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ExploraTour - Looking at the World in a Different Light


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This is a picture of the sun taken in visible light by the Big Bear Solar Observatory last summer. Take a good long look. You might as well take advantage of this opportunity, because you cannot look directly at the sun in real life without hurting your eyes very badly.

It looks just like you thought it would doesn't it. Except for those two dark spots right near the middle. Those are sunspots.

The sun was very quiet when this picture was taken. At times there are a lot more sunspots on the surface.

Sunspots are places on the sun where solar "storms" may be developing. Solar "storms" are not storms as you know them. They are places where energy is being stored and may be released explosively. Powerful magnetic fields on the surface of the sun suppress the normal convective motions of the solar gases preventing heat from being transported toward the surface. The gas in the sunspots is cooler than the surrounding regions. Because it is cooler it appears darker. If the sunspot were removed from the solar surface and placed in space it would glow more brightly than the moon. Sunspots appear small but are actually as large or larger than the cross-section of the Earth.

These sunspots don't look very impressive. But wait until you see them in other types of light.

The two buttons below show the sun on the same day as the picture you have already seen. The first button is a picture of the sun in a type of red light called Hydrogen-Alpha. In this light sunspots can be seen very clearly. The second button is a picture of the sun in xrays. Xrays are given off by very hot gases high above the visible surface of the sun. In this light, the very hot gases above the sunspots glow brightly.

All of these types of light help scientists understand natural phenomena occurring on the sun.


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Our online store includes fun classroom activities for you and your students. Issues of NESTA's quarterly journal, The Earth Scientist are also full of classroom activities on different topics in Earth and space science!

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA