Jets of relativistically moving hydrogen are squirted away from the black hole contained in the microquasar SS433, about an axis that precesses every six months causing a zigzag/corkscrew appearance on the sky in a way that reflects detailed variations in the launch speed and launch angle of the ejected hydrogen. I will describe how the light-travel time effects that give rise to its appearance help determine its distance from us in a very precise way. I will describe how SS433's black hole mass is deduced, and I will discuss other examples of this phenomenon in quasars in the more distant Universe.
Our General Interest Seminars are an opportunity for distinguished speakers to present new research in physics and related areas. The material presented is suitable for undergraduate level upwards and all members of the School are welcome to attend..