Cosmic dust did not affect Earth's climate
By analyzing ice cores from Antarctica, researchers could not detect any changes in the amount of deposited extraterrestrial dust particles over the last millennia. Accordingly, the cosmic matter, of which at least 40,000 tons patter on our planet every year, did not contribute to the end of the last ice age, explain Gisela Winckler from the Lamont-Doherty Earth Observatory in Palisades and Hubertus Fischer from the Alfred Wegener Institute for Polar and Polar Sciences Marine research in Bremerhaven.
The scientists had analyzed helium isotopes in melt water. According to the measured ratio of the isotopes, almost all of the rare 3He in the samples is of extraterrestrial origin. It comes from the solar wind, which charges the cosmic dust with it on its way through the interplanetary. According to the data, the influx of 3He remained relatively constant over the studied time span from 6800 to 29 000 years before present. It is therefore suitable as an indicator for quantitative accumulation rates of ice cores from deep wells, according to the researchers.
On the basis of the 4He values, however, the researchers did recognize a difference in the area of terrestrial dust particles between the last Ice Age and today. "Either the source areas of the mineral dust change, or the weathering processes responsible for dust production vary with the Ice Age cycle," explains Winckler.
