May 4 2006
From The Space Library
An international team of scientists led by Giacomo Giampieri of NASA’s JPL reported in Nature the results of their study measuring Saturn’s rotation period. Using magnetic field data collected by NASA’s ESA spacecraft in 2003 and 2004, the researchers estimated that the rotation rate of Saturn is almost 8 minutes longer than the 10 hours, 39 minutes, and 22.4 seconds calculated in 1980. Scientists had based the 1980 measurement on the Voyager spacecraft’s observations of the radio waves generated when solar radiation hits Saturn’s atmosphere. Whereas scientists were able to measure the rotation period of other planets by comparing their magnetic and rotational axes, they could not use this procedure for Saturn, because its rotational axis is nearly identical to the axis of its magnetic field. Instead, scientists had measured distortions in the radio signals that Saturn emits—distortions that they believed were related to the planet’s magnetic field—to estimate the planet’s rotation rate. According to Giampieri, a planet’s rotation rate indicates the amount of centrifugal force acting on the interior of the planet, data that provides “a very important ingredient for planetary modeling.”
Giacomo Giampieri et al., “A Regular Period for Saturn’s Magnetic Field that May Track its Internal Rotation,” Nature 441, no. 7089 (4 May 2006): 62–64; Ker Than, “Length of Saturn’s Day Updated Based on Mystery Signal,” Space.com, 3 May 2006.
The National Research Council Space Studies Board released its study, An Assessment of Balance in NASA’s Science Programs, concluding that NASA “does not have the necessary resources to carry out the tasks of completing the ISS, returning humans to the Moon, maintaining vigorous space and Earth science and microgravity life and physical sciences programs, and sustaining capabilities in aeronautical research.” Study chair Lennard A. Fisk, University of Michigan space scientist and former NASA Associate Administrator, stated that the study committee was “particularly concerned that the shortfall in funding for science has fallen disproportionately on small missions and on funding for basic research and technology. These actions run the risk of disrupting the pipeline of human capital and technology that is essential for the future success of the space program.” The conference report (H. Rep. No.108- 792), which accompanied H.R. 4818 (Pub. L. No.108-447), the bill appropriating FY 2005 funds for NASA, had mandated the study.
Guy Gugliotta, “ NASA Underfunded, Panel Reports,” Washington Post, 5 May 2006; National Academy of Sciences, Office of News and Public Information, “NASA Lacks Resources To Sustain Vigorous Science Program,” news release, 4 May 2006, http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=11644 (accessed 16 March 2010); National Research Council, Space Studies Board, An Assessment of Balance in NASA’s Science Programs (Washington, DC: National Academies Press, 2006), 29, http://www.nap.edu/catalog.php?record_id=11644 (accessed 16 March 2010).
Using images from the HST, astronomers at the Space Telescope Science Institute in Baltimore, Maryland, were able for the first time to witness the birth of a second red spot (dubbed Red Spot Jr.) on the planet Jupiter. The Great Red Spot, which dates at least to the seventeenth century, is a storm rising as high as 5 miles (8.05 kilometers) above Jupiter’s cloud level. The Great Red Spot is large enough to contain two or three planets the size of Earth. The new red spot, roughly half the diameter of the Great Red Spot, had begun as three white ovals—cooler, upper-level storms. Observers had first seen two of the ovals in 1915, and astronomers had seen the third in 1939. The three storms had merged between 1998 and 2000. Astronomers believed that Red Spot Jr., like the Great Red Spot, rises above the top of the main cloud deck on Jupiter. Scientists had theorized that the change in color of the oval to red, which occurred earlier in 2006, was the result of the storm’s exposure to the Sun’s ultraviolet light. They surmised that, when the storm dredged up material deep below Jupiter’s clouds and lifted it above Jupiter’s cloud deck, the Sun’s ultraviolet light chemically altered the material, giving it a red hue. Astronomers also speculated that the HST images could indicate a major climate change in Jupiter’s atmosphere, related to the new spot.
HubbleSite, “Hubble Snaps Baby Pictures of Jupiter’s ‘Red Spot Jr.’” news release STScl-2006-19, 4 May 2006, http://hubblesite.org/newscenter/archive/releases/2006/2006/19 (accessed 26 March 2010); John Johnson Jr., “Astronomers See Spot’s Runt, Clue of Jupiter Climate Change,” Los Angeles Times, 5 May 2006; Space Daily, “Hubble Takes Sharpest Shot Yet of New Red Spot on Jupiter,” 5 May 2006.
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