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Solar_Rotation_ Pre-lab_01-09-10

Solar_Rotation_ Pre-lab_01-09-10 - Solar Rotation Pre-lab...

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Solar Rotation Pre-lab Read the following introduction to sunspots and solar rotation, then answer the questions that follow. Type your answers directly into the submission box for Solar Rotation Pre-lab on Blackboard, or if you instructor prefers you can submit the pre-lab at the start of the Solar rotation lab. Introduction: Though there are ancient Chinese records of spots on the Sun seen at sunset, the solar disk is generally too bright, and sunspots too small, to be seen with the naked eye. But sunspots are easily seen using a telescope. 1 Thus it is not surprising that Galileo Galilei, who pioneered the use of the telescope in astronomy, was one of the first to publish a series of observations of sunspots that he made with the telescope in 1613. Galileo was quick to recognize that the spots were markings on the visible surface of the Sun, and that they moved as the Sun rotated. Four of his sketches of sunspots, made on four consecutive days, are seen Figure 1. Figure 1- Galileo’s drawings of sunspots as he observed them in June of 1613 2 These sketches clearly show the motion of the sunspots. Note that the detailed appearance of the spots does appear to change---this isn’t due to imperfect drawing skills on the part of Galileo, but due to the variability in appearance of the sunspots themselves. They grow and shrink in size, and spots last a few weeks at most before fading out. The motion of the spots affords us a way of measuring the rotation rate of the solar surface. Solar rotation is one of the principal factors affecting the roughly 11-year cycle of sunspot activity, solar flares, and other phenomena. In the 1860’s Richard Christopher Carrington used sunspots to determine that the period of rotation of the Sun depends on latitude. Spots near the equator of the Sun go around every 25 days, while spots near latitude 45 go around once every 28 days. This so called differential rotation
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