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 ?
Scientists estimate that 100 billion micrometeorites fall to Earth each year, about one per square meter.
The laboratory investigations included magnetic separation of the micrometeorites, X-ray detection of the micrometeorites and weathered crusts, electron microprobe determination of their mineral composition, SEM semiquantitative analysis of micrometeorites, and microscopic examination in transparent and reflected light.
There was a popular belief that micrometeorites could be found on urban roofs, but now it seems to be true.
Because rays don't last very long before they're erased by the steady rain of micrometeorites and space weathering, they're the telltale marks of relative youth in craters.
Evidence of an extraterrestrial object striking Earth at the height of the last ice age comes not from a crater in the ground, but from the micrometeorites embedded in the tusks of creatures grazing the Alaskan tundra when the event occurred.
Take a magnet and put it close to the black specks, if any move towards the magnet or stick to it there is a good chance they are micrometeorites, tiny bits of dust from space that have been washed out of our atmosphere by the rain
For STS-116, the ICC was specially configured to carry a variety of payloads, ranging from Service Module Debris Panels that will protect that space station segment from micrometeorites in the future, to a Department of Defense payload set to eject three micro-satellites upon the shuttle's undocking from the ISS.
Those boot marks will fade in a few million years as micrometeorites grind them into the dust, but signs of our presence, including the alien artifacts we left, will be detectable for as long as there is an Earth and a Moon.
Space radiation and micrometeorites are also potential threats facing lunar residents.
The micrometeorites would pound the surface and ultimately become incorporated into deeper layers of the moon.
Because rays don't last very long before they're erased by the steady rain of micrometeorites, they're the telltale marks of relative youth in craters.
Hemenway of Dudley Observatory pioneered studies like this one, but the origins of many micrometeorites remain puzzling.