What is the phenomenon of smoke overhead?

This is water vapor, and the human body will radiate heat into the air. The air around the body changes its temperature because of such a little heat, so the density of the gas changes. When light passes through a medium with uneven density, it will be refracted, so the shadow will look like smoke.

Smoking in the sun in winter is a natural phenomenon. In fact, it is the transpiration of hot air or sweat that leads to steaming. The head is the meeting of all yang, the head is at room temperature, and all yang meridians follow the head. In winter, the sun shines on the head most easily, and the skin temperature rises most easily.

Extended data:

The benefits of sunbathing to human body

Sunlight overhead can fully promote the absorption of calcium. Many people like to wear hats when basking in the sun. In fact, the sun is not so strong in spring, and wearing thick clothes and a sun hat can't play the role of sunbathing at all. Especially for children, parents are afraid that the sun will burn their delicate skin, so they always wear hats for their children.

In fact, as long as you control the time and let your child's head bask in the sun, it is helpful for the development of the brain and the growth of the skull, and it is also good for the growth of hair. Sunbathing every day also helps to prevent osteoporosis. With the increase of age, calcium in the human body will gradually lose, which will lead to osteoporosis in severe cases.

If you bask in the sun every day, it can help promote the production of vitamin D, which will lead to a slight increase in the calcium content of the human body, so you can avoid or prevent osteoporosis.