Tuesday, 6 December 2011

Chapter 10: Constellation

In ancient times, people had to travel day and night in order to reach faraway places. This task was made more difficult because not everyone at the time knew how to read maps or owned a compass. Therefore, during the day they would look out for landmarks such as mountains and rivers to obtain the correct direction. But what about night time, when the land was dark? They were not able to look at the landmarks for directions. So how did they find their way? The answer is the stars in the sky!


What are Constellation
Stars are giant balls of fiery gases, like the sun. They look smaller than the Sun because they are much further away. In the daytime, the sky is lighted up by the Sun. These are other stars in the sky during the day, too, but it is impossible to see them because the sunlight is so strong. Constellations are a group of stars of that seem to resemble something familiar to those who named them. They are not real objects but are just patterns that we see in the sky.
         Constellations have imaginary boundaries formed by connecting the stars. All of the stars within those boundaries are labeled with the name of the constellations. The individual stars in a constellation may look very close to each other, but they are actually separated by huge distances in space and have no real connection with each other at all. The Greeks recognized and named 48 constellations. The constellations have changed over time. In our modern world, many of the constellations have been redefined and now every star in the sky is in exactly one constellation. In 1929, the International Astronomy Union (IAU) adopted official constellation boundaries that defined the 88 constellations known today.  

1 comment:

  1. Pupils are able to understand what are constellation.