Research Paper on:
Past and Present in the Nighttime Sky

Unformatted Sample Text from the Research Paper:
The function of astronomical bodies and their relation with one another has undoubtedly fascinated mankind since the beginning of our reign on earth.  Our understanding of astronomy has progressed from mythical explanations to explanations based in scientific fact. Even in the face of this scientific understanding, however, there is often confusion about  the intricacies of astronomical events. Eclipses present an excellent example of this confusion. While we perceive eclipses as occurring in a precise relationship, sometimes our intuition as to  how they occur can be wrong. Consider the question, for example, of how many times a year an eclipse can occur. To answer this question accurately we must  progress beyond the simple observation that solar and lunar eclipses occur because the earth and the moon are orbiting in relation to the sun. If the orbits of either  the earth or the moon were tilted to an extreme eclipses would not occur. Just a slight tilt in these orbits would result in only partial eclipses. The  frequency of these eclipses is determined by the number of times one bodys orbit finds itself in between the second bodys orbit and the sun. Because the moon makes  a complete circle of the earth every month and the earth revolves the sun every year, however, you could theoretically have twenty-four eclipses a year. This does not occur,  because as explained above these orbits do not occur in a completely flat plane. Instead, the moons orbital plane is tilted in relationship to the earths orbital plane.  Consequently, eclipses can occur only at a new or full moon (when the earth, moon, and sun are aligned) or at a node where the orbital planes of the moon