By imaging polarized light from hot glowing gas near black holes, we are directly inferring the structure and strength of the magnetic fields that thread the flow of gas and matter that the black hole feeds on and ejects. The polarized image from M87’s black hole and the new one from the Milky Way’s black hole look quite similar. So, in the image below, the ring of light you see is glowing gas swirling around the black hole, while the dark center is called the black hole’s shadow.