Ancient Mars impacts created tornado-like winds that scoured surfaceKEVINAMBROSE 7 hours ago
http://keoler.com/ancient-mars-impacts-created-tornado-like-winds-that-scoured-surface
Brown University geologist Peter Schultz observed sets of strange bright streaks coming from a few large-impact craters on the planet’s surface. The streaks are strange because they extend much farther from the craters than normal ejecta patterns, and they are only visible in thermal infrared images taken during the Martian night. Using geological observation, laboratory impact experiments and computer modeling, Schultz and Brown graduate student Stephanie Quintana have offered a new explanation for how those streaks were formed. They show that tornado-like wind vortices created by crater-forming impacts and swirling at 500 miles per hour or more, scoured the surface and blasted away dust and small rocks to expose the blockier surfaces beneath.
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The researchers’ experiments show that the presence of volatile compounds, a thick layer of water ice on the surface or subsurface, affect the vapor amount that rushes out from an impact. The streaks now can serve as indicators of whether ice may have been present at the time of an impact, which could lend insight into reconstructions of past climate on Mars. Equally possible, the streaks could be related to the composition of the impactor, such as rare collisions by high-volatile objects, such as comets.
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The paper referenced:
http://www.sciencedirect.com/science/article/pii/S0019103516305942
