Astronomy Colloquium

With the advent of the Herschel Space Observatory, following Spitzer, ISO and ground based telescopes, the coverage of the far-infrared to sub-millimeter spectral range becomes extensive. We now routinely observe most astrophysical objects in this range, from cold molecular clouds in our Galaxy to active galactic nuclei in the distant universe, including galaxies of all star formation intensities. Thanks to its unprecedented sensitivity, wavelength coverage and spatial resolution, Herschel has been particularly helpful to reveal the star formation processes, maping for the first time the protostellar cores distribution in Galactic star forming region. Spatial resolution was the key parameter to get SED maps in nearby galaxies to perform detailed energy budget. Sensitivity is such that dusty galaxies can be detected at very high redshift, providing new clues on galaxy evolution. I will highlight some of the results obtained from Herschel observations of Galactic star forming regions, nearby galaxies, and galaxies at high z.