The Sun has strong magnetic fields as represented by sunspots. The mechanism to create such strong magnetic fields is still a mystery, and is one of the most important problems in astronomy. Such magnetic fields on the surface of the Sun are known to drive dynamic activity such as solar flare, and eruptions which in turn can lead to geomagnetic disturbances that can have influence on the Earth and thereby on humans. Studies of the Sun, in particular, of its magnetic fields, are critically important in this respect too.

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More info: Hinode web page