SO colloquium: X-ray Polarimetry: a New Window to the Universe

Polarimetry is a very important technique for understanding magnetic fields and high-energy processes in the Universe. While we have been studying polarization in the radio and optical side of the electromagnetic spectrum for decades, what happens at higher energies has, until recently, eluded us. In 2021 NASA finally launched the first X-ray polarimeter, the Imaging X-ray Polarimetry Explorer - IXPE, offering us a completely new window to the Universe, and the tools to study astrophysical systems from a radically different perspective. I will discuss results from IXPE's first two years of observations on a plethora of astrophysical systems from very compact magnetars and X-ray binaries to the biggest black holes in the Universe in radio galaxies and blazars.