Description: This repository contains a speculative essay and a numerical simulation exploring the idea that gravitational fields and a quantum phase jitter (motivated by the Unified Applicable Time, UAT, and the Unified Causal Principle, UPC) act as a natural filter that scrambles weak, information-rich artificial signals while preserving strong periodic beacons like pulsars. The Fermi paradox is reinterpreted not as an absence of civilizations, but as a fundamental limit on the coherence of interstellar communication. Contents: LaTeX source and compiled PDF of the essay "The Gravitational Phase Filter". Python script (filter_simulation.py) that generates the illustrative figure comparing a weak modulated signal with a strong pulse train under increasing phase jitter. Theoretical background: UAT: https://doi.org/10.5281/zenodo.17729221 UPC: https://doi.org/10.5281/zenodo.17718670 Note: This work is an exploratory intellectual exercise, not a peer-reviewed scientific paper. It is shared as a conceptual contribution to the debate on the Fermi paradox and the limits of signal propagation in a causally regulated universe. Author: Miguel Ángel Percudani (Puan, Buenos Aires, Argentina) License: Creative Commons Attribution 4.0 International (CC BY 4.0)