The amount of sodium, silicon, and oxygen ions measured in the magnetosphere of Mercury is very high. The ions could either have been blown directly by the solar winds from the planet's surface or at least come from the exosphere, the outermost layer of the atmosphere, the researchers suspect. Another peculiarity are the changing with the day and night concentrations of ions, which are likely to be due to the interaction of the magnetic field with the solar wind, the scientists report.
Because of its close proximity to the Sun, Mercury is difficult to study from both the earth and probes. In January 2008, the spacecraft Messenger reached the sun's closest planet of the solar system. Messenger is only the second probe to visit Mercury after the Mariner 10 spacecraft 33 years ago. Mercury's internal magnetic field was discovered during the first exploration, and scientists have been speculating about the interaction of the solar wind with the magnetosphere and the surface of Mercury ever since.
When analyzing the Messenger data, scientists from various research teams also discovered that volcanic activity has shaped the planet much more than previously thought. Thus, researchers discovered surface formations that point to volcanoes, lava flows and strong volcanic eruptions. displayThomas Zurbuchen (University of Michigan at Ann Arbor) et al .: Science, Vol. 321, p. 90 ddp / science.de? Uwe Thomanek