One way to determine that this satellite image represents the winter solstice is to look at the position of the sun in the image. During the winter solstice, the sun is at its lowest point in the sky, resulting in shorter days and longer nights. This can be observed in the satellite image by the shorter length of sunlight on the ground compared to the shadows. Additionally, the image may show snow-covered areas or winter weather patterns, further indicating that it is the winter solstice.
