micrometeorite


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micrometeorite

(mÿ-kroh-mee -tee-ŏ-rÿt) A cosmic dust particle of mass less than about 10–6 gram and diameter less than 0.1 mm. On impact with the Earth's atmosphere the heat absorbed by the particle from atmospheric friction is insufficient to raise it to boiling point. The ratio of heat radiated to heat absorbed is proportional to the inverse of the radius of a particle: those larger than 10–6 gram ablate and form meteors; smaller ones do not. The micrometeorite will be decelerated to a normal free-fall velocity and then drift to the surface of the Earth. On the Moon, however, no deceleration occurs and they impact the surface with the normal geocentric velocity.

micrometeorite

[¦mī·krō′mē·dē·ə‚rīt]
(astronomy)
A very small meteorite or meteoritic particle with a diameter generally less than a millimeter.
References in periodicals archive ?
X-ray and SEM examinations of the micrometeorite and the weathered crust of the meteorite revealed very similar mineral and chemical compositions of the two materials.
A RECENT EUROPEAN STUDY has confirmed that a silent cosmic rain of micrometeorites is falling on us.
Using a model of impact delivery and a known estimate of micrometeorite flux at Mercury, Bruck Syal was able to estimate how often cometary material would impact Mercury, how much carbon would stick to Mercury's surface, and how much would be thrown back into space.
For nearly four minutes, while the rocket attained its maximum altitude of 168 kilometers and descended to 116, the 'flytrap' collectors were subject to micrometeorite bombardment.
Over time an icy surface should darken due to cosmic radiation and micrometeorite impacts.
Researchers have previously suggested that small moons have been eroded away by micrometeorite impacts.
Exposed material darkens over long ages due to high-energy radiation and micrometeorite bombardment.
The researchers also identified micrometeorite damage and the breakdown of Teflon mountings, which may have left deposits on the back of the reflector.
Fortunately, 3 billion years of micrometeorite bombardments have eroded the rough flows into smooth rolling plains.
Rather, the smoothness may stem from micrometeorite bombardment.
Second, if it's punctured by a micrometeorite, the holes will be unlikely to line up in such a way that sunlight will scatter onto the primary mirror.