Amazing world of stars
Every one of us had sung the rhyme – twinkle twinkle little star, how I wonder what you are ... numerous times during our childhood, isn’t it? Apart from featuring in our nursery rhymes, stars have been important to civilizations throughout the world. They have been part of various religious practices and used for celestial navigation and orientation. Many ancient astronomers believed stars were permanently affixed to a heavenly sphere, and that they were immutable. By convention, astronomers grouped stars into constellations and used them to track the motions of the planets and inferred the position of the Sun. The motion of the Sun against the background stars (and the horizon) was used to create calendars that in turn regulated agricultural practices. The currently used Gregorian calendar is a solar calendar, based on the angle of the Earth's rotational axis relative to its local star, the Sun. Let ...