Re: [meteorite-list] 1 in 3200 odds of human impact (help)
Thanks Kirk. I was more complaining about the ridiculous precision of the odds they give and not meaning to suggest mine was a better order of magnitude, but only that people read this sort of precision and naturally assume there is some supercomputer and infallible black box behind it if they start quoting things like 1:3200, when the reality of the situation is that someone else could defend their same calculation and have it ten or even a hundred times less in this example. Also those such probabilities are calculated on limited information. Just look what happened: NASA: 1:3200 and coming down Friday evening. Oops! Changed orientation, our probability is bullhonkey (yet the media continues to quote it), every assumption is changed. The probability is now 1:1,235.141592 It's not an academic exercise; on the met-list it's of general interest for those interested in meteorites striking people, houses and even the occasional loveable crater-headed dog. But very seriously a risk assessment needs to be done when making such decisions as converting used satellites into projectiles although no one will agree on a universal level of risk that is OK, the first step is to estimate the probability. In the future it will be inevitable that this haphazard, seat of the pants crashing, doesn't continue as earth adds hundreds of satellites each year and we already have 5000 - 6000 up there plus about triple that amount of debris, if I haven't guessed right. Satellites will need not only to make it up, but to have a safe plan to decommission them, like the evolution of safety controls in the auto industry. It has to happen, though it's going to be a huge mess to sort out agreements and give credits to poorer nations that haven't created the current mess and are cash-strapped and then develop their satellite networks. The risk assessment of a 1:10,000 of a minor asteroid hitting earth causes all this commotion... imagine the zoo all this satellite mess is headed to turn into. Hopefully we can figure out how to economically remove satellites safely, or better yet create a cottage industry of salvage entrepreneurs that can make a go at it and can be paid to remove scrap as well by the offending parties... So, when NASA says 1:3200 - it just looks darn foolish and a bit arrogant, too if not given with further explanation. It's not like this is a minor detail for scientists. It is everyone's right to know and no government's right to put innocents at higher risk, although they do it all the time... Kindest wishes Doug -Original Message- From: Becky and Kirk ba...@chorus.net To: Meteorite-list Meteorite-list@meteoritecentral.com; MexicoDoug mexicod...@aim.com Sent: Sun, Sep 25, 2011 12:47 am Subject: Re: [meteorite-list] 1 in 3200 odds of human impact (help) WOW---some pretty good calculations and science there DougBRAVO!! NASA screws up yet again!! Kirk.:-) - Original Message - From: MexicoDoug mexicod...@aim.com To: Meteorite-list@meteoritecentral.com Sent: Saturday, September 24, 2011 11:31 PM Subject: [meteorite-list] 1 in 3200 odds of human impact (help) Hi listers I'm very suspicious of this widely quoted 1 in 3200 that is being passed off as a scientific number by NASA. Not 1:3000, nor between 1:1000 to 1:10,000: but 1:3200. This foolishly precise assertation, which if you've read The Little Prince you immediately suspect it is overstated due to the author's calculations 70 years ago there...where a similar calculation is actually done ... Average cross sectional area of a person? (Depends if it is in the morning when everyone is praying, I guess, or in the afternoon when everyone is running out of work)...let's say: Cross section per person:18 inches by 18 inches (1.5 x 1.5 sq. feet) World population: 6.964 X 10^9 living souls World Area: 196,939,900 sq miles Calculations: * Cross section per person = 2.5 sq. feet * current world population occupies 624.3 square miles (a wee bit bigger than Guam, and smaller than Singapore) * people that could fit on Earth's surface: 2,196,000,000,000,000 (2.2 million X 10^9) * Fraction of Earth's surface that's people = 6.96 / (2,196,000) = 0.0317 = People occupy *ONLY* 3.2 parts per million (3.2 ppm) of the earth's surface So, saving rounding till the end, each piece of UARS actually has a 1/315,457 chance of falling on people (1/0.0317). In rounded numbers, that's about 1:320,000 per fragment == 26 fragments approximately 1:12,000 chance. I guess if you are American you need more space than if you are Indonesian, and changing it to a 18 inches X 17 inches would change the result by 6% ie, if 3200 were right for 18X18 it would now be about 1:3000, and that is one of so many assumptions making the 3200 number a total joke of fake scientific confidence. If you gave everyone a square yard ((91.4 cm)^2) instead, it would be in the 3000
Re: [meteorite-list] 1 in 3200 odds of human impact (help)
Dear Doug, List, The effective cross section of a human varies widely with the path of the debris, its angle relative to the Earth's surface.. It's only 2.5 sq. ft. if the debris is falling vertically. If it's moving at a shallow angle to the horizon, the human target is 5-6 feet high and 2 ft. wide or about 10 sq. ft. at very shallow angles, 7 sq. ft. at 45 degrees, etc. As far as stacking people up, you can only stack them up on land, not by using the entire surface of the planet. (Sea stacking sucks, er, sinks.) The total land area of the Earth is 1,603,176,817,500,000 square feet. Give everybody four square feet, and you only have room for 400 trillion friendly folks. Or with a 2.5 sq. ft. cross section, 642 trillion friendly folks. (With so little space apiece, they have to be friendly...) Using the 4 sq. ft. allowance and a mere 6 billion people, only one in 66,667 people patches is occupied, so the odds of a person patch being the occupied one is 66,666-to-1. Using an 8 sq. ft. patch, gives a result close to 32,000-to-1, ten times the NASA estimate and 1/10th your estimate. Actual statistics is something else. What are the sizes of the debris? Only if the debris is much smaller than the people-patch-size are the odds so calculated valid. If the debris is much larger than one or two people patches, you need to know the likelihood of people clustering together. What if you set out one person every 66,666 patches and they all walk in to the center of the general area to chat with each other? Humans cluster strongly -- cities are the result. There was, it happens, a lot more Siberia for the Tunguska Object to hit than there were Londons. Things falling in Mexico City (the most populous on Earth) have a greater chance of hitting people than things falling in say, Montana, but there's a lot more of Montana. We need to include a clustering coefficient in the calculation. Fortunately, I'm not up to it... Sterling K. Webb - Original Message - From: MexicoDoug mexicod...@aim.com To: Meteorite-list@meteoritecentral.com Sent: Saturday, September 24, 2011 11:31 PM Subject: [meteorite-list] 1 in 3200 odds of human impact (help) Hi listers I'm very suspicious of this widely quoted 1 in 3200 that is being passed off as a scientific number by NASA. Not 1:3000, nor between 1:1000 to 1:10,000: but 1:3200. This foolishly precise assertation, which if you've read The Little Prince you immediately suspect it is overstated due to the author's calculations 70 years ago there...where a similar calculation is actually done ... Average cross sectional area of a person? (Depends if it is in the morning when everyone is praying, I guess, or in the afternoon when everyone is running out of work)...let's say: Cross section per person:18 inches by 18 inches (1.5 x 1.5 sq. feet) World population: 6.964 X 10^9 living souls World Area: 196,939,900 sq miles Calculations: * Cross section per person = 2.5 sq. feet * current world population occupies 624.3 square miles (a wee bit bigger than Guam, and smaller than Singapore) * people that could fit on Earth's surface: 2,196,000,000,000,000 (2.2 million X 10^9) * Fraction of Earth's surface that's people = 6.96 / (2,196,000) = 0.0317 = People occupy *ONLY* 3.2 parts per million (3.2 ppm) of the earth's surface So, saving rounding till the end, each piece of UARS actually has a 1/315,457 chance of falling on people (1/0.0317). In rounded numbers, that's about 1:320,000 per fragment == 26 fragments approximately 1:12,000 chance. I guess if you are American you need more space than if you are Indonesian, and changing it to a 18 inches X 17 inches would change the result by 6% ie, if 3200 were right for 18X18 it would now be about 1:3000, and that is one of so many assumptions making the 3200 number a total joke of fake scientific confidence. If you gave everyone a square yard ((91.4 cm)^2) instead, it would be in the 3000 range. But here are the defficiencies I think of looking at it this way: * this looks at the whole world vs. the limited satellite trace. A true measurement would do a little calculus along the path considering the population density and the probability of earlier or later entry which could change probabilities by an order of magnitude easily. * I think what I did would work for 26 darts, but not hunks of significant size compared to a person's area unit. * Finally there is the Sylacauga effect for bouncing material that will affect things another factor of 2, 3, 4 who knows... There must be a half dozen other complicating factors to do this right. Does anyone know what has been considered to arrive at the bogusly precise 3200-1 odds being fed to us? Love to hear any improvements on the above model (if you can call it a model) which I got the 1:12,000 as a streaming (unverified) starting point ...
Re: [meteorite-list] 1 in 3200 odds of human impact (help)
...and of course, my calculation only applies to the one-in-three falls over land, not the two-in-three over water. Dilute one part of the calculation with two parts of water... What you're talking about --- that specious popular precision --- is the result of achieving high precision and low accuracy at the same time. This is what most newspaper and press releases statistics achieve. http://en.wikipedia.org/wiki/Accuracy_and_precision Sterling K. Webb - - Original Message - From: MexicoDoug mexicod...@aim.com To: ba...@chorus.net; Meteorite-list@meteoritecentral.com Sent: Sunday, September 25, 2011 1:27 AM Subject: Re: [meteorite-list] 1 in 3200 odds of human impact (help) Thanks Kirk. I was more complaining about the ridiculous precision of the odds they give and not meaning to suggest mine was a better order of magnitude, but only that people read this sort of precision and naturally assume there is some supercomputer and infallible black box behind it if they start quoting things like 1:3200, when the reality of the situation is that someone else could defend their same calculation and have it ten or even a hundred times less in this example. Also those such probabilities are calculated on limited information. Just look what happened: NASA: 1:3200 and coming down Friday evening. Oops! Changed orientation, our probability is bullhonkey (yet the media continues to quote it), every assumption is changed. The probability is now 1:1,235.141592 It's not an academic exercise; on the met-list it's of general interest for those interested in meteorites striking people, houses and even the occasional loveable crater-headed dog. But very seriously a risk assessment needs to be done when making such decisions as converting used satellites into projectiles although no one will agree on a universal level of risk that is OK, the first step is to estimate the probability. In the future it will be inevitable that this haphazard, seat of the pants crashing, doesn't continue as earth adds hundreds of satellites each year and we already have 5000 - 6000 up there plus about triple that amount of debris, if I haven't guessed right. Satellites will need not only to make it up, but to have a safe plan to decommission them, like the evolution of safety controls in the auto industry. It has to happen, though it's going to be a huge mess to sort out agreements and give credits to poorer nations that haven't created the current mess and are cash-strapped and then develop their satellite networks. The risk assessment of a 1:10,000 of a minor asteroid hitting earth causes all this commotion... imagine the zoo all this satellite mess is headed to turn into. Hopefully we can figure out how to economically remove satellites safely, or better yet create a cottage industry of salvage entrepreneurs that can make a go at it and can be paid to remove scrap as well by the offending parties... So, when NASA says 1:3200 - it just looks darn foolish and a bit arrogant, too if not given with further explanation. It's not like this is a minor detail for scientists. It is everyone's right to know and no government's right to put innocents at higher risk, although they do it all the time... Kindest wishes Doug -Original Message- From: Becky and Kirk ba...@chorus.net To: Meteorite-list Meteorite-list@meteoritecentral.com; MexicoDoug mexicod...@aim.com Sent: Sun, Sep 25, 2011 12:47 am Subject: Re: [meteorite-list] 1 in 3200 odds of human impact (help) WOW---some pretty good calculations and science there DougBRAVO!! NASA screws up yet again!! Kirk.:-) - Original Message - From: MexicoDoug mexicod...@aim.com To: Meteorite-list@meteoritecentral.com Sent: Saturday, September 24, 2011 11:31 PM Subject: [meteorite-list] 1 in 3200 odds of human impact (help) Hi listers I'm very suspicious of this widely quoted 1 in 3200 that is being passed off as a scientific number by NASA. Not 1:3000, nor between 1:1000 to 1:10,000: but 1:3200. This foolishly precise assertation, which if you've read The Little Prince you immediately suspect it is overstated due to the author's calculations 70 years ago there...where a similar calculation is actually done ... Average cross sectional area of a person? (Depends if it is in the morning when everyone is praying, I guess, or in the afternoon when everyone is running out of work)...let's say: Cross section per person:18 inches by 18 inches (1.5 x 1.5 sq. feet) World population: 6.964 X 10^9 living souls World Area: 196,939,900 sq miles Calculations: * Cross section per person = 2.5 sq. feet * current world population occupies 624.3 square miles (a wee bit bigger than Guam, and smaller than Singapore) * people that could fit on Earth's surface: 2,196,000,000,000,000 (2.2 million X 10^9) * Fraction of Earth's surface that's
Re: [meteorite-list] 1 in 3200 odds of human impact (help)
Maybe they were calculating odds in the US only at the 1:3200. Stuart McDaniel Lawndale, NC Secr., Cleve. Co. Astronomical Society IMCA #9052 Member - KCA, KBCA, CDUSA -Original Message- From: MexicoDoug Sent: Sunday, September 25, 2011 12:31 AM To: Meteorite-list@meteoritecentral.com Subject: [meteorite-list] 1 in 3200 odds of human impact (help) Hi listers I'm very suspicious of this widely quoted 1 in 3200 that is being passed off as a scientific number by NASA. Not 1:3000, nor between 1:1000 to 1:10,000: but 1:3200. This foolishly precise assertation, which if you've read The Little Prince you immediately suspect it is overstated due to the author's calculations 70 years ago there...where a similar calculation is actually done ... Average cross sectional area of a person? (Depends if it is in the morning when everyone is praying, I guess, or in the afternoon when everyone is running out of work)...let's say: Cross section per person:18 inches by 18 inches (1.5 x 1.5 sq. feet) World population: 6.964 X 10^9 living souls World Area: 196,939,900 sq miles Calculations: * Cross section per person = 2.5 sq. feet * current world population occupies 624.3 square miles (a wee bit bigger than Guam, and smaller than Singapore) * people that could fit on Earth's surface: 2,196,000,000,000,000 (2.2 million X 10^9) * Fraction of Earth's surface that's people = 6.96 / (2,196,000) = 0.0317 = People occupy *ONLY* 3.2 parts per million (3.2 ppm) of the earth's surface So, saving rounding till the end, each piece of UARS actually has a 1/315,457 chance of falling on people (1/0.0317). In rounded numbers, that's about 1:320,000 per fragment == 26 fragments approximately 1:12,000 chance. I guess if you are American you need more space than if you are Indonesian, and changing it to a 18 inches X 17 inches would change the result by 6% ie, if 3200 were right for 18X18 it would now be about 1:3000, and that is one of so many assumptions making the 3200 number a total joke of fake scientific confidence. If you gave everyone a square yard ((91.4 cm)^2) instead, it would be in the 3000 range. But here are the defficiencies I think of looking at it this way: * this looks at the whole world vs. the limited satellite trace. A true measurement would do a little calculus along the path considering the population density and the probability of earlier or later entry which could change probabilities by an order of magnitude easily. * I think what I did would work for 26 darts, but not hunks of significant size compared to a person's area unit. * Finally there is the Sylacauga effect for bouncing material that will affect things another factor of 2, 3, 4 who knows... There must be a half dozen other complicating factors to do this right. Does anyone know what has been considered to arrive at the bogusly precise 3200-1 odds being fed to us? Love to hear any improvements on the above model (if you can call it a model) which I got the 1:12,000 as a streaming (unverified) starting point ... Kindest wishes Doug __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] 1 in 3200 odds of human impact (help)
Hi Stuart, List, Sterling, Kirk and all, The official statement based on a 9-year old estimate which was magically updated: Estimated human casualty risk (updated to 2011): ~ 1 in 3200 which I interpret to mean death or injury, though it could be interpreted as death alone. NASA/DoD used FPBBNOQ, their version of the risk assessment program to determine this, (a.k.a. falsely precise black box that no one questions otherwise known as ORSAT) NASA's ORSAT calculations were that the impact: * Cross sectional area 3.49 m^2 of UARS debris (that's 37.5 square feet) * 26 pieces surviving * 532.38 kg mass total impacting weight ORSAT, their proverbial magic black box: Estimated human casualty risk (updated to 2011): ~ 1 in 3200 The excuses and justifications and sweet talk (something like we hear in politics or by the slouchers that promise results at work IMO): No NASA or USG human casualty reentry risk limits existed when UARS was designed, built, and launched. • NASA, the USG, and some foreign space agencies now seek to limit human casualty risks from reentering space objects to less than 1 in 10,000. • UARS is a moderate-sized space object. Uncontrolled reentries of objects more massive than UARS are not frequent, but neither are they unusual. – Combined Dragon mockup and Falcon 9 second stage reentry in June 2010 was more massive. • Since the beginning of the space age, there has been no confirmed report of an injury resulting from reentering space objects. Read all about it here: ref: http://www.nasa.gov/pdf/585584main_UARS_Status.pdf Kindest wishes Doug -Original Message- From: Stuart McDaniel actionshoot...@carolina.rr.com To: Meteorite-list Meteorite-list@meteoritecentral.com; MexicoDoug mexicod...@aim.com Sent: Sun, Sep 25, 2011 3:38 pm Subject: Re: [meteorite-list] 1 in 3200 odds of human impact (help) Maybe they were calculating odds in the US only at the 1:3200. Stuart McDaniel Lawndale, NC Secr., Cleve. Co. Astronomical Society IMCA #9052 Member - KCA, KBCA, CDUSA -Original Message- From: MexicoDoug Sent: Sunday, September 25, 2011 12:31 AM To: Meteorite-list@meteoritecentral.com Subject: [meteorite-list] 1 in 3200 odds of human impact (help) Hi listers I'm very suspicious of this widely quoted 1 in 3200 that is being passed off as a scientific number by NASA. Not 1:3000, nor between 1:1000 to 1:10,000: but 1:3200. This foolishly precise assertation, which if you've read The Little Prince you immediately suspect it is overstated due to the author's calculations 70 years ago there...where a similar calculation is actually done ... Average cross sectional area of a person? (Depends if it is in the morning when everyone is praying, I guess, or in the afternoon when everyone is running out of work)...let's say: Cross section per person:18 inches by 18 inches (1.5 x 1.5 sq. feet) World population: 6.964 X 10^9 living souls World Area: 196,939,900 sq miles Calculations: * Cross section per person = 2.5 sq. feet * current world population occupies 624.3 square miles (a wee bit bigger than Guam, and smaller than Singapore) * people that could fit on Earth's surface: 2,196,000,000,000,000 (2.2 million X 10^9) * Fraction of Earth's surface that's people = 6.96 / (2,196,000) = 0.0317 = People occupy *ONLY* 3.2 parts per million (3.2 ppm) of the earth's surface So, saving rounding till the end, each piece of UARS actually has a 1/315,457 chance of falling on people (1/0.0317). In rounded numbers, that's about 1:320,000 per fragment == 26 fragments approximately 1:12,000 chance. I guess if you are American you need more space than if you are Indonesian, and changing it to a 18 inches X 17 inches would change the result by 6% ie, if 3200 were right for 18X18 it would now be about 1:3000, and that is one of so many assumptions making the 3200 number a total joke of fake scientific confidence. If you gave everyone a square yard ((91.4 cm)^2) instead, it would be in the 3000 range. But here are the defficiencies I think of looking at it this way: * this looks at the whole world vs. the limited satellite trace. A true measurement would do a little calculus along the path considering the population density and the probability of earlier or later entry which could change probabilities by an order of magnitude easily. * I think what I did would work for 26 darts, but not hunks of significant size compared to a person's area unit. * Finally there is the Sylacauga effect for bouncing material that will affect things another factor of 2, 3, 4 who knows... There must be a half dozen other complicating factors to do this right. Does anyone know what has been considered to arrive at the bogusly precise 3200-1 odds being fed to us? Love to hear any improvements on the above model (if you can call it a model) which I got the 1:12,000 as a streaming (unverified) starting point ... Kindest wishes Doug
Re: [meteorite-list] 1 in 3200 odds of human impact (help)
G'Day Doug and list Lets not forget SkyLab What all that means, contend NASA'S statisticians, is that the chance of any remnant striking a human being is only 1 in 152; the probability of any specific person being struck is 1 in 600 billion-far less than the chance of being hit by a bolt of lightning or winning a lottery. http://www.time.com/time/magazine/article/0,9171,920502,00.html Andre's husband Mervin -- president of the local town council at the time -- issued the Yanks a ticket for littering. It remains unpaid, 21 years later. http://www.wired.com/science/discoveries/news/2001/03/42564?currentPage= all Cheers John Cabassi -Original Message- From: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] On Behalf Of MexicoDoug Sent: Sunday, September 25, 2011 1:32 PM To: actionshoot...@carolina.rr.com; Meteorite-list@meteoritecentral.com Subject: Re: [meteorite-list] 1 in 3200 odds of human impact (help) Hi Stuart, List, Sterling, Kirk and all, The official statement based on a 9-year old estimate which was magically updated: Estimated human casualty risk (updated to 2011): ~ 1 in 3200 which I interpret to mean death or injury, though it could be interpreted as death alone. NASA/DoD used FPBBNOQ, their version of the risk assessment program to determine this, (a.k.a. falsely precise black box that no one questions otherwise known as ORSAT) NASA's ORSAT calculations were that the impact: * Cross sectional area 3.49 m^2 of UARS debris (that's 37.5 square feet) * 26 pieces surviving * 532.38 kg mass total impacting weight ORSAT, their proverbial magic black box: Estimated human casualty risk (updated to 2011): ~ 1 in 3200 The excuses and justifications and sweet talk (something like we hear in politics or by the slouchers that promise results at work IMO): No NASA or USG human casualty reentry risk limits existed when UARS was designed, built, and launched. . NASA, the USG, and some foreign space agencies now seek to limit human casualty risks from reentering space objects to less than 1 in 10,000. . UARS is a moderate-sized space object. Uncontrolled reentries of objects more massive than UARS are not frequent, but neither are they unusual. - Combined Dragon mockup and Falcon 9 second stage reentry in June 2010 was more massive. . Since the beginning of the space age, there has been no confirmed report of an injury resulting from reentering space objects. Read all about it here: ref: http://www.nasa.gov/pdf/585584main_UARS_Status.pdf Kindest wishes Doug -Original Message- From: Stuart McDaniel actionshoot...@carolina.rr.com To: Meteorite-list Meteorite-list@meteoritecentral.com; MexicoDoug mexicod...@aim.com Sent: Sun, Sep 25, 2011 3:38 pm Subject: Re: [meteorite-list] 1 in 3200 odds of human impact (help) Maybe they were calculating odds in the US only at the 1:3200. Stuart McDaniel Lawndale, NC Secr., Cleve. Co. Astronomical Society IMCA #9052 Member - KCA, KBCA, CDUSA -Original Message- From: MexicoDoug Sent: Sunday, September 25, 2011 12:31 AM To: Meteorite-list@meteoritecentral.com Subject: [meteorite-list] 1 in 3200 odds of human impact (help) Hi listers I'm very suspicious of this widely quoted 1 in 3200 that is being passed off as a scientific number by NASA. Not 1:3000, nor between 1:1000 to 1:10,000: but 1:3200. This foolishly precise assertation, which if you've read The Little Prince you immediately suspect it is overstated due to the author's calculations 70 years ago there...where a similar calculation is actually done ... Average cross sectional area of a person? (Depends if it is in the morning when everyone is praying, I guess, or in the afternoon when everyone is running out of work)...let's say: Cross section per person:18 inches by 18 inches (1.5 x 1.5 sq. feet) World population: 6.964 X 10^9 living souls World Area: 196,939,900 sq miles Calculations: * Cross section per person = 2.5 sq. feet * current world population occupies 624.3 square miles (a wee bit bigger than Guam, and smaller than Singapore) * people that could fit on Earth's surface: 2,196,000,000,000,000 (2.2 million X 10^9) * Fraction of Earth's surface that's people = 6.96 / (2,196,000) = 0.0317 = People occupy *ONLY* 3.2 parts per million (3.2 ppm) of the earth's surface So, saving rounding till the end, each piece of UARS actually has a 1/315,457 chance of falling on people (1/0.0317). In rounded numbers, that's about 1:320,000 per fragment == 26 fragments approximately 1:12,000 chance. I guess if you are American you need more space than if you are Indonesian, and changing it to a 18 inches X 17 inches would change the result by 6% ie, if 3200 were right for 18X18 it would now be about 1:3000, and that is one of so many assumptions making the 3200 number a total joke of fake scientific confidence. If you gave everyone a square yard ((91.4 cm)^2) instead, it would be in the 3000
Re: [meteorite-list] 1 in 3200 odds of human impact (help)
WOW---some pretty good calculations and science there DougBRAVO!! NASA screws up yet again!! Kirk.:-) - Original Message - From: MexicoDoug mexicod...@aim.com To: Meteorite-list@meteoritecentral.com Sent: Saturday, September 24, 2011 11:31 PM Subject: [meteorite-list] 1 in 3200 odds of human impact (help) Hi listers I'm very suspicious of this widely quoted 1 in 3200 that is being passed off as a scientific number by NASA. Not 1:3000, nor between 1:1000 to 1:10,000: but 1:3200. This foolishly precise assertation, which if you've read The Little Prince you immediately suspect it is overstated due to the author's calculations 70 years ago there...where a similar calculation is actually done ... Average cross sectional area of a person? (Depends if it is in the morning when everyone is praying, I guess, or in the afternoon when everyone is running out of work)...let's say: Cross section per person:18 inches by 18 inches (1.5 x 1.5 sq. feet) World population: 6.964 X 10^9 living souls World Area: 196,939,900 sq miles Calculations: * Cross section per person = 2.5 sq. feet * current world population occupies 624.3 square miles (a wee bit bigger than Guam, and smaller than Singapore) * people that could fit on Earth's surface: 2,196,000,000,000,000 (2.2 million X 10^9) * Fraction of Earth's surface that's people = 6.96 / (2,196,000) = 0.0317 = People occupy *ONLY* 3.2 parts per million (3.2 ppm) of the earth's surface So, saving rounding till the end, each piece of UARS actually has a 1/315,457 chance of falling on people (1/0.0317). In rounded numbers, that's about 1:320,000 per fragment == 26 fragments approximately 1:12,000 chance. I guess if you are American you need more space than if you are Indonesian, and changing it to a 18 inches X 17 inches would change the result by 6% ie, if 3200 were right for 18X18 it would now be about 1:3000, and that is one of so many assumptions making the 3200 number a total joke of fake scientific confidence. If you gave everyone a square yard ((91.4 cm)^2) instead, it would be in the 3000 range. But here are the defficiencies I think of looking at it this way: * this looks at the whole world vs. the limited satellite trace. A true measurement would do a little calculus along the path considering the population density and the probability of earlier or later entry which could change probabilities by an order of magnitude easily. * I think what I did would work for 26 darts, but not hunks of significant size compared to a person's area unit. * Finally there is the Sylacauga effect for bouncing material that will affect things another factor of 2, 3, 4 who knows... There must be a half dozen other complicating factors to do this right. Does anyone know what has been considered to arrive at the bogusly precise 3200-1 odds being fed to us? Love to hear any improvements on the above model (if you can call it a model) which I got the 1:12,000 as a streaming (unverified) starting point ... Kindest wishes Doug __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
