William Atkins
Friday, 01 May 2009 21:10
Science -
Space
Page 2 of 4
In addition, a U.S.-Czech Republic team stated in its parallel Science article
MESSENGER Observations of Magnetic Reconnection in Mercury’s Magnetosphere that
“Solar wind energy transfer to planetary magnetospheres and ionospheres is controlled by magnetic reconnection, a process that determines the degree of connectivity between the interplanetary magnetic field (IMF) and a planet’s magnetic field.”
In other words, the IMF is the Sun’s magnetic field that is carried by the solar wind out to Mercury and the other planets in our Solar System.
The team adds,
“During MESSENGER’s second flyby of Mercury, a steady southward IMF was observed and the magnetopause was threaded by a strong magnetic field, indicating a reconnection rate ~10 times that typical at Earth. Moreover, a large flux transfer event was observed in the magnetosheath, and a plasmoid and multiple traveling compression regions were observed in Mercury’s magnetotail, all products of reconnection.”
In other words, there is a big interplay between the Sun’s magnetic field and Mercury’s magnetic field. In fact, Mercury’s pattern of connectivity (the interplay between its magnetic field and the Sun’s) is ten times that of the Earth-Sun’s pattern.
Even though Mercury's magnetosphere is much smaller than Earth's, the planet is much closer to the Sun than Earth--which contributes to its magnetic connectivity being much larger.
Sean Solomon (Carnegie Institution of Washington), the principal investigator for the mission, states,
"This second Mercury flyby provided a number of new findings. One of the biggest surprises was how strongly the dynamics of the planet's magnetic field-solar wind interaction changed from what we saw during the first Mercury flyby in January 2008."
The research team concludes,
“These observations indicate that Mercury’s magnetosphere is much more responsive to IMF direction and dominated by the effects of reconnection than that of Earth or the other magnetized planets.”
Page three talks about the Rembrandt impact basin on Mercury's surface.
