Thanks, everyone, for your comments. A bit more ... Unlike the images on Les Cowley's "Atmospheric Optics" site, the shadow I saw appeared to "arise" out of the ground and "ascend" to the contrail. The time was between noon or 1300 with clear air and unlimited visibility. My wife was driving south. I had only five to ten seconds to view the shadow before it was gone. It appeared to be almost perpendicular to the contrail, instead of parallel to it. I have seen, on many occasions, contail shadows that paralleled the contrail and ones that seemed to show the aircraft chasing its own contrail. This, however, was distinctly different ... hence, my puzzlement. The shadow, contrail, and Sun were almost directly in front of me. The aircraft was no longer in sight. As I remember, I think the alignment is similar to my rough attempt to designate it below. 0 = Sun, / = contrail, | = shadow, ____h_ = horizon, ___ g_ = ground, and > = my eyes. It was the relative angle and the medium against which the shadow was able to be cast that got me wondering. I understand a shadow being cast on a cirrus cloud system, on top of a layer of clouds, but I was driving in almost absolutely CAVU. (Now that I look at the "sketch" below, perhaps you have reasonable grounds to think that I am really "out to lunch," especially if the sketch arrives in your inbox after being completely distorted by the Cyber Monster.) So far, the response that it was the 'Smoke Monster from Lost' appears the most logical explanation. \ <-----------------------------------closest part of contrail extending overhead and behind me \ \ 0 \ | \ | \ | \ | \ | \<-------------------------------farthest part of contrail in the distance in front of me | | _______|__h____ south | /\ _______|__g____ > | ________________________________ From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Monday, May 18, 2009 8:31 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Unusual shadow? Sender ALLOWED [ Remove <https://vq.co.linn.or.us/pk/banner?op=remove_from_allow&From=utah%2Dast ronomy%2Dbounces@mailman.xmission.com&VU=aV47PNhFIWR67juHByvmTQ> ] [ Block <https://vq.co.linn.or.us/pk/banner?op=block_sender&From=utah%2Dastronom y%2Dbounces@mailman.xmission.com&VU=aV47PNhFIWR67juHByvmTQ> ] details <https://vq.co.linn.or.us/userguide/details_allow.html> Vanquish Anti-Spam Control Panel <https://vq.co.linn.or.us/pk/heldemail> Kim, please forgive me but I don't understand this statement at all. Between the contrail and the sun? That's some low-flying jet, or else you were that guy in the lawnchair & weather balloons. On Mon, May 18, 2009 at 6:57 PM, Kim <kimharch@cut.net> wrote:
You almost need to be directly between the contrail and the sun to see such a shadow on the ground cast in the atomosphere itself,
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