What is true of sunspots?

A. They are hotter than the rest of the solar surface.


B. They occur at random intervals.


C. They are correlated with a number of terrestrial effects.


D. They are dark clouds floating in the solar atmosphere.

What is true of sunspots?
None of these are completely true, but B is the most correct.





Sunspots are cooler than the surrounding surface (which is why they appear dark in comparison).


They aren't completely random, they appear in a reasonably predictable 11-year cycle, the number, exact location, and intensity is the random part.


C. sounds right, but it depends on how you interpret the statement. If you mean that sunspots *cause* terrestrial effects, then that is true - auroras are more common and bright during sunspot maximums, and radio and electronic instruments can be affected by the magnetic fields if the sunspot releases a coronal mass ejection or increased solar wind. But if you mean the sunspots are *caused* by terrestrial events, then not at all.


D. is not true at al.
Reply:Sunspots are cooler than the rest of the photosphere, which is at 9900F, while sunspots run around 8000 to 8500F.


They occur on a moderately regular schedule in an approximately eleven year cycle.


Numerous effects on the Earth are correlated with numbers and appearances of sunspots, such as rainfall, temperatures, the strength of the ionosphere, etc.


There are clouds in the solar atmosphere, but they are extra hot and bright.


So A, B, and D are shown to be false, while C is true.
Reply:C.


A sunspot is a region on the Sun's surface (photosphere) that is marked by a lower temperature than its surroundings and has intense magnetic activity, which inhibits convection, forming areas of low surface temperature. Although they are blindingly bright at temperatures of roughly 4000-4500 K, the contrast with the surrounding material at about 5800 K leaves them clearly visible as dark spots. If they were isolated from the surrounding photosphere they would be brighter than an electric arc. As of 2006, we are near the minimum (predicted for 2007) in the sunspot cycle [1]. Sunspots are often related to intense magnetic activity such as coronal loops and reconnection.
Reply:sunspots are regions on the sun that are cooler than the rest of sun's surface and where the magnetic field is stronger.
Reply:Actually, Sunspots are cooler than the rest of Sun!
Reply:A

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