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Physics and Astronomy of the Moon by Zdenek Kopal download in pdf, ePub, iPad

Otherwise, if the moon covers only part of the sun, we call it a partial solar eclipse. Like the sun, the moon rises in the east and sets in the west with some exceptions for observers in earth's extreme northern and southern regions.

Even without doing any calculations, however, you can just look at a partial lunar eclipse and see that the moon is probably just a few times smaller than the earth. As shown at right, the curvature of earth's shadow on the partially eclipsed moon tells us the size of earth's shadow, in comparison to the moon. Many scenic photographs of the moon are faked, by combining two separate photos. South or southeast No, a crescent moon must be reasonably close to the sun.

But the moon's path crosses the ecliptic roughly twice each month, and a solar eclipse occurs when the sun happens to be there during the crossing. The same thing happens to us every evening after the sun sets, when we still see light in the western sky. Often the entire moon is covered by earth's shadow. Physicists were, in essence, natural philosophers, seeking knowledge of the observable phenomenal world. But even without a telescope, you can use the method of Aristarchus to see that the sun must be many times farther away than the moon.

Although the method is absolutely sound, Aristarchus used rather inaccurate measurements so his numerical answer for the moon's size wasn't especially good. Even then, however, perfect alignment requires that you be somewhere along a narrow path across earth's surface, usually less than km wide. It is not recommended as a foundation for more advanced work in the field. Students should consult members of the department early on in their undergraduate careers in order to plan the most effective course of study.

The moon's new and crescent phases occur when the sun is more or less behind the moon, from our perspective. North or northwest No, the moon is always near the ecliptic.

North or northwest

No, first calculate the number of minutes in a day. This simulated multiple-exposure image shows the positions of the sun and moon with respect to the stars over a nine-day period. First, the moon goes through its complete cycle of phases exactly once each lunar month, that is, in the same time period as its motion with respect to the sun. Wait until the moon is exactly half full, then look up at it. Just looking at these phases, therefore, tells us immediately that the moon must be closer to us than the sun.

The moon's new