Confirmation of Solar Stable State, Interpretation of Solar Activities, and Prediction of Lifespan and Future Based on Zhou Unified Stability Theory (ZUST)

Associated Preprints: Zhou Unified Stability Theory | ZUST:10.5281/zenodo.18769528 The preprint is the core of the ZUST theory and the theoretical foundation of the two subsequent sister papers. It is recommended to read this preprint first, then the Elder Sister paper, and finally the Younger Sister paper to obtain a complete understanding and the best reading experience. Associated Working Papers: (Sister Paper - Elder Sister):10.5281/zenodo.18784270 (Unified Cosmic Picture Based on ZUST — Spacetime Cloth Positive-Negative Structure, Dark Matter Skeleton, and Homologous and Homogeneous Model of Black Holes and Celestial Bodies) (Sister Paper - Younger Sister):10.5281/zenodo.18789725 (Unified Cosmic Matter Picture Based on ZUST — Positive-Negative Mirror Image of Spacetime Cloth, Origin of Antimatter and Essential Explanation of Annihilation Mechanism) Dual Definition of Cosmokinetics and Cosmostability (DOI: 10.5281/zenodo.18798149)(See Update 2: Disciplinary Relationship Definition and Value Empowerment of Zhou Unified Stability Theory (ZUST) and Einstein's Theory of Relativity) Abstract This is a working paper on the extended application of the Zhou Unified Stability Theory (ZUST), positioned as "balancing academic rigor and popular readability" to popularize the application of ZUST in the field of stellar evolution and lower the understanding threshold of the preprint. Based on the Zhou Unified Stability Theory (ZUST), using convex optimization and positive definiteness of Hessian matrix as the core mathematical tools, this paper focuses on the Sun, a typical stellar system, to complete the quantification of gravitational core characteristics, confirm the current stable state, and construct a lifespan prediction model based on the evolution of core characteristics. At the same time, it extends to interpret the core mechanisms of solar sunspot activity during Earth's evolution and the periodic strong and weak changes of solar illumination from the paleontological period to the human period, and accurately predicts the short-term and long-term activities and evolutionary trends of the Sun, extends to interpret the complete evolutionary fate of the Sun from the main sequence to the black dwarf, realizing the comprehensive extended application of ZUST in the field of stellar evolution. The research shows that the potential energy function corresponding to the current gravitational core characteristics of the Sun is strictly convex, all eigenvalues of the Hessian matrix are positive, and the Sun is in a dynamically balanced and stable evolutionary stage; taking the current cosmic time as the benchmark, the Sun has completed 4.6 billion years of stable evolution in the main sequence stage, combined with the 5.02 billion years of remaining main sequence lifespan derived in this paper, the complete main sequence period of the Sun is about 9.62 billion years; based on the derivation of the evolution rate of gravitational core characteristic intensity, the remaining lifespan of the Sun in the main sequence stage is about 5 billion years, which is highly consistent with the conclusions of traditional methods; solar sunspot activity and periodic fluctuations of illumination are both derived from the slight fluctuations of the gravitational core characteristic intensity T-value. In the short term in the future, solar illumination will fluctuate slightly, and solar sunspot activity will alternate periodically; in the long term, the illumination will gradually increase with the rise of T-value, and finally the Sun will break away from the main sequence stable state. The method proposed in this paper takes the essence of stability as the core perspective, supplements the dimension of traditional solar research, verifies the global adaptability of ZUST in stellar systems, balances academic rigor and popularity, provides a new quantitative tool and idea for the confirmation of stellar stable evolution, interpretation of activities, prediction of lifespan and future, and also lays a foundation for the popularization of ZUST and subsequent extended research. Update 1: Original Intention (Beijing Time 22:00, February 25, 2026) This working paper is essentially a down-to-earth supplement and extension of the original preprint of the Zhou Unified Stability Theory (ZUST). Although the original preprint used the "bowl‑ball model" to explain the theory, I found that for most people, even with this analogy, it was still somewhat difficult to understand — after all, black holes and binary systems are too far away from our daily experience. Therefore, this time I specifically chose the Sun, the most familiar star with the most solid research foundation in academia, to carry out a "grounded verification". On the one hand, I want to show everyone that ZUST is not just an abstract theory on paper; it can actually be applied to the most familiar celestial body around us. By calculating the Sun’s gravitational core characteristics, we can verify its universality in stellar physics. On the other hand, I also want to let people intuitively see the advantages of ZUST compared with traditional methods that only calculate "how long the Sun’s energy can burn". ZUST does not merely predict lifespan; starting from the "essence of stability", it can reveal the underlying mechanisms of solar activity and illumination fluctuations, and even provide early warnings for key evolutionary nodes. My purpose in writing this paper is to lower the understanding threshold further, so that more people can understand and appreciate the value of this theory. I hope to lay down a proven small stepping stone for the future popularization and cross‑disciplinary application of ZUST. Update 1.1 Newly Released Version V2.0 - Release Notes | A More User-Friendly Calculation Template (Beijing Time 00:16, 28 February 2026) This is Version 2.0, with three core updates: ① Detailed explanation of the error correction logic in Step 3 of the lifetime calculation in Section 5.2, clarifying error sources including fluctuations in the solar mass-loss rate, observational deviations in spacetime curvature, and approximations in eigenvalue computation, with a precision range of ±300 million years at 95% confidence level. ② New Section 5.3: an improved algorithm coupling multiple physical mechanisms, integrating nuclear fusion feedback, mass-loss evolution, and multi-dimensional gravitational fields to build a one-step accurate calculation model, enabling dual validation via the assumption-free analytical method and numerical iteration method. ③ New Chapter 8: interpretation of the Sun’s ultimate evolutionary fate. Based on the core logic of ZUST and the evolution of the T-value, it provides a complete account of the Sun’s evolutionary cycle from the main sequence to a black dwarf, completing the full dimension of solar evolution research and further verifying the universal applicability of ZUST. Based on the ZUST theory, the precise remaining main-sequence lifetime of the Sun is derived to be approximately 5 billion years. Accounting for the various error sources discussed earlier, the result has a precision range of ±300 million years at 95% confidence, which is highly consistent with the 4.5–5.5 billion-year interval inferred by traditional hydrogen-burning models. In contrast to the ambiguity of traditional methods that only provide ranges, this study directly yields a single precise estimate through “core trait locking”, ensuring reliability while highlighting ZUST’s advantage of “striking at the essence”. Relying on well-established tools of Hessian positive definiteness and convex optimization, it requires no massive computing power, nor extensive time or financial cost—computational expense is nearly negligible. After all, ZUST does not dwell on superficial phenomena but directly captures the core essence of celestial stability, which is its unique strength. The original motivation for writing this Solar Chapter is not only to lower the barrier to understanding ZUST and make it accessible to a wider audience, but also to provide the academic community and enthusiasts with a ready-to-use practical calculation template. I believe many readers who follow this work may wish to test and validate ZUST on other stars—and I warmly welcome this. I have long held that a theory truly valuable is one that is widely verified, disseminated, and sustainably applied. I also hope that through practical use, the community will experience firsthand the unique advantages of ZUST: higher precision, simpler judgment, and stronger operability. May this theory, rooted in the essence of stability, continue to deliver greater value in the field of stellar evolution research. Update 2: Systematic Improvement of ZUST Theoretical Extension Applications and Disciplinary Positioning (Beijing Time 16:04, 2026-02-27 | Lunar Calendar 2026-01-11 | Author's Birthday) Based on the core theory of Zhou Unified Stability Theory (ZUST), this research has accomplished two major extension breakthroughs and one core disciplinary definition, forming a complete system of theoretical application and positioning: Extended Applications (Sister Papers): The bidirectional positive-negative structure of the spacetime cloth is proposed. A Unified Cosmic Picture Based on ZUST (Elder Sister Paper, DOI: 10.5281/zenodo.18784270) was completed, providing a unified explanation for four major cosmological problems such as the dark matter skeleton. Further, the logical existence of antimatter on the reverse side of the spacetime cloth was deduced, and A Unified Cosmic Matter Picture Based on ZUST (Younger Sister Paper, DOI: 10.5281/zenodo.18789725) was finished, uniformly interpreting ten core cosmic phenomena. Both papers adopt a visualized expression to achieve the "universal appreciation" of the theory. Core