Have you ever seen a cloud like this in the sky? No? Neither have we. This was spotted last Wednesday (October 7, 2009) over Moscow according to this English Pravda article. They even have a video recording for it. Here's a Russian meteorologist's interpretation:
This is purely an optical effect, although it does look impressive. If you look closer, you can see sun rays coming through that cloud. Most likely, the sun was setting when the video was being made. If you observe clouds regularly, you may see many other astonishing things. Clouds of the same class may look absolutely different in different areas. Several fronts have been passing through Moscow recently, there was an intrusion of the Arctic air too, the sun was shining from the west – this is how the effect was produced.As an amateur cloud watcher myself, I agree that there are many astonishing things in the sky and they are certainly do look different in different areas. One can always come up with plausible or otherwise explanations for the astonishing thing people see. But one thing can be quite certain is that they seldom repeat a peculiar appearance. In this day and age, one can always capture the freaque cloud things in the sky, whether or not there might be likely explanations but a handy digital or video camera can always be get set and ready to shoot!
I think it's good that it was happened over Moscow. If it were happened over Washington D.C. you can be sure to hear that it was most definitely Obama's halo that got away and the photographer will be on Oprah in no time! Wait a minute, how could Obama lost his halo?