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Image: "Observation of the Sky." Colored engraving published in 1647 in the book entitled "Selenografia sive Lunae Descriptio" by Johannes Hevelius.
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Bibliotheque Nationale de France, Paris, France.

Understanding the Sky

People have been wondering about what they see in the sky for a long time. Because of our curiosity about the sky, we tell stories and myths about what we see there. Astronomers try to explain what we see in the sky in the simplest way possible.

By carefully watching the sky, astronomers learn about how the universe works. By studying eclipses and the motions of the planets, astronomers eventually realized that gravity controls the way things move, and that gravity was responsible for the motion of the Sun, the Moon, and the stars in our sky as well. We now know that the Earth's motion is responsible for seasons.

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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 by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF