In reply to Horace Heffner's message of Sat, 20 Aug 2011 11:32:03 -0800: Hi, [snip] >Using a mean earth diameter of 6371 km, a mean albedo of 0.3, and >solar insolation of 1 W/m^2, we have a reflected power of:
Solar insolation is around 1 kW (not 1 W) / m^2. > > P = (6.371x10^6 m)^2 * Pi * 0.3 * (1 W/m^2) = 3.8x10^13 W > >HAARP type transmitters around the world radiate at an order of a GW, >or 10^9 W, but are directional and intermittent. The narrow >bandwidth helps compensate for the 4 orders of magnitude difference, >however. > >We currently have the ability to find extrasolar planets, and look at >their spectra and temperatures, so we should expect more advanced >civilizations to have similar capabilities and programs to monitor >nearby worlds, especially those having liquid water. > >All this is food for thought ... > >Best regards, > >Horace Heffner >http://www.mtaonline.net/~hheffner/ > > > Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
