Oct 29 2008
From The Space Library
NASA released data that MESSENGER had gathered as it flew past Mercury on 6 October 2008. At its closest approach, at 4:40 a.m. (EDT), MESSENGER had swooped about 125 miles (201.17 kilometers) above Mercury’s surface. It had taken 1,287 photographs, used the Mercury Atmospheric and Surface Composition Spectrometer to gather data on the atmosphere, and observed the planet’s topography using the Mercury Laser. The spacecraft had studied 30 percent of Mercury’s previously unseen surface during 30 hours of scientific observations. The flyby was the second of three Mercury flybys that NASA had planned for MESSENGER; the first flyby had occurred in January 2008, and NASA had scheduled the third for March 2011. The new observations revealed that Mercury’s western hemisphere is 30 percent smoother than its eastern hemisphere. Scientists described the topography as ancient, heavily cratered, and homogenous. Photographs showed high ridges, indicating that the planet had contracted significantly during its formation, as well as large impact basins and lava flows. Measurements of Mercury’s magnetic field showed that the magnetic field is very symmetric and has strong exchanges of energy with solar wind. MESSENGER also discovered the presence of magnesium in Mercury’s atmosphere and showed that the spatial distributions of calcium, magnesium, and sodium in the planet’s atmosphere are different. These observations would allow scientists to study the interaction between Mercury’s atmosphere and its surface.
NASA, “MESSENGER Spacecraft Reveals More Hidden Territory on Mercury,” news release 08-275, 29 October 2008, http://www.nasa.gov/home/hqnews/2008/oct/HQ_08-275_Messenger_Mercury.html (accessed 8 August 2011); James Dean, “Messenger Sends New Views of Mercury,” Florida Today (Brevard, FL), 8 October 2008; Tariq Malik, “Mercury Flyby Reveals New Oddities,” Space.com, 29 October 2008, http://www.space.com/6035-mercury-flyby-reveals-oddities.html (accessed 11 August 2011).
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