演講資訊

摘要：

At the onset of the current century, the prevailing belief among astronomers was that solely super-Alfvenic turbulence could rival gravity in the process of star formation. This perspective gradually evolved during the second decade, as polarized thermal dust emission implied a significant level of organization in magnetic fields (B-fields), signifying dynamically strong B-fields and thus anisotropy in both turbulence and gravitational collapse. On the other hand, the relation between the magnetic field (B) and density (n) deduced from Zeeman measurements, expressed as B~n^2/3 , has been interpreted as isotropic gravitational collapse — a consequence of dynamically weak B-fields. The contradiction between the two B-field tracers remains a major mystery (see, e.g., the latest PPVII review chapter). The logic and data behind the above statement will be discussed, followed by my solution to the mystery, which depends on a turbulence-density relation.