result in distinct aerodynamic shapes and flow structures on the resulting meteorite. These features are often accompanied by a dark, glassy fusion crust created by the surface melting process.1