astronomers have discovered and cataloged billions of galaxies. The exact number is difficult to determine due to the vastness of the universe and the limitations of our current observational capabilities. The number of known galaxies continues to grow as technology improves and observational methods advance. It's worth noting that new surveys and telescopes, such as the upcoming Vera C. Rubin Observatory, are expected to revolutionize our understanding of the universe and reveal even more galaxies in the future. For the most up-to-date information, it is recommended to consult astronomical databases and scientific literature.