 Here we are zooming into M87, the dominant galaxy at the center of the Virgo Galaxy cluster. It's a huge elliptical galaxy that contains several trillion stars. The steady increase in brightness of M87 towards its center is readily apparent in the image, showing that the stars in M87 are strongly concentrated towards its nucleus. Note the jet of material streaming out from the center. This indicates that the galaxy has an active galactic nucleus, AGN for short. That is, it has a supermassive black hole at its center that is accumulating large amounts of matter from an accretion disk. In 2019, the Event Horizon Telescope released an image of this black hole, the first ever image of a black hole. We'll cover this black hole and its image in a bit, but first, we'll take a deeper look at this jet. It provides information on our line of sight orientation and explains some of the physics needed to fully understand the black hole's image. We've known about the jet of plasma shooting out from the core of M87 since 1918, when astronomer Herbert Curtis saw a ray of light connected to the galaxy center 5,000 light years long and 2 light years wide. Several things stand out about this jet. It's blue, it's very bright, it consists of chunks or knots, and it terminates in a plume. You may have also noted that there is no counter jet going out the other way, like we've seen in other galaxies. The jet is understood to have been formed in a strong magnetic field created by the interaction between a spinning black hole and the rotating accretion disk. Then, at the point where matter from the accretion disk is crossing the Event Horizon into the black hole, a small percentage of the charged particles are swept into this magnetic field and ejected into the jet at the black hole's escape velocity, which is near the speed of light for objects as massive as a black hole. These escaping particles are forced into circular orbits around the strong magnetic field. These circularly accelerating ions create electromagnetic radiation across a wide spectrum, including radio, visible, and x-ray light. This is what we are seeing with our radio, optical, and x-ray telescopes. It's called synchrotron radiation, and it's well understood because it's the same as the radiation from synchrotron particle accelerators we build here on Earth.