Introduction: We have used the Ansys Inc. AUTODYN ® software [1] to hydrodynamically model small particle impacts into aluminium (Al) foil, under the conditions of the Stardust encounter with comet 81P/Wild 2 [2] (i.e., normal incidence, 6 km s -1 ). We compare results of impact models, based on carefully defined particle structures, with three-dimensional (3D) crater shapes reported from Stard...

[1] Present‐day accumulation in the north polar layered deposits (NPLD) is thought to occur via deposition on the north polar residual cap. Understanding current mass balance in relation to current climate would provide insight into the climatic record of the NPLD. To constrain processes and rates of NPLD resurfacing, a search for craters was conducted using images from the Mars Reconnaissance ...

The dynamics of a water jet on a flat free surface are investigated using a nanosecond pulsed laser for creating an oscillating bubble with different depths beneath the free surface. A thin jet is shown to deform a crater surface resulted from surface depression and cause a circular ring-shaped crater on the connection surface between the crater of surface depression and the thin jet. The colla...

Lunar impact craters are important for studying lunar surface morphology because they are the most typical morphological units of the Moon. Impact crater descriptive indices can be used to describe morphological features and thus provide direct evidence for both the current state and evolution history of the Moon. Current description methods for lunar impact craters are predominantly qualitativ...

[1] Pedestal craters on Mars are defined by an outwardfacing scarp forming a plateau perched tens of meters above the surrounding terrain. Their origin has been attributed to impact armoring of the surface and subsequent removal of inter-crater terrain by either eolian deflation or sublimation of an ice-rich substrate. We identified 2696 pedestal craters between 60 N and 60 S latitude; 98% are ...

BACKGROUND AND OBJECTIVE Previous investigations have reported evidence of wavelength dependence on cortical bone ablation. This study used mid-infrared laser wavelengths generated by a free electron laser (FEL) and mass removal measurements to further examine the ablation efficiency of a wavelength (2.79 microm) not previously reported and three wavelengths (2.9, 6.1, and 6.45 microm) previous...

Colonization of novel habitats is typically challenging to organisms. In the initial stage after colonization, approximation to fitness optima in the new environment can occur by selection acting on standing genetic variation, modification of developmental patterns or phenotypic plasticity. Midas cichlids have recently colonized crater Lake Apoyo from great Lake Nicaragua. The photic environmen...

The NASA Discovery Deep Impact mission involves a unique experiment designed to excavate pristine materials from below the surface of comet. In July 2005, the Deep Impact (DI) spacecraft, will release a 360 kg probe that will collide with comet 9P/Tempel 1. This collision will excavate pristine materials from depth and produce a crater whose size and appearance will provide fundamental insights...

Introduction: The structure of the Chicxulub crater has been actively investigated by potential field modeling, seismic reflection and refraction surveys, and drilling during the decade since its recognition as the crater responsible for mass extinction which terminated the Cretaceous Period. Given the data sets that are now available to delineate crater structure a surprisingly diverse number ...

Introduction: The Lonar crater, India [1] is believed to have formed entirely on basaltic target rock (Deccan Trap, 65 Ma) and is therefore comparable to impact craters formed on other planetary surfaces with basaltic crusts. The genesis of Lonar crater has recently become complicated because isotopic studies on some impact-melt looking glasses found on the surface or in talus occurring mostly ...