Astronomy: Understanding the Universe

Astronomy: Understanding the Universe — page 1
illions of lucky people in Africa and Asia had the opportunity to witness an unusual celestial event on January 15 2010 Using special dark glasses pinhole cameras and other devices so that they would not be blinded by the Sun they saw a rare annular solar eclipse This kind of eclipse takes place when the Sun is clos est to Earth and the Moon is farthest away so the Moon does not completely cover the Sun This means that at the peak phase of the eclipse the rim of the Sun is visible all around the disk of the Moon The peak phase of the January 15 eclipse lasted 11 minutes and 8 sec onds Such a duration for an annular solar eclipse will not be exceeded until the year 3043 The subject of eclipses is just one of the many fascinating topics you will learn more about in this volume Early Egyptians and Chinese used their eyes to study the annual patterns of the sky carefully enough to make accurate calendars During the 2nd century AD the Egyptian astronomer Ptolemy formulated his geocen tric Earth centered model of the universe now known as the Ptolemaic system It was not until the 1500s that the Polish astrono mer Nicolaus Copernicus determined that OIO