From: Michael Tarbell <mtarbell.nul> Date: Fri, 24 Aug 2012 13:39:53 -0600 Archived: Sat, 25 Aug 2012 05:34:26 -0400 Subject: Re: Chasing Mexican UFOs >From: Bruce Maccabee<brumac.nul> >To: post.nul >Date: Tue, 21 Aug 2012 21:59:34 -0400 (EDT) >Subject: Re: Chasing Mexican UFOs <snip> >As my article shows, the FLIR system was pointed toward the area >of the oil field, about 100 miles away, as the plane flew >eastward for many miles. I denonstrated reasonably good, >although not perfect, agreement between the FLIR lights and the >oil burnoff fires that were picked up by satellite that day. At >the very least I was able to demonstrate that the oil fire >explanation was plausible. The biggest question was, could the >mid-IR (3-5 micron) radiation travel that far and be detected. I >proposed to the MExican Air Force an experiment using their FLIR >equipped airplane to test the oil field hypothesis, but they >never did it - or at least never told me they had. Their main >argument against the fires was "we never saw them before or >since." This of course, does not rule out the possibility that >unusual atmospheric conditions ocurred on the day of the >sighting. Hi Bruce, I know little about FLIR, but perhaps you can comment on whether this first-order analysis, which doesn't much depend on the FLIR details, holds any water: Whatever the sensitivity of the FLIR may be (in terms of minimum detectable wattage), we must consider whether IR radiation from the atmosphere (essentially a ~300 deg-K black body) would swamp whatever signal might be coming from the oil fields 100 mi. away. The mean spectral radiance of the atmosphere in the 3-5 micron region is ~100 microwatts/sq.cm per steradian per micron of wavelength [Ref.1]. So for an angular field of view of 3 degrees (~.002 steradian), which is roughly the 'medium' field of view setting for the FLIR in question, there will be ~0.4 microwatts/sq.cm of 3-5 micron radiation being received from the atmosphere alone. In order to be detectable, presumably the target of interest must itself produce a non-negligible fraction of this, let's say at least 4 nanowatts/sq.cm (i.e., 1% of the background value). Now consider the two principal mechanisms of radiant intensity loss between the target and camera: geometric (1/R^2) divergence, and atmospheric extinction (scattering and absorption). For geometric divergence: A spherically isotropic source in a vacuum delivering 4 nanowatts/sq.cm from a range of 100 miles would have a total radiant power output of (4 nanowatts) x (4pi x [100mi x 1.61x10^5cm/mi]^2) or ~13 megawatts in the 3-5 micron band. Let's say the earth's surface is a perfect reflector and reduce that by a factor of 2, to ~6.5 megawatts. For atmospheric extinction: The extinction coefficient in maritime air in the 3-5 micron band varies considerably, but the value at 4 microns is characteristic, with a value ~0.055/km [Ref.2]. Applying this value across the entire wavelength band, at 100 miles range the transmitted power is reduced by a factor of EXP(.055/km x 100mi x 1.61km/mi), or roughly a factor of 7000. Hence the total 3-5 micron radiant power at 100 mi. range required to noticeably exceed the atmospheric background radiance at the camera is at least ~7000 x 6.5 megawatts or ~46 gigawatts, which is some 7 times the hydroelectric power output of the Grand Coulee Dam. While it would clearly rule out the oil field flare theory, this number is so enormous that I'm seriously doubting my own calculation. Can you point out where/if I went astray? Not really my area of expertise, so please set me straight if necessary. Thanks Mike  Wolfe L. W., & Zissis, J. G., The Infrared Handbook, Office of Naval Research, Department of Navy, Washington, DC, 1978  Yates, H. W., & Taylor, J. H., "Infrared Transmission of the Atmosphere", U.S. Naval Research Laboratory, 08 Jun 1960 Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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