Guide to Space
Space is an absolutely huge place. It's very dark, very large and very quiet. Our planet spins around the sun in space, and because there is no gravity, objects can float around without touching anything. Incredible, isn't it?
For centuries, scientists have argued about how space works. It is now known that the planet earth is a ball, like a football, and spins around a bigger ball known as the sun. The sun is a very, very hot ball of gas that emits heat and light. The heat and light is what makes the earth so warm, and so able to grow different kinds of life.
Imagine the sun as a beach ball and the earth as a football. The football is spinning around the beach ball, whilst spinning as well on its own axis. So when the ball turns on its own axis, there is a time where there is no light getting to one side of the earth. This is where night comes from!
Then if you can imagine there are a number of smaller bouncy balls spinning around the beach ball, but are much further away. This means that these planets are much colder, as they are further away from the sun.
What's amazing is, however, there are many more different systems like this! Throughout the whole of space, you will find many suns (or beach balls) which all have planets trailing around them.
And as it is thought that space is infinite, this means there is an absolutely huge number of planets out there - which could possibly contain life like planet earth does! Not only is space infinite, but it's ever expanding. When I first heard that I thought my brain was going to melt. How can anything that is too big to even put a number on it be getting bigger? It almost is beyond reason until you think about it deeply. Scientists know that the universe is getting bigger because when you study small areas they stretch out over time. It is kind of like those little critters you put in a glass of water as a kid. You walk in the morning and they were 50 times their size. If you knew the universe was made up of that stuff, then it had to be getting bigger every day.
So what does infinite mean? Well imagine you have two coins. Here you only have two coins, and no more. As soon as you've spent the two coins, they have gone.
Now imagine you have coins in your pocket. Every time you take a coin out of your pocket and pay for something, another one appears in your pocket - and you can spend that on something else.
Basically, 'infinite' means there is no end! Can you imagine that space is a large place, which is very dark, very cold and has no ground - and simply goes on forever and ever. Even before humans existed, space had been infinite. And even when we all die, space will exist and will have many thousands planets occupying the infinite (and growing!) amount of space.
In space, nobody can hear you talk either. This is because there is a 'vacuum'. A vacuum is a place whether there is no air. So whilst you can't breathe in space, the vibrations that you make when you shout cannot travel through the particles in the air. Because there are no particles! Sound waves can only travel through particles.
Space begins, technically, at about 200 kilometers above the earth. There is a kind of 'shell' around the planet, known as the atmosphere, that doesn't go any further than 200 km. Once you are past this there is less air and the blue sky turns into black, with many yellow dots which are stars.