Why does Earth have a glowing sodium layer high above it?

Answer: Micrometeors burn up and release sodium high above Earth

Sea salt rides storms all the way into space — Wrong. Sea spray stays far lower in the atmosphere and does not form the thin sodium layer seen from space.

Rocket launches keep leaving sodium behind — Wrong. Rockets can add trace chemicals, but they do not create Earth’s persistent global sodium layer.

Micrometeors burn up and release sodium high above Earth ✓ — Correct! Tiny meteoroids hit Earth every day. As they burn up, they release sodium atoms that collect in a thin layer about 80 to 105 kilometers up.