What are the zodiac signs? Will the sun ever stop shining?

  When you look at the stars on a clear night, you may notice that many of them look as if arranged in groups or patterns. In ancient times too our ancestors observed them and named them according to their shapes. It was also noticed that certain groups or shapes appeared at certain months of the year and were replaced by other groups during other months or seasons. They followed certain cycles and paths.

Twelve shapes which we now know as constellations were prominent. The sun and the moon always rose and set within the part of the sky that held these twelve. The part of the sky through which these stars and planets moved was named the zodiac which means the circle of living things. The constellations were named after living things. The twelve constellations were called the signs of the zodiac. These are Aries the ram, Taurus the bull, Gemini the twins, Cancer the crab, Leo the lion, Virgo the virgin, Libra the scales, Scorpio the scorpion, Sagittarius the archer, Capricorn the goat, Aquarius the water carrier, Pisces the fish.

Will the sun ever stop shining?

Scientists tell us that after about five billion years the sun will begin to die, just as all stars do. First, the sun will get hotter. Then it will probably swell up. Slowly it will become much, much bigger. As it grows bigger, it will pour out more heat. The earth will become so hot that all the rivers, ponds, lakes and oceans will boil and turn into steam. All plants and animals will die.

After about a billion more years, the sun will start shrinking. It will become smaller and smaller. The colour will change from red to white. Its brightness will fade. It will become cooler and smaller, and finally be a dead, black ball, a little smaller than the Earth.

When the heat given by the sun starts reducing, the clouds of steam around the earth will turn back into water and fall as rain. Oceans and lakes will fill up again. But as the sun grows cooler, the earth will also grow colder. All the water will freeze. Earth will become a lifeless ball of rock and ice cold, dark and silent.

Why does the moon shine?

The moon is our nearest neighbour in space. It is only about 239,000 miles away, while the stars are billions of miles away from us. The moon is a ball of grey rock, some of which is covered with dust. It has no air or water, and no plants or animals. The whole surface is nothing but mountains and plains of rock. It isn’t a ball of hot, glowing gas, like the sun. Then why does it shine so brightly?

The light that it sends to Earth for us to see is the sunlight that is reflected towards the Earth. The moon acts like a giant mirror. But it isn’t really a very good mirror. It isn’t smooth and shiny. The rocks on the moon are mostly rough and dark grey. So it doesn’t reflect much sunlight. But whatever little is reflected, is so bright that it makes the moon look like a sliver ball floating in the sky.

Why do stars twinkle?

Stars actually shine with a steady glow, just as the sun does. But when we look at them they seem to twinkle. Because, when the light from stars reaches our atmosphere it gets bent several times by layers of moving air. If you see them from outer space from outside the earth’s atmosphere they would not twinkle but look like bright objects.