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The Winter 2010 issue of The Earth Scientist includes a variety of educational resources, ranging from astronomy to glaciers. Check out the other publications and classroom materials in our online store.
This is a digital copy of an old drawing. It shows the Sun surrounded by four Earths. There are four Earths, one for each season. Original art by ndreas Cellarius (1596-1665).
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(c)1995 Visual Language, All Rights Reserved

As the World Turns

In our time, scientists (and most people!) know that the constellations seem to move across the sky because the earth rotates on its axis. What, you may ask, does the turning of the earth have to do with the constellations' motion across the sky? The answer is that the earth moves in a way that makes it look as if the constellations are moving. It is a case of apparent motion. In the case of the earth and the constellations the earth rotates, with us on it, from west to east. The constellations appear to move from east to west, moving "backwards" from the real rotation of the earth. Actually, instead of saying the constellations rise we should say that the earth has rotated so that we can see different constellations. Then, as the earth continues to rotate the constellations apparently move across the sky. We now know that it is us, on earth, that have moved. As the night progresses constellations that are near or below the ecliptic "set" in the west, we know that the part of the earth we are standing on has turned so that the Earth is blocking our view of the stars that have "set".

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The Summer 2010 issue of The Earth Scientist, available in our online store, includes articles on rivers and snow, classroom planetariums, satellites and oceanography, hands-on astronomy, and global warming.

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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