Uranus three years after Voyager

Research of the planet Uranus by Voyager 2 started in November 1985. Knowledge obtained from the probe is summed up: The planet's axis of revolution lies in the plane of the orbit, atmospheric flow is given by the planet's rotation with predominant eastern flow and is concentric around the poles. Above the layer of clouds there is a thin hydrogen envelope with a temperature of up to 750 K. Above the illuminated part of the planet there is an ultraviolet emission in the range of 50 - 170 nm. Rotation time of the planet is 17 hrs 14 mins. The planet probably consists of a solid core submerged into an extremely dense atmosphere consisting of methane, ammonia, hydrogen and ice where the temperature of the upper layers reaches 50 to 300 K. The planet has 15 moons and 11 rings. The material of the rings and inner moons is extremely dark. Interesting photographs were obtained of the surface of the moons from which may be derived the origin and history of these satellites. The planet's magnetic field is extremely complex. (M.D.). 3 figs