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We now offer the Cool It! card game in our Science Store. Cool It! is the new card game from UCS that teaches kids about the choices we have when it comes to climate change.
This is a diagram of a typical solar eclipse. During a total solar eclipse, the umbra reaches the Earth. During an annular eclipse, it does not. An eclipse occurs when the Moon passes in the path of the Sun and Earth.
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Solar Eclipses

An eclipse of the Sun occurs when the Earth passes through the Moon's shadow. A total eclipse of the Sun takes place only during a new moon, when the Moon is directly between the Sun and the Earth and is positioned just right to cast a shadow on the Earth.

When a total eclipse does occur, the Moon's shadow covers only a small portion of the Earth, where the eclipse is visible. As the Moon moves in its orbit (at 1 km/s), the position of the shadow changes, so total solar eclipses usually only last a minute or two in a given location.

In ancient times, people were frightened by solar eclipses (even back then people realized that the Sun was essential to life on Earth). Now eclipses are of great interest to the public and to solar astronomers. Eclipses provide an opportunity to view the Sun's outer atmosphere, the solar corona.

Because eclipses occur infrequently, solar astronomers have built special instruments called coronagraphs to view the Sun. Coronagraphs block out ("occult") the light coming from the photosphere, allowing the light scattered from the corona to be viewed.

If you ever get to view a solar eclipse, make sure to never look at the Sun directly! Always use one of these safe techniques.

Last modified April 27, 2006 by Randy Russell.

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Cool It! is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store.

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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