Callisto the Satellite of Jupiter Essay -- Astronomy

It’s easy to see why not much attention is paid to Callisto. For four hundred years, Callisto appeared only as the fourth dot away when gazing at Jupiter through a telescope. It also didn’t help Callisto gain attention by orbiting Jupiter. Jupiter may be one of the most intriguing objects that astronomers have yet to study. Jupiter is the king of the planets. With its complex bands and zones, Great Red Spot, and sheer size, Jupiter has captured our imaginations and has pushed us to learn and explore all we can about it. Now, with our Pioneer, Voyager, and especially Galileo spacecrafts, we have uncovered mysteries of Callisto that give our minds and imaginations quite a workout. John D. Anderson used Radio Doppler data collected by the Deep Space Network from five encounters of the Galileo spacecraft with Callisto. From this data him and his team found that Callisto has a mean radius of 2410.3 km, with no detectable deviation from sphericity. They assembled this data measuring three principle axes, and all three axes were equal to the mean radius with a realistic error of 1.5 km (Anderson et al., 2001). This places Callisto as the third largest satellite in the Solar System, slightly smaller than Mercury, but 1330 km in radius larger than Pluto. Callisto does have an atmosphere. This is not comparable to the atmosphere of Titan or any other planet with a significant atmosphere. Nonetheless, an off-limb scan of Callisto was conducted by the Galileo near-infrared mapping spectrometer in hopes to detect a carbon dioxide atmosphere. Airglow in the 4.26 ÃŽ ¼m carbon dioxide band was indeed observed up to 100 km above the surface. This indicates the presence of a tenuous carbon dioxide atmosphere with surface pressure o... ...820 - 821. Dutch, Steven. "Crater Forms." Natural and Applied Sciences. 10 05. 1999. University of Wisconsin. 07 12. 2005 . Kivelson, M. G. et al. (1999). Journal of Geophysical Research - Space Science, 104, A3, 4609- 4625 Moore J., and Malin M. (1988). Geophys. Res. Lett., 5, 225. Schenk P. (1993). Journal ofGeophysics Research, 98, 7475. Spudis, Paul. The Geology of Multi-Ring Impact Basins. New York: Cambridge University Press, 1993. Thomas, C. and Ghail, R.C.. "The Internal Structure of Callisto." Lunar and Planetary Science 2002: 1196-1197. Thorarinsson, S. (1957) The JÃ ¶kulhlaup from the Katla area in 1955 compared with other JÃ ¶kulhlaups in Iceland. JÃ ¶kull 7, 21-25 Wagner, R., Wolf, U, and Neukum, G.. "Crater Size Distribution on Callisto." Lunar and Planetary Science 2004: 1964-1965.