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Why do meteoroids glow when they enter Earth’s atmosphere?

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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.

Meteoroids glow when they enter Earth’s atmosphere due to the intense heat generated by their high-velocity entry.12

As a meteoroid travels through space and enters the atmosphere, it moves at extremely high speeds—at least 11 km per second. This rapid movement causes an energetic collision with atmospheric atoms and molecules. The friction and resistance encountered by the meteoroid convert its kinetic energy into heat.12

This heat is sufficient to vaporize and ionize the surface material of the meteoroid, as well as the surrounding atmospheric gas. The excitation of these atoms creates a luminous region that travels with the object, which we observe as a meteor, or "shooting star". Most of this energy is dissipated as heat, while a small fraction—approximately 0.1 to 1 percent—is transformed into the visible light that makes the streak appear in the sky.12