[meteorite-list] 'Meteor' drop-tests, have been done?
From: Pekka Savolainen <pekka.savolainen_at_meteoritecentral.com>
Date: Thu Apr 22 10:22:39 2004 Message-ID: <3EECFA30.6090806_at_dlc.fi> --------------080809020602070805040903 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Hello, Bjorn and the list, we had some speculations last winter in Finland to try some kind of dropping, but as far as I know, nobody here has tried...;- We tried to find information about this kind of test, but with no results. We consulted people from different universities in Europe, US and Canada, and there was not information available in this kind of tests in practise. This far Bjurbole is the only known "trough-ice" case, and the weight of this beauty was 328 kg:s, so you really need a quite large and safe area, if you are going to get dropped pieces big enough to break the ice. Bjurbole made a hole 4,25 meters x 3,5 meters. Think this can be also quite simply calculated and simulated, but I´m not a mathematician... If you know the thickness and the structure of the ice, mass / size / angle of the falling specimen, this should not be a problem for a professional. It also should be remembered, if you make this kind of test somewhere, it´s only valid in exactly same circumstances. Usually the meteoroids don´t have any cosmic velocity left, when they drop, so they come down in free fall. The quite simple test is try to shoot a hole in the ice. Let´s say, you use 9.00 mm bullet and check the exact angle and the distance from the ice, when shoot, so the energy of the hit can be exactly calculated. More problematic case is the structure of the ice. If we are talking about steel-ice in the middle of the winter, let´s say, 60 cm:s thick, I bet, the hole you can get, it´s not deeper than 15 cm:s. The case is different in spring-time, when the ice with same 60 cm:s thickness is usually layered at least in 2 parts, strong steel-ice on the bottom, and week ice containing lot of water on the top. But anyway, think some modelling can be made. This may be a bit safer way than drop the stones from the plane. Anyway, if you are going to make this test, please, let me know the results, and also the dropping-area, so I know to wear a safety-helmet if happen to be near...;- take care, pekka Bjørn Sørheim wrote: >At 21:37 14.06.03 GMT, you wrote: > >>Hello List, >> >>For my part, living in a country with a tremendous number of >>ice-covered lakes in the winter time (a really LARGE area) dropping >>such objects on _ice lakes_ would be of even more interest. >> > >Just to avoid confusion: >I'm simply talking about a frozen, that is >a lake covered with ice - I bet you have seen it :-) > > >>Such a drop mark would surely have its very distinct kind of features, >>very different from other causes of marks. I have personally found no >>references to science on such features anywhere up to now... >> > >>Surely it must have been done, yes..? Any references? >> > >Best wishes, >Bjørn Sørheim > > > >______________________________________________ >Meteorite-list mailing list >Meteorite-list_at_meteoritecentral.com >http://www.pairlist.net/mailman/listinfo/meteorite-list > -- Pekka Savolainen Jokiharjuntie 4 FIN-71330 Rasala FINLAND + 358 400 818 912 Group Home Page: http://www.smartgroups.com/groups/eurocoin Group Email Address: eurocoin_at_smartgroups.com --------------080809020602070805040903 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <html> <head> </head> <body> <br> Hello, Bjorn and the list,<br> <br> we had some speculations last winter in Finland to try some <br> kind of dropping, but as far as I know, nobody here has tried...;-<br> <br> We tried to find information about this kind of test, but with <br> no results. We consulted people from different universities in<br> Europe, US and Canada, and there was not information available<br> in this kind of tests in practise.<br> <br> This far Bjurbole is the only known "trough-ice" case, and the<br> weight of this beauty was 328 kg:s, so you really need a quite<br> large and safe area, if you are going to get dropped pieces big<br> enough to break the ice. Bjurbole made a hole 4,25 meters x<br> 3,5 meters.<br> <br> Think this can be also quite simply calculated and simulated, <br> but I´m not a mathematician...<br> <br> If you know the thickness and the structure of the ice, mass /<br> size / angle of the falling specimen, this should not be a problem for a<br> professional. It also should be remembered, if you make this <br> kind of test somewhere, it´s only valid in exactly same circumstances.<br> <br> Usually the meteoroids don´t have any cosmic velocity left, when <br> they drop, so they come down in free fall. The quite simple test is<br> try to shoot a hole in the ice. Let´s say, you use 9.00 mm bullet and<br> check the exact angle and the distance from the ice, when shoot, so <br> the energy of the hit can be exactly calculated. More problematic case <br> is the structure of the ice. If we are talking about steel-ice in the middle <br> of the winter, let´s say, 60 cm:s thick, I bet, the hole you can get, it´s <br> not deeper than 15 cm:s. The case is different in spring-time, when the <br> ice with same 60 cm:s thickness is usually layered at least in 2 parts, <br> strong steel-ice on the bottom, and week ice containing lot of water on <br> the top. But anyway, think some modelling can be made. This may be<br> a bit safer way than drop the stones from the plane.<br> <br> Anyway, if you are going to make this test, please, let me know the results,<br> and also the dropping-area, so I know to wear a safety-helmet if happen to<br> be near...;-<br> <br> take care,<br> <br> pekka<br> <br> <br> <br> Bjørn Sørheim wrote:<br> <blockquote type="cite" cite="mid:200306151416.QAA24008_at_mail47.fg.online.no"> <pre wrap="">At 21:37 14.06.03 GMT, you wrote:<br></pre> <blockquote type="cite"> <pre wrap="">Hello List,<br><br>For my part, living in a country with a tremendous number of<br>ice-covered lakes in the winter time (a really LARGE area) dropping<br>such objects on _ice lakes_ would be of even more interest.<br></pre> </blockquote> <pre wrap=""><!----><br>Just to avoid confusion:<br>I'm simply talking about a frozen, that is<br>a lake covered with ice - I bet you have seen it :-)<br><br><br></pre> <blockquote type="cite"> <pre wrap="">Such a drop mark would surely have its very distinct kind of features,<br>very different from other causes of marks. I have personally found no<br>references to science on such features anywhere up to now... <br></pre> </blockquote> <pre wrap=""><!----><br></pre> <blockquote type="cite"> <pre wrap="">Surely it must have been done, yes..? Any references?<br></pre> </blockquote> <pre wrap=""><!----><br>Best wishes,<br>Bjørn Sørheim<br><br><br><br>______________________________________________<br>Meteorite-list mailing list<br><a class="moz-txt-link-abbreviated" href="mailto:Meteorite-list_at_meteoritecentral.com">Meteorite-list@meteoritecentral.com</a><br><a class="moz-txt-link-freetext" href="http://www.pairlist.net/mailman/listinfo/meteorite-list">http://www.pairlist.net/mailman/listinfo/meteorite-list</a><br><br></pre> </blockquote> <br> <pre class="moz-signature" cols="$mailwrapcol">-- Pekka Savolainen Jokiharjuntie 4 FIN-71330 Rasala FINLAND + 358 400 818 912 Group Home Page: <a class="moz-txt-link-freetext" href="http://www.smartgroups.com/groups/eurocoin">http://www.smartgroups.com/groups/eurocoin</a> Group Email Address: <a class="moz-txt-link-abbreviated" href="mailto:eurocoin_at_smartgroups.com">eurocoin@smartgroups.com</a> </pre> <br> </body> </html> --------------080809020602070805040903--Received on Sun 15 Jun 2003 06:58:56 PM PDT |
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