When you look at the sky on a clear night, you can see dozens, perhaps even hundreds, of tiny points of light. Almost every one of these points of light is a star, a giant ball of glowing gas at a very, very high temperature. Stars differ in size, temperature, and age, but they all appear to be made up of the same elements and to behave according to the same principles.  People of many different cultures, including the Greeks, identified patterns of stars in the sky. We call these patterns constellations. Figure 1.1 shows one of the most easily recognized constellations. Why do the patterns in constellations and in groups or clusters of stars, called asterisms, stay the same night after night? Although the stars move across the sky, they stay in the same patterns. This is because the apparent nightly motion of the stars is actually caused by the rotation of Earth on its axis. The patterns also shift in the sky with the seasons as Earth revolves around the Sun. As a result, people in a particular location can see different constellations in the winter than in the summer. For example, in the Northern Hemisphere Orion is a prominent constellation in the winter sky, but not in the summer sky. This is the annual traverse of the constellations.  Although the stars in a constellation appear close together as we see them in our night sky, they are not at all close together out in space. In the constellation Orion, the stars visible to the naked eye are at distances ranging from just 26 light-years (which is relatively close to Earth) to several thousand light-years away. Click image to the left or use the URL below. URL:  There is no reason to think that the alignment of the stars has anything to do with events that happen on Earth. The constellations were defined by people who noticed that patterns could be made from stars, but the patterns do not reflect any characteristics of the stars themselves. When scientific tests are done to provide evidence in support of astrological ideas, the tests fail. When a scientific idea fails, it is abandoned or modified. Astrologers do not change or abandon their ideas. Click image to the left or use the URL below. URL:
When you look at the sky on a clear night , you can see dozens , perhaps even hundreds , of tiny points of light . Almost every one of these points of light is a star , a giant ball of glowing gas at a very , very high temperature . Stars differ in size , temperature , and age , but they all appear to be made up of the same elements and to behave according to the same principles . People of many different cultures , including the Greeks , identified patterns of stars in the sky . We call these patterns constellations . Figure 1.1 shows one of the most easily recognized constellations . Why do the patterns in constellations and in groups or clusters of stars , called asterisms , stay the same night after night ? Although the stars move across the sky , they stay in the same patterns . This is because the apparent nightly motion of the stars is actually caused by the rotation of Earth on its axis . The patterns also shift in the sky with the seasons as Earth revolves around the Sun . As a result , people in a particular location can see different constellations in the winter than in the summer . For example , in the Northern Hemisphere Orion is a prominent constellation in the winter sky , but not in the summer sky . This is the annual traverse of the constellations . Although the stars in a constellation appear close together as we see them in our night sky , they are not at all close together out in space . In the constellation Orion , the stars visible to the naked eye are at distances ranging from just 26 light - years ( which is relatively close to Earth ) to several thousand light - years away . Click image to the left or use the URL below . URL : There is no reason to think that the alignment of the stars has anything to do with events that happen on Earth . The constellations were defined by people who noticed that patterns could be made from stars , but the patterns do not reflect any characteristics of the stars themselves . When scientific tests are done to provide evidence in support of astrological ideas , the tests fail . When a scientific idea fails , it is abandoned or modified . Astrologers do not change or abandon their ideas . Click image to the left or use the URL below . URL :
in winter and in summer, people in a given location see
in winter and in summer , people in a given location see
different constellations.
different constellations.