Kimmo Huosionmaa
The illusion can be caused by the line of two objects. In this picture, the cloud, what is behind houses seems like smoke, what is rising from burning things. That picture is picture one (Picture I) on the homepage. This kind of illusions causes many kinds of problems in the fire- and other departments of the cities. Optical illusions are fascinating, and they are claimed to cause even death of the travelers. There is a link to the page, where those pictures have been uploaded.
http://kirjabloggaus.blogspot.com/p/two-optical-illusions.html
The classical thing is the phenomenon, called fata morgana, what means the illusion, where the rising air causes the effect of the water in very dry places. And this phenomenon can make a traveler drink too much water, and then the filling of those bottles is not available, but this kind of stories might sometimes from the people illusion.
The fata morgana can see even over the dry and hot streets if the person looks it in the direct angle. If the angle is right, the person would see things like water, and that explains, why children see this phenomenon more often than an adult. But when we are seeing optical illusions, there is another picture in this page (Picture II), and that is about the bubble inside the cloud. This kind of weather phenomenon can cause the alarm of UFO:s. But the thing is actually a bubble of the empty area inside the cloud, and there is no steam inside this bubble. Or the other explanation would be, that there is the darker area in the cloud.
