Planets Near Black Holes: Orbital Dynamics, Habitability, and Detection Challenges in Extreme Environments

Abstract

This review paper explores the theoretical and observational landscape of planets orbiting black holes, an emerging field at the intersection of astrophysics, planetary sciences and astrobiology. It delves into how the extreme gravitational, radiative, and relativistic phenomena shape their existence, potential for habitability, and detection. The paper quantitatively describes the significant impact of general relativistic effects, such as time dilation and orbital stability, and analyzes the complex interplay of tidal forces and various radiation sources on potential habitability. It also surveys models of blanet formation within accretion disks and considers scenarios of planetary capture. Finally, the paper highlights cutting-edge observational techniques, including gravitational lensing, X-ray astronomy, and the transformative capabilities of the James Webb Space Telescope (JWST), gravitational wave detectors (LIGO/LISA), and the Event Horizon Telescope (EHT) in pushing the frontiers of discovery. Current theoretical models suggest the possibility of stable blanet orbits and alternative energy sources for life, while observational evidence remains largely indirect, with only a few unconfirmed candidates. The paper concludes by identifying key unresolved questions, particularly regarding blanet formation mechanisms and the connection between primordial black holes and dark matter, emphasizing the profound implications for understanding black holes, dark matter, and the broader search for life beyond Earth.