Have you noticed? From the universe outside the Milky Way to hurricanes, from the vines of climbing plants to the skins of thistles, pineapples and pinecones, from the patterns on nautilus shells to the arrangement of sunflower seeds, from the cell structure of the human body to the flowers and fruits of cauliflower, these beautiful shapes have a mysterious regularity, which is in sharp contrast with the chaotic world around them. What kind of mathematical laws does this familiar structure contain? In fact, all these things mentioned above have a common feature, that is, they all have a curved shape like the texture of a snail's shell, called a spiral.

Spiral structure is the most common shape in nature, which is found in DNA and many other microstructures found in biological cells. However, why does nature prefer this structure so much? Physicists in Pennsylvania, USA, found the mathematical answer to this question.

Why is the spiral structure like this? The answer in the past was-determined by the attraction between molecules. But this can only answer how the spiral structures are formed, but not why they are in that shape. Randall Kamen, a professor of astronomy and physics at the University of Pennsylvania, pointed out that in essence, spiral structure is a better way to aggregate into very long molecules, such as DNA, in crowded spaces, such as cells.

In the dense environment of cells, long molecular chains often adopt regular spiral structure. This not only allows information to be closely combined with it, but also forms a surface with which other particles can be combined at a certain interval. For example, the double helix structure of DNA allows DNA transcription and repair.

In order to show the importance of space to the spiral formation, Carmen established a model, in which a tube that can be deformed at will without breaking is immersed in a mixture of hard spheres, just like a molecule in a very crowded cell space. Through observation, he found that for such a short and deformable tube, the formation of ц-shaped structure requires the least energy and the least space. The ц-shaped structure in the spiral is most similar to the spiral in nature in geometry.

It seems that the spiral structure in molecules is an example of nature's best use of materials in its hands. DNA adopts double helix structure because of the space limitation in cells, just as the design of spiral stairs is due to the space limitation in apartments.