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Conversation2 Listen to a conversation between a student and an administrator in the campus employment office I just transferred from northeastern state university near Chicago. Chicago’s such great city. why did you leave? It was sure convenient to go to a school nearby. But northeastern is still fairly small and it doesn’t have programs I’m interested in. I want to major in international studies. And the only program in the state is here. We do have a great program. And how did you get interested in international studies? My family hosted a few foreign exchange students while I was growing up, then I took part in international summer program after I graduated from high school. I found I really like meeting people from all over, getting to know them. Well, ok, and that led you to our program. Now though, I assume you are looking for a job. A part- time job on campus. I thought I’d save money and being away off the big city. it doesn’t seem to be working that way. Anyway I’ m not having much luck. Most of our campus jobs are taken in the 1th week or to 2 this semester. What work experiences do you have? I was working in the library last year. But I’ve the library here, they said the remaining positions were for work-study students getting financial aid. I’ve never run into(遭遇) that before. About average I say. I helped teach some of the basic classes in northeastern offers for new users. Is that help any? Lecture1 The technology support to apartment needs people to work at a helpdesk. It’s basically a customer service job. It give you chance to develop your people skills. Something that every diplomat needs. They have extended hours. But now they only need people early morning, late nights and weekends. You probably end up with a bit of everything work rather than a regular spot. We are going to start the study of sun spot today. And I think you’ll fine rather interesting. I’ m going to assume that you know the sun spot in the basic terms are dark spots on the sun surface. That ‘ll do for now. The ancient Chinese was the first to record observations of sun spots as early as the year 165. When later Europeans astronomers wrote about sun spots, they didn’t believe the spots were really on the sun. That’s because that they believe at that time that the heavenly bodies, the sun moves stars planet were perfect XX any flom or blemishes. So they believe that the sun spot was actually something else, like shadows of planets crossing the sun’s face. This was thinking of European astronomers until the introduction of telescope, which brings us to our old friends, G. In the early 1600, based on the observation on sun spots, G proposed a new hypothesis. He pointed out that the shape of sun spots, well, the sunspots weren’t circular. If they were shadows of the planet, they would be circular, right? So there’s the problem of prevalent view. And he also knew that the shape of the sun spot changed as seen to moves across the sun surfaces. Maybe a particular sun spot was sort of square. Then later it would come alobsited, then later something else. So, there is another problem with shadow hypothesis. Because the shape of a planetdoesn’t change. What G proposed was that sunspot was indeed a fiture of the sun, but he didn’t know what kind of fiture. He proposed that might be clouds in the atmosphere, solar atmosphere. Especially because they seemed to change in the shape, but there was no predicting the changes. At least nothing G could figure out. That random shape changes would be consistent with spots being in clouds. Over a couple of hundred years, a lot of hypothesis retos around. the spots, or mountains or holes in solar atmosphere throughout the dark surfaces of the sun could be seen. Then in 1843, an astronomer named HS made a interesting claim. S had been watching the sun every day that it was visible for 17 years, looking for evidence of a new planet. And he structed keeping track of sun spots, napping them. So he wouldn’t confuse any potential of a new planet. In the end, there was no planet. But there was evidence that numbers of sunspots increase and decrease in a pattern, a pattern that began repeating every 10 years. That was a huge breakthrough. Another astronomer named W, kept track of the sun for even longer period, 40 years actually. so W did 40 years of research and S did 17 years of research. I think they are lesson there. Anyway, W went all records of very observatory in Europe and put together a history of sunspots observation going back to about 100 years. From this information, he were able to confirm a existence of a pattern, repeating cycle. But W detected a 11 years cycle, not a 20 year cycle. 11 years cycle? Does that sound familiar to anyone? Well, geomagnetic activity. The nature variations of the earth magnet field. It fluctuates in a 11 year cycles. We’ll cover this later in this semester, but for now, scientist of in the late 19 century were aware of geomagnet cycle, when they heard that the sunspot cycle was also 11 years, they decided to find out what was going on. Suddenly everyone was doing studies of the possible relationship between the sun and the earth. Did the sunspot cause the geomagnetic field or did the geomagnetic field cause the sunspot or there is some other thing to cause both? And astronomers did eventually figure out what sunspots have to do with geomagnet fields. Actually, they are magnet firlds. And thefact that sunspots are magnet fields accounts for their dark and appearance. That’s because the magnet fields reduce the pressure exerts on the gases inside of them, make the spots cooler than the rest of the sun surfaces. Uncess, They are cooler, they are darker. |
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