The current standard theory of the origin of the Moon is that the Earth was hit by a giant impactor the size of Mars causing ejection of iron poor impactor mantle debris that coalesced to form the Moon. But where did this Mars-sized impactor come from? Isotopic evidence suggests that it came from 1AU radius in the solar nebula and computer simulations are consistent with it approaching Earth on...

The current standard theory of the origin of the moon is that the earth was hit by a giant impactor the size of Mars causing ejection of iron poor impactor mantle debris that coalesced to form the moon. But where did this Mars-sized impactor come from? Isotopic evidence suggests that it came from 1AU radius in the solar nebula while computer simulations are consistent with it approaching earth ...

Although the information set out here focuses (because of their market leading positions) on the Andersen Cascade Impactor (ACI) and Next Generation Impactor (NGI), all multistage cascade impactors operate on the same principle: size fractionation on the basis of inertial impaction. Instruments such as the ACI and NGI consist of a series of stages each made up of a nozzle plate, with a specific...

The Rochechouart impact crater in the French Massif Central, has a diameter of 20 25 km [1] and an age of 250 my [2]. The cater is deeply eroded, down to the crater floor. Impact melt outcrops can be found in different parts of the crater [3]. The type of impactor that produced Rochechouart crater is still not clear. The first proposal of an IIA iron asteroid was based on the abundance of some ...

One of the difficulties of the current giant impact model for the origin of the Moon is to explain the marked similarity in the isotopic compositions and the substantial differences in the major element chemistry. Physics of shock heating is analyzed to show that the degree of heating is asymmetric between the impactor and the target, if the target (the proto-Earth) had a magma-ocean but the im...

The objective of this work was to investigate the ability of the Wagner-Leith passive aerosol sampler to measure indoor exposures over periods of 24 hours to 2 weeks. An automated analysis technique was developed so that lower aerosol concentrations could be sampled over shorter time periods. A test of the new analytical method against a manual method showed good agreement. The passive sampler ...