A Dual Matter–Radiation Conversion Cycle Involving Stars and Black Holes

Stars and black holes are commonly treated as fundamentally different astrophysical objects: stars convert matter into radiation via nuclear fusion, while black holes are considered end points of gravitational collapse and accretion. In this work, we propose a complementary interpretation in which stars and black holes represent opposite nodes of a cosmic matter–radiation conversion cycle. While stars dominantly realize the process matter → radiation, the environments surrounding black holes enable the inverse process radiation → matter through well-established photon–photon interactions, such as electron–positron pair production. The resulting massive particles possess proper time and gravitational coupling, leading to preferential infall into the black hole, while excess energy is released as radiation or relativistic outflows. This hypothesis does not introduce new fundamental physics but offers a unifying conceptual framework linking stellar fusion, pair production, and black hole accretion into a closed conversion cycle.