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How does frictional heating change a meteoroid during atmospheric entry?
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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.
When a meteoroid enters Earth’s atmosphere at high velocities, it collides with atmospheric gas molecules, converting its kinetic energy into intense heat. This frictional heating significantly alters the object in several ways:12
- Surface Melting and Vaporization: The heat causes the meteoroid's surface to melt and vaporize, a process known as ablation. This loss of mass often results in the creation of a luminous trail.12
- Fragmentation: Aerodynamic pressure can exceed the meteoroid's crushing strength, leading to catastrophic fragmentation.1
- Formation of Fusion Crust: For meteoroids that survive to reach the ground as meteorites, the surface melting often creates a dark, glassy exterior called a fusion crust.1
- Internal Temperature: While the surface experiences extreme heat, the interiors of larger meteoroids often remain unheated during their brief passage through the atmosphere.1
Ultimately, this release of energy destroys the vast majority of meteoroids before they reach the surface.12