A Direct Measurement of the Terrestrial Mass Accretion Rate of Cosmic Dust

Abstract

The mass of extraterrestrial material accreted by the Earth as submillimeter particles has not previously been measured with a single direct and precise technique that samples the particle sizes representing most of that mass. The flux of meteoroids in the mass range 10(-9) to 10(-4) grams has now been determined from an examination of hypervelocity impact craters on the space-facing end of the Long Duration Exposure Facility satellite. The meteoroid mass distribution peaks near 1.5 x 10(-5) grams (200 micrometers in diameter), and the small particle mass accretion rate is (40 +/- 20) x 106 kilograms per year, higher than previous estimates but in good agreement with total terrestrial mass accretion rates found by geochemical methods. This mass input is comparable with or greater than the average contribution from extraterrestrial bodies in the 1-centimeter to 10-kilometer size range.

Prognostic Value of Cardiovascular Magnetic Resonance and Single-Photon Emission Computed Tomography in Suspected Coronary Heart Disease: Long-Term Follow-up of a Prospective, Diagnostic Accuracy Cohort Study

“…While these 39 collections include particles exhibiting different degrees of thermal alteration (ranging from 40 unmelted particles to cosmic spherules) and weathering, it has been possible to establish 41 their general properties before aerobraking (Jessberger, et al, 2001, Kohout, et al, 2014, 42 Taylor, et al, 2012. IDPs size and composition have also been investigated by particle 43 detectors on board orbital spacecraft such as the Long Duration Exposure Facility (LDEF) 44 (Love and Brownlee, 1993) and the MIR Space Station (Hörz, et al, 2000), where the major 45 difficulty has been characterising the effect of the high speed impacts (v >11 km s -1 ) on the 46 exposed materials (e.g. aluminium, aerogel).…”

Estimate of the neutral atoms' contribution to the Mercury exosphere caused by a new flux of micrometeoroids

“…The first is based on the data from Love & Brownlee (1993) (as done in BM), while the second is based on data by Grün et al (1985), hereafter LB and G respectively. Moreover, we give different values of the vapor production rates, taking into account the different balance between asteroidal and cometary sources of dust particles (Wiegert et al 2009;Dermott et al 2002).…”

Cosmic dust in space and on Earth

“…Despite their small size, it is estimated that ~40 000 tonnes of extraterrestrial material arrives at the Earth every year in the form of dust (Love & Brownlee 1993), greatly outweighing the ~50 tonnes that arrives as larger meteorites (Zolensky et al 2006). Approximately 90% of this dusty material is thought to be vaporized as it enters the atmosphere, yet this still leaves a large mass of material reaching the surface and being potentially available for study (Taylor et al 1998).…”