The Sun and Its Features

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The Sun and Its Features

Changes in the magnetic field of the sun affect us here on earth in a number of interesting ways. This magnetic field is caused by the flow of electrically charged ions and electrons on the sun, and if it didn't exist, the sun would be a much more boring star. The 11-year cycle of the sun's magnetic field accounts for many of the cool features of the sun: sunspots, solar flares, and aurora borealis. At the beginning of the cycle, the magnetic field is weak and there are very few sunspots; later, at the peak of the cycle, the magnetic field is strong, and there are many sunspots. Sunspots are relatively cool areas that appear as dark patches on the face of the sun. They occur where magnetic field lines are twisted below the surface. The period of time when the magnetic field is strong and there are many sunspots is called a solar maximum. The sun approached one of its solar maximums in the year 2000, and this maximum affected the conditions on earth.

For example, the aurora borealis, or "Northern Lights" we see in the sky are much brighter during a solar maximum. They are also more spread out over the sky. In normal years the northern lights can only be seen over the poles, but during a solar maximum they are visible to much of the northern United States and Europe. Aurora borealis is caused by the solar wind that blows off the corona of the sun. The temperature of the corona is so high that the gravity of the sun cannot hold on to it, so hot charged particles from the corona regularly fly off the sun at millions of miles per hour. When these particles collide with atoms in the earth's atmosphere, they excite their electrons, causing them to "jump" to a higher energy level. When electrons jump to a h...

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...solar maximum), less cosmic rays strike the earth, and when it is weak (during a solar minimum), many cosmic rays strike the earth. Trees record in their rings how much carbon 14 is in the atmosphere, and during the Maunder Minimum tree rings had very high levels of Carbon 14.

Thus, there seems to be a link between the sunspot cycle and the climate of the earth, with solar minimum bringing cooler temperatures and solar maximum bringing warmer ones. This, plus the beautiful displays of northern lights, and the threatening danger of solar flares, are just three ways we are effected by the solar cycle of the sun.

References:

Solar Physics. Hathaway, David H. NASA. March 17, 2000.

Sunspots as Predictors. Younce, Matthew Wiley.

The Sun-Earth Connection. NASA/GSFC. USB/S

Introducing the Aurora. Terry, Kathee and Anderson, Hugh. July 12, 1999.

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