MICROMETEORIC DUST FROM OUTER SPACE. I began this blog marveling (here) that traces from the Big Bang caused radio static today on earth. So I marveled to read that micrometeoric dust which was in existence before the formation of the sun is still striking the earth.
This wikipedia entry defines a meteorite as: “a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the Earth’s atmosphere and impact with the Earth’s surface or that of another planet.” A micrometeorite is a dust-sized meteorite.
This article in the Economist explains the origins of micrometeorites (or “micrometeoric dust”): “About 4.6 billion years ago, when the sun was formed by the coalescence of dust, other clumps of dusts formed planets and asteroids. In planets, that dust became rock, but in many asteroids the dust remains dust….a small fraction of the dust eventually falls to earth as micrometeorites.”
About 6 tons of micrometeorites arrive at earth each day—an average of one particle per square meter each year. This dust was not part of the coalescence of dust which became the sun. Rather, it has existed since before the formation of the sun.