The first thing any good explorer needs to know before exploring anywhere is where he or she comes from. So, before we go anywhere, let's find out about where you live.
You might not believe me, but you live on a ball of rock which is
floating in a mostly empty space. This ball of rock is covered in water, with small bits of
land sticking out of this water. You are not alone on this ball of rock. In
fact, last time somebody counted, they added up that about 6,446,131,400*
also live on this ball. As well as these 6 billion people, there are
thousands of millions of animals living on the same ball of rock, some living on
the land, some living in the water, some smaller than the eye can see, some as
big as a house. Some of these people and animals live on the top of the ball of
rock, some of them live on the bottom of it, yet they don't fall off! You must
be thinking that this ball of rock must be very big for all of this to be able
to exist together. And you would be right. However, when we talk about space, the ball of rock that you
and 6 billion other people live on is actually tiny, as we shall discover later.
The ball of rock that you live on is called a planet. The name of this planet is Earth and it is pictured Spinning around Earth is another ball of rock which also floats in space. This ball of rock is called the Moon and can be seen as a bright white object in the sky at night. Sometimes it appears round and other times it is the same shape as a banana. Unlike Earth, nobody lives on the Moon. During the day, something else that you can see in the sky is a round bright yellow object. This is a ball of gas, light and heat much further away from Earth than the Moon is. The ball of gas, light and heat is a star. It is called the Sun. Your planet, Earth, spins around the Sun, taking 365 days to complete a journey around it.
Earth is not alone travelling around the Sun. There are another eight planets spinning around the Sun, four smaller than Earth and four bigger than it. Spinning around some of these other planets are more moons, some bigger than Earth's moon, and some a lot smaller. The Sun in the middle, the nine planets spinning around it, and the moons spinning around them make up what we call the Solar System.
The Solar System all sounds quite simple, doesn't it? But, when we look at it more closely, we realise that it is a lot more complicated than we first thought. The nine planets in the Solar System are all very different to each other. One planet has a pink sky and red surface, another has a wind storm that has been going on for hundreds of years. One planet has massive rings surrounding it, and if you stood on another, you would be crushed by the sky! Something else also unbelievable about the Solar System is its size. The Solar System is huge. The Sun itself is big enough to fit 109 Earths side-by-side in it. If a spaceship left Earth to go to the furthest planet away from the Sun, it would probably take 12 years to reach it. The Solar System itself is just one tiny part of space. The Sun is one of billions of stars. Other stars, many, many millions of miles away from Earth, only appear as bright dots in the night sky. Some of these stars are even bigger than the Sun, yet are so far away that they appear tiny. Even these have their own planets spinning around them.
.
* World population data is estimated in July 2005 as being 6,446,131,400 by the Central Intelligence Agency for the World Factbook. Internet link: http://www.cia.gov/cia/publications/factbook/rankorder/2119rank.html
| BACK TO INTRODUCTION | BACK TO TOP | NEXT STAGE |