Dane Stevens, age 11, of Santa Maria, California, for his question:
How deep do sunspots go?
The surface area of a mayor sunspot may be at least a million square miles. Its high energy eruptions can span 93 million miles to reach and disturb the upper atmosphere of the earth. But astronomers cannot tell us how deep these disturbances go down below the face of the sun. If they knew this, they could tell us what causes sunspots. If they knew what causes the, they would be able to tell us at what level they begin.
All the evidence suggests that sunspots boil up from below the surface. Photographs show the average spot to be a darker blob on the dazzling face of the sun. The darkness is caused by a somewhat lower temperature. The pattern shows an eddying vortex, with the darkest region in the center. It certainly looks like a seething outburst bubbling up from below. What's more, from time to time a sunspot erupts enormous flares of charged particles out into space.
Other evidence is related to the intense magnetic fields that go with a sunspot. Electricity is the motion of electron particles and an electric current always surrounds itself with a magnetic field. On the sun, an erupting vortex of electrically charged particles would be likely to surround itself with an enormous magnetic field.
All this evidence suggests that sunspots do indeed well up from below. But astronomers cannot say at what level the disturbance occurs. The bottom of a sunspot may be dust below the surface or it may be down in the fiery core of the sun, perhaps thousands of miles below the surface. .
Many other questions will be answered when we know how and why these stormy rashes appear and disappear on the face of the sun. Usually they form in pairs, within fairly narrow belts north and south of the sun's equator. One leads the other and if the lead spot has a negative charge the following spot has a positive charge. The positive negative pattern reverses south of the equator. The whole thing reverses when one sunspot cycle ends and a new one begins.
These sunspot cycles are another baffling mystery. For a period of about 11 years, the number of sunspots increases and decreases. The cycles are separated by a year of minimum sunspots. Year by year the numbers increase and at peak production there may be 100 tames more. At present, nobody can say why this occurs, or why the mighty magnetic forces of a sunspot behave as they do.
In any case, a sunspot upheaval is stupendous and quite in keeping with what we would expect from the super stupendous sun. The sun's densely packed gases contain more than 99 per cent of all the material in the Solar System. Their temperatures seeth and the fiery core is a continuous nuclear powerhouse. Every second day and night it converts four million tons of hydrogen fuel into nuclear energy. Compared with this activity, a few surface sunspots must seem like minor upsets.