1. Extremely small particles of rock or metal from space that enter Earth's atmosphere; meteorites smaller than about 1 millimeter in diameter.
Usage: Plural form; singular is micrometeorite.; Used in astronomy, space science, and geology.

Examples

• Micrometeorites constantly bombard Earth's upper atmosphere.
• Scientists study micrometeorites collected from Antarctic ice to learn about the early solar system.
• The spacecraft's surface was pitted by impacts from micrometeorites during its mission.
• Micrometeorites are so small that they usually burn up completely as they fall through the atmosphere.
• Researchers found micrometeorites embedded in deep-sea sediments.
• The accumulation of micrometeorites on the Moon's surface has been studied by lunar missions.