>>Thanks for your nice words. You carefully read the paper.
>>We made the sand flushy to destroy the force chains.
>>In this way hardly any energy is stored in the ground,
>>and the energy of the object is overwhelming. The
>>geophysics community calls this gravity driven. I just
>>talked about this at the Gordon conferences here in Colby,
>>Maine, USA and the geophysicists who were around
>>viewed it favorably.
>>Best regards, Detlef Lohse
Dear Meteorite-list,
I am forwarding the above friendly response from Dr. Lohse, the physicist from the Netherlands who designed the recent impact experiment and whose area of study is events of singularity. Apparently has just discussed the recent work modeling terrestrial impacts under discussion here at the physics' symposia "Gordon Conference" currently held in the US.
In his reply he emphasizes that the ratio of the impactor's energy to that of the potential energy in the ground makes the latter negligible. That's the case expected for the real asteroid impacting events. That suggests to me that it is the first time someone has actually modeled such an energy differential in the laboratory, helping to earn the work the honor of "first scalable impact event created in the laboratory", not to mention the differences they identified vs. videos relating to unique sedimentation and reverse jet they worked the physics out on which are different from liquid models that have been already investigated.
For example, it supports the idea that the meteorite winter that helped wipe out the dinosaurs was caused by terrestrial ejecta jetted in reverse along the entry trajectory, rather than from a splash, as most videos would indicate. That was done by an interesting, basically two dimensional cross experiment that I have never seen in a video. But then again you folks in the US are more privileged than much of the rest of the world when it comes to the media. The work also might also be useful to investigate under what impact conditions an earth meteoroid might theoretically be produced, which has previously been a topic of much interest to this group.
The goal of this work was clearly not to film any collision which will obviously help one get a handle on collisions in general, such as a drop falling on apuddle, and what happens on a small time scale; it was to reporduce for the first time the energy ratios contemplated for Earth's big extinction events. I hope the 599 other members of the meteorite list will join with me in wishing him congratulations and further encouragement to refine the results on sedimentation patterns and the resulting stress patterns in this interesting impact research, and thanks to Ron Baalke at JPL for the initial post alerting us to this. The list is described at http://www.meteoritecentral.com and has members who are interested in all aspects of meteorites, impacts, for the scientific, hobby and resulting commerce of meteorite trade.
Saludos,
Doug Dawn
N. 25.4° W. 100.2°
Mexico
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