Editing Talk:2027: Lightning Distance
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:* ''n'' for air at 0 C, 1 atm, is closer to 1.000292, according to both {{w|List_of_refractive_indices|the Wikipedia link}} and also the "Simple Shop-floor Formula" given by NIST at [https://emtoolbox.nist.gov/wavelength/documentation.asp the bottom of this site]. This would give a <math>{\Delta n}</math> of 0.000023, and a time-to-distance conversion value of <math>\frac{c}{\Delta n} \approx 7.9\cdot10^9</math> mi/s. | :* ''n'' for air at 0 C, 1 atm, is closer to 1.000292, according to both {{w|List_of_refractive_indices|the Wikipedia link}} and also the "Simple Shop-floor Formula" given by NIST at [https://emtoolbox.nist.gov/wavelength/documentation.asp the bottom of this site]. This would give a <math>{\Delta n}</math> of 0.000023, and a time-to-distance conversion value of <math>\frac{c}{\Delta n} \approx 7.9\cdot10^9</math> mi/s. | ||
:* Thunderstorms rarely occur at 0 C. Using values for 30 C (86 F) instead, we have 1.000261 for air (from the simple NIST formula) and 1.000429 for radio waves (from Table 1, p. 8 of [https://www.fig.net/resources/proceedings/fig_proceedings/fig_2002/Js28/JS28_rueger.pdf the Rueger paper]). This gives a <math>{\Delta n}</math> of 0.000168, and a time-to-distance conversion value of <math>\frac{c}{\Delta n} \approx 1.1\cdot10^9</math> mi/s. | :* Thunderstorms rarely occur at 0 C. Using values for 30 C (86 F) instead, we have 1.000261 for air (from the simple NIST formula) and 1.000429 for radio waves (from Table 1, p. 8 of [https://www.fig.net/resources/proceedings/fig_proceedings/fig_2002/Js28/JS28_rueger.pdf the Rueger paper]). This gives a <math>{\Delta n}</math> of 0.000168, and a time-to-distance conversion value of <math>\frac{c}{\Delta n} \approx 1.1\cdot10^9</math> mi/s. | ||
− | :This suggests that the conversion value is the desired 5 billion for ''some'' temperature between 0 and 30 C. Linear interpolation of the above suggests this temperature is about 13 C or 55 F | + | :This suggests that the conversion value is the desired 5 billion for ''some'' temperature between 0 and 30 C. Linear interpolation of the above suggests this temperature is about 13 C or 55 F. More to the point, the conversion value varies too strongly with temperature for there to be a simple rule. That being said, I do like that the 5 billion figure ties in nicely with the familiar (in USA) ''divide by 5'' rule. [[User:Redbelly98|Redbelly98]] ([[User talk:Redbelly98|talk]]) 02:18, 6 August 2018 (UTC) |
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'''Assumptions on the medium properties sound?''' | '''Assumptions on the medium properties sound?''' |