Today on Galileo - November 5, 1996
After successfully studying Callisto yesterday, Galileo spends much of today observing Jupiter, at a distance of only 875,000 km (or 12 lengths of Jupiter's radius). Early in the day, the spacecraft will actually fly through Jupiter's northern auroral zone. Some lines of Jupiter's magnetic field cause plasma (hot ionized gases) to be driven into Jupiter's atmosphere and cause aurora. Galileo will for the first time actually pass through these lines and the imaging camera, UVS, PPR and Fields and Particles instruments will take measurements together that can help us understand why the aurora happen. The imaging camera (visible wavelengths), NIMS (infrared, to determine atmospheric composition), PPR (infrared, to determine atmospheric temperature), and UVS (ultraviolet, to determine chemical makeup) instruments will spend most of the day studying transition regions between wind belts of different directions. These will cover a full Jupiter rotation (10 hours) to measure cloud movement and wind patterns. Amalthea will be imaged this afternoon, Jupiter's largest minor moon, and third closest to the planet. Amalthea is only 135 kilometers (84 miles) across. The day ends with monitoring of Io's hot spots by NIMS, PPR, and the imaging camera.