2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/9723We demonstrate that there is only one physical process required to explain the spectrum and the variability of the radio source at the dynamical center of our Galaxy, Sgr A*, in the frequency range from $\approx$1 to $\approx$1000 GHz, namely optically thin synchrotron radiation that is emitted from a population of relativistic electrons. We attribute the observed variability to variable energy input from an accretion disk around Sgr A* into the acceleration of the electrons.6 pages, 2 figures, A&A-TeX, uuencoded file with PostScript files of the paper and the figures Max-Planck-Institut fuer Radioastronomie (Bonn, Germany) Preprint Series No.566 accepted for publication in Astronomy and AstrophysicsAstrophysicstext