This paper abandons inconsistent hypotheses in traditional black hole theories, including light trapping by gravity, volume-less singularities and jets driven by electromagnetic force. Based on observational facts and fundamental physical logic, it systematically elaborates the nature of supermassive black holes at galactic centers, the cause of their dark appearance, jet formation mechanism, energy-matter conversion, driving forces of galactic motion and the law of spatial orientation flip. A self-consistent and unified theoretical system is established. The research indicates that a supermassive black hole at a galactic center is essentially a high-energy photon gas within a galactic vortex. It is a pure energy body with no tangible mass, no singular structure and cannot generate gravity itself. Black holes appear dark because visible light entering the high-energy photon gas is boosted into invisible ultra-high-energy radiation, rather than being trapped by gravity. In the early stage, galactic contraction and aggregation are dominated by the gravity of matter. After black holes form and transform into high-energy photon gas, they produce no gravity, while the mutual gravitational force between stars, nebulae, gas, dust and other substances inside the galaxy still exists. Driven jointly by vortex force, rotational inertia and mutual gravitational pull of matter, galactic substances keep converging toward the center and are fully decomposed into pure energy after entering the high-energy photon gas. Black hole jets are generated by rotational compression and pressure relief at the two poles, which are mainly streams of pure high-energy photons. As they travel over long distances and lose energy, new fundamental matter is regenerated, forming a universal cycle between energy and matter. Continuous jet ejection and energy balance adjustment drive the entire galaxy to undergo periodic 180° spatial orientation flip, switching between horizontal and vertical states. This accounts for the diverse orientations of galaxies across the universe. Ultra-long jets extending up to 23 million light-years can traverse galaxy clusters, transporting fresh matter and energy to aging and dormant galaxies, supplementing nebular materials, reigniting star formation and reviving dying galaxies. This theory reasonably explains key observational phenomena such as the jets of the M87 galactic black hole and the 23-million-light-year ultra-long jet of the Porphyrion black hole, as well as the diverse spatial orientations of galaxies. It corrects core misunderstandings in traditional theories and provides new perspectives for the research on black hole physics and galactic evolution.
Jiaqing Yan (Tue,) studied this question.