Have you ever thought about the vastness of the universe in which we live? Perhaps you have not given much thought to this subject until now. Even if you have, one can still hardly imagine the huge size of the universe. Let us try to explain how big it really is with an example. What is the biggest width you can think of? the distance from one side of the city you live in to the other may seem pretty big to you. Alternatively, it may well be that you have travelled all the way from the east to the west of your country and couldn't help but be amazed by how big it was. Some of you might have travelled to distant countries. Nevertheless, always keep in mind one important fact! Even if you travelled all around the whole world, that would still be too tiny to help you imagine the enormous size of the universe. That is because the size the Earth occupies in the entire universe barely compares to the size of a speck of dust. This might surprise you, but it is the truth; the planet Earth is only a speck of dust in comparison to the whole universe. Dear children! Now think about our Earth, a tiny speck in this enormous universe. Every day you wake up in your homes on this round ball. The roads that take you to school are also built on it. Now consider this for a moment! If you put toy cars on top of a ball in your hand, would they be able to stay on it? Certainly not. and yet you spend all your day on this round planet, playing and enjoying yourself with your friends without falling off! Now, think about the Sun. How could you warm yourselves, and where would your light come from without this yellow ball of fire? Would you be able to go swimming and have a dip? Would you be able to go on picnics with your family or classmates? Absolutely not! You wouldn't be able to do any of these things, because without the Sun, there would be no living things on Earth. Not only the plants, trees, birds, insects and the pets that you love so much, but also your mother, father, friends, brothers or sisters and even you yourself would not be around. These two examples about the Earth and Sun reveal the importance of the heavenly bodies and their features for our lives. We are going to give you plenty of similar interesting examples in this book. It is very exciting to learn about the universe through these examples. You must also share what you learn with your mother, father, family and friends. They will also enjoy learning about these thought-provoking topics. As you read this book, you will see that Allah our Creator created our universe and all the creatures in it. You will also see that Allah has created the Sun, Moon and Earth and everything in the universe, so that we could lead our lives most enjoyably and comfortably, and to test us and try us. Now, let's start our wondrous journey through the universe.