Our Star Has Spots! People look at stars and study stars all the time; even during the day! In fact, many people who study the stars do not wait until it is dark because they study the star in our own solar system - the sun! The sun is a great star to study; since it is so close we can see many more details than on any other star. One of the details we see are sunspots, small dark regions on the surface of the sun. When we watch every day for years, we can see that sunspots come and go in patterns or cycles. The so-called "sunspot cycle" not only affects the sun, it also affects life here on Earth.

Does it surprise you that our sun has spots? These spots may be seen even without a telescope. They look like dark spots or blemishes on the sun's surface. If you took a picture of the sunspots each day, you would notice that they all move a little bit every day. The sunspots do not really move, that small daily movement is caused by the sun turning on its axis. The sun spins on its axis once every 27 days just as the Earth spins once every 24 hours. We do not know for sure what causes sunspots, but scientists know two things. Each sunspot has a magnetic field that is strongest near the center of the sunspot. They also know that a sunspot is cooler than the rest of the sun; the surface of the sun is about 6000 degrees C and a sunspot may be as cool as 3,000 degrees C.

Sunspots follow some interesting patterns on our star. There is a cycle of pots; during an eleven year period, the number of spots seen on the sun tarts near zero and increases each year until many spots can be seen at nce. Then the number of sunspots decreases slowly each year until there are very few sunspots again. The pattern keeps repeating every eleven ears. Although some cycles have more sunspots than other cycles, the attern does not change. The year 2000 will have many sunspots because it is the peak of the current 11 year cycle. our Star Has Spots! Page 1 of 3 http://www.thursdaysclassroom.com/14oct99/article1.html 21/06/2006 sunspots also have an interesting pattern of where on the sun's surface they
may be seen.

During the minimum of the sunspot cycle, when there are few spots on the sun, most of the spots are located near the sun's north and
south poles. During the maximum of the sunspot cycle, when there are lots of spots on the sun, most of the spots are located closer to the sun's equator. When scientists make a graph of sunspots and where they are located during different parts of the 11-year cycle ,the pattern is beautiful. The graph looks like a butterfly! Something else interesting happens to the sun during the eleven year cycle. The earth has two magnetic poles, the north pole and the south pole. The sun also has two magnetic poles. At the end of each cycle, the magnetic poles on the sun change! The pole that was negative becomes positive; the pole that was positive become negative.