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For over 100 years, astronomers have known from direct observations that the Sun's surface has a magnetic field that is about twice as strong as the Earth's, but spread out over 10,000 times the area. We don't exactly know where it comes from. It may have been left over from the interstellar cloud that created the Sun over 4.5 billion years ago. Some astronomers think it is actually generated by the Sun itself.
Over all, the Sun's field looks a lot like a bar magnet. It has a north and south polarity as all magnets do. Much of its shape can be seen during a total solar eclipse as it leaves an imprint on the Sun's outer gases, just like iron filings outline the field of a bar magnet. But there is more to the Sun's magnetism than what you might find by just looking at a bar magnet.
Source:NASA
Sunspots have been observed from the Earth by Ancient Chinese astronomers for over 4000 years, but only in the last 200 years have astronomers begun to figure out just what they are. Sunspots are actually intense concentrations of magnetic energy nearly 4000 times stronger than the Earth's own field, or even the Sun's. Somewhere within the Sun's convective zone, perhaps where it bumps up against the deeper radiative zone, conditions are just right for creating jet streams of flowing currents. These currents create ropes of magnetism, which can get concentrated by convective gas flows. When they reach the surface, they pop through and form pairs of sunspots.
The magnetic rope is mostly under the surface, but it forms a loop that emerges from the photosphere to form the two spots. One sunspot always has the opposite magnetic polarity of the other, and they usually follow each other around the surface of the rotating Sun.
Sunspots
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