[math-fun] Interplanetary microbes?
Whether the Tunguska object was made mainly of rock, ice, dry ice, frozen mud, or whatever is essentially irrelevant to my questions. Who cares? Either way the temperatures involved at the surface are far larger than the vaporization point and ditto the total energies... The only way in which the composition is relevant is the materials strength and toughness issue. I happen to think a 1000 ton body COULD be ejected from earth in 1 piece if it were made of some very tough stuff like solid steel coated with ablative heat shielding --I think that could survive the initial blast without fragmenting. But 1000 ton chunks of steel are not available naturally on Earth. Whether typical rocks, permafrost, etc could survive it without fragmenting, is the question. They often have low tensile strength and are brittle. I can easily break even tough rocks using only my bare hands to provide the power, and with the aid of huge explosive blasts and for much larger rocks, it should be a lot easier than with my hands and a small rock... The larger the rock, the harder it is to keep it in 1 piece, because the stresses at a given acceleration grow with the size. That is why microbes (small) have no difficulty surviving huge accelerations even though from the materials point of view they are weak. But it is very hard for large objects to survive high accelerations. For example, a microbe easily survives inside a rifle bullet hitting a sandbag, 10^5 to 10^6 g. A human (much larger) usually dies if subjected to a mere 50g. I claim (without evidence) an elephant would usually die if subjected to a mere 10g. Beached whales die (slowly) with only 1g and large whales should die quickly at 3g. Andrei Yu. Ol'khovatov's "tectonic" "explanation" of Tunguska: http://olkhov.narod.ru/tunguska/tunguska.htm sounds to me like utter garbage for a vast number of obvious reasons. The wikipedia page's evidence clearly proves it was large and extraterrestrial and airburst (and it was not an "antimatter bullet" or mini black hole either).
What about multiple roughly simultaneous impacts? If the two debris clouds interact violently enough, then there may be lots of collisions at altitude. Big thing smacks smaller thing(s), momentum transfer, and -bonk- out into space goes something that would never make it on its own. None of the colliding bodies would even have to achieve groundside escape velocity. -----Original Message----- From: math-fun-bounces@mailman.xmission.com [mailto:math-fun-bounces@mailman.xmission.com] On Behalf Of Warren Smith Sent: Friday, April 13, 2012 8:42 AM To: math-fun@mailman.xmission.com Subject: [EXTERNAL] [math-fun] Interplanetary microbes? Whether the Tunguska object was made mainly of rock, ice, dry ice, frozen mud, or whatever is essentially irrelevant to my questions. Who cares? Either way the temperatures involved at the surface are far larger than the vaporization point and ditto the total energies... The only way in which the composition is relevant is the materials strength and toughness issue. I happen to think a 1000 ton body COULD be ejected from earth in 1 piece if it were made of some very tough stuff like solid steel coated with ablative heat shielding --I think that could survive the initial blast without fragmenting. But 1000 ton chunks of steel are not available naturally on Earth. Whether typical rocks, permafrost, etc could survive it without fragmenting, is the question. They often have low tensile strength and are brittle. I can easily break even tough rocks using only my bare hands to provide the power, and with the aid of huge explosive blasts and for much larger rocks, it should be a lot easier than with my hands and a small rock... The larger the rock, the harder it is to keep it in 1 piece, because the stresses at a given acceleration grow with the size. That is why microbes (small) have no difficulty surviving huge accelerations even though from the materials point of view they are weak. But it is very hard for large objects to survive high accelerations. For example, a microbe easily survives inside a rifle bullet hitting a sandbag, 10^5 to 10^6 g. A human (much larger) usually dies if subjected to a mere 50g. I claim (without evidence) an elephant would usually die if subjected to a mere 10g. Beached whales die (slowly) with only 1g and large whales should die quickly at 3g. Andrei Yu. Ol'khovatov's "tectonic" "explanation" of Tunguska: http://olkhov.narod.ru/tunguska/tunguska.htm sounds to me like utter garbage for a vast number of obvious reasons. The wikipedia page's evidence clearly proves it was large and extraterrestrial and airburst (and it was not an "antimatter bullet" or mini black hole either). _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
participants (2)
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Torgerson, Mark D -
Warren Smith