Electromagnetism is an important indicator of the energy level of matter, as well as the core criterion for its observability, interactability, and structurability. Dark matter and dark energy have low energy levels and possess no electromagnetic properties. According to the second law of thermodynamics, heat can only spontaneously flow from a high energy level to a low energy level, not in the reverse direction. Dark matter and dark energy, lacking electromagnetic properties, are usually in a low-energy, quiet state, making it difficult for them to interact effectively with high-energy observation systems. They cannot emit, reflect, or absorb electromagnetic waves, which is the fundamental reason why they are difficult to detect.

Dark matter has mass, exerts gravitational force, and forms the backbone of cosmic structure, serving as the material basis for the establishment of spacetime. Dark energy has no mass or structure; it only generates cosmic repulsion through negative pressure, driving the accelerated expansion of space.