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. We interpret what we see in a cultural context through mythology and in the context of science through the laws of the physical universe. The desire to explain what we see around us in the simplest way has driven astronomers for centuries.

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.

Ever more powerful telescopes allow us to "see" further away and thus farther into the history of our Universe. With them, we can study stars and galaxies, as well as many of the more mysterious objects in our Universe. Someday, we may even be able to predict the ultimate fate of the Universe.

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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