Other choices of the upstream current correspond to definable boundary conditions. The fact that many numerical calculations appear to disagree with the theory will also be discussed. Measurements of Radio Frequency Emissions on the Galileo Probe Mission into Jupiter's Atmosphere. During the descent, the instrument measured radio emissions in Jupiter's atmosphere in the frequency range 100 Hz - 100 kHz. These signals, whose source is in the Jovian atmosphere, show that in a region of some 15,000 to 20,000 km around the probe entry site, the Jovian lightning was more intense by a factor of about 10 than in cloud to ground discharges on earth, but also less frequent in occurrence by a significant amount.
Most people think of oceans as being a peculiarly Earth-like phenomenon.
However, recent exploration of Europa by the Galileo spacecraft has provided new evidence for a global ocean beneath the very young solid ice crust. In addition, several investigators have proposed that oceans were present in the northern lowlands of Mars in its past history, and new spacecraft data from Mars Global Surveyor are being used to assess the evidence. This talk will focus on how we test ideas for the presence of oceans beyond Earth, what we are learning, and what the implications might be for the history of the planets and the origin and evolution of life. More recently, EUV imaging and spectroscopy obtained with the Extreme Ultraviolet Explorer have provided the first EUV albedo map and spectrum of the Moon. The EUV data reveal complexity in the lunar spectral reflectivity that may provide a useful tool for remote compositional studies and may indicate possible surface fluorescence.