Explain an astronomical miracle

The rare sight of Venus crossing the sun is called the transit of venus, which is one of the many events in astrophotography. Many scientific and artistic images are constantly produced from places where transits can be seen: Europe, Africa, North America and Asia. From a scientific point of view, professional astronomical photographers pay attention to science in order to find something from it. From the aesthetic point of view, bus images can be divided into several categories. One theme is to capture transit Venus on a clear solar disk. One focuses on capturing double transits, such as Venus and an airplane or the shadow of Venus and a low-orbit international space station appearing on the sun at the same time. An interesting cloud. For example, the above image was taken from North Carolina, USA. At first glance, the black outline of Venus in the image can easily be mistaken for an unusual little cloud.