Hidden Hydrogen

Hidden Hydrogen refers to the concept in astronomy and astrophysics where certain forms of hydrogen, particularly molecular hydrogen (H₂), are not directly observable but are inferred to exist based on other measurements. In astrophysical contexts, hidden hydrogen can affect the dynamics and evolution of galaxies and star formation processes. It often exists in dense regions of gas and dust where traditional observational techniques may struggle to detect it. The term is particularly relevant in the study of dark matter and the overall baryonic (normal matter) content of the universe, as traditional hydrogen detection methods may overlook significant portions of hydrogen present in the early universe or in specific environments. Understanding hidden hydrogen helps astronomers gain insights into the structure and evolution of the cosmos.