Our World (Answers for Kids)
As far as we know, our sun's family of planets, moons, meteorites, and comets is the only one of its kind in the whole universe — and it is very special!
At the centre of our solar system is a star — we call it the sun — which provides power for all the other objects. The pull of the sun's gravity keeps the planets moving around it, and they keep time so perfectly that we can predict where each planet will be many years in the future. The sun's planets (beginning with the nearest) are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. There is also a band of rocky objects (called asteroids) between Mars and Jupiter, and other objects called meteorites, which sometimes fall to earth. Then there are comets which sometimes pass near earth.
How did our solar system begin? Many scientists believe it was born from a swirling cloud of gas and dust, and that over millions of years the bits of dust stuck together to become bigger and bigger until the planets were formed. But as no scientists were around to see how it began, this is only a guess. And it is not a very good guess either, because dust clouds do not tend to form into lumps. The real reason why people suggest such ideas is that they would rather not believe that our solar system was created by God.
When we look at the design of our solar system, it seems impossible to believe it was made by accident. And only one planet —Earth — is suitable for life. Mercury and Venus, which are much closer to the sun than we are, have temperatures much too hot, while those further from the sun are much too cold.
Some members of the sun's family
Saturn is a frozen giant. It has thousands of rings made of pieces of rock and dust. The Voyager 2 spacecraft revealed that Jupiter and Uranus also have ring systems.
Venus is about the size of earth, but is very hot, because it is so close to the sun. It is covered with clouds, and was once thought to be a wet planet. Now, spacecraft have sent back pictures which show that Venus is just like an oven!
Click on the image(warning large file, 120K) to see a full-sized illistration about exploring space
Tom and Jenny
Tom and Jenny's class were studying the solar system. They learned that the planets orbit the sun in the same plane as the earth, and are held in position by the gravitational pull of the sun. They heard that the sun is large enough to put a million earths inside, and has a surface temperature of 6,000 degrees Celsius.
'Wow! It must be hot on Mercury!', said Bob. 'We'd be fried!'
'Yes,' agreed Miss Wright, 'there is no atmosphere, either, so there could be no life.'
'Venus', she went on, 'appears to us as a bright morning or evening star. It does have an atmosphere, but you couldn't breathe it, for it contains droplets of hot sulphuric acid and carbon dioxide. And with a temperature of 460 degrees, there could be no liquid water.'
'I hope we don't move nearer the sun,' said Babs.
'Earth is moving at just the right speed to keep us about 150 million kilometres, or 93 million miles, from the sun,' explained Miss Wright. 'We take 365 days, 5 hours, 48 minutes, and 45 seconds to orbit the sun once. If we went slower we could get nearer and be burned up, but if we went faster we could move away and freeze. As it is, we have the right temperature, air to breathe, and liquid water.'
'Fancy our blood boiling or being frozen!' remarked Ralph, 'But don't some people think there's life on Mars?'
'They did, but the Mariner and Viking space probes found that Mars is a barren desert with awful dust storms. All the water is frozen, and the atmosphere is mostly carbon dioxide, which is no good for breathing.'
'And nothing could live on the planets further out, could it?' asked Babs.
'No. Jupiter has clouds of poisonous gases and oceans of liquid hydrogen. It has some thin rings around it and at least 16 moons, four of which orbit Jupiter the opposite way to the others.'
'So we can't go there,' commented Babs. 'I suppose Saturn is worse, even though its rings look beautiful?'
'Yes. Its atmosphere is mostly hydrogen and helium, and with a temperature of minus 180 degrees, it is cold enough to have liquid hydrogen. Saturn has 21 moons, and one of them, Titan, is actually larger than the planet Mercury.'
Miss Wright explained that the Voyager 2 spacecraft had passed by the planet Uranus in January 1986. 'It took photos of Uranus's five largest moons and found the planet also had thin, dark rings around it. Again, it has a poisonous atmosphere and the temperature is bitterly cold. Uranus is tilted at a strange angle of 98 degrees, compared to earth's 23° degrees. And Uranus takes 84 earth years to orbit the sun. No life there!'
'What about Neptune and Pluto?'
'Voyager 2 reached Neptune in June 1989, and has since passed Pluto and left the solar system. Neptune and Pluto are even colder than Uranus, and from tiny Pluto, at a distance of 5,900 million kilometres, or almost 3,700 million miles, the sun would only appear as a bright star.
'So we're lucky earth's speed, size, atmosphere, and distance from the sun are all just right,' said Miss Wright.
Tom put up his hand. 'Please, Miss Wright, I don't think it's luck. I think God arranged it exactly right for living things.'
'Well yes, Tom', Miss Wright said thoughtfully. 'So many things have to be exactly as they are, I think you must be right. That means we have to look after our planet home carefully, doesn't it?'
Weird and Wonderful
The Marvellous Moloch
Looking rather like a walking cactus, the moloch is a lizard which lives in the Australian deserts. It's not surprising that this strange creature is also called the thorny devil, for it has a horny covering with lots of sharp spikes over its body. Although the moloch is only about 16 centimetres (6 inches) long, its spikes make it look quite scary, and few animals will attack it. Yet it is harmless, moves very slowly, and when frightened hides its head between its front legs.
The moloch's main food is ants, which it eats with its sticky tongue, sometimes polishing off thousands of ants in a single meal. In mid-summer, the female moloch digs a tunnel in which she lays about eight eggs, and the baby molochs are quite large — six centimetres long when they hatch.
The spikes on the moloch's body, which make it look so unusual, are there for a good reason. In the desert there is very little water, but during the cool nights dew collects on the lizard's skin. All over the moloch's body are tiny grooves which lead to its lips. This means it is able to quench its thirst by drinking the dew which collects on its spiky body!
It seems hard to believe that the moloch could have got its spiky coat and system of grooves through gradual evolution ... the spikes and grooves need to work together to give the moloch a drink. This strange, prickly lizard is perfectly designed for living in the desert — another of God's weird and wonderful creatures!
God loves our little speck!
Our solar system seems very big. The distance from the sun to the furthest planet, Pluto, is around 5,900 million kilometres, or almost 3,700 million miles. Yet compared with the whole universe, this is tiny! Our solar system is part of the Milky Way galaxy, which may have as many as 250,000 million stars in it — many much bigger than our sun.
So our planet, earth, seems like a tiny speck among the many billions of stars and galaxies in our vast universe. This may make us feel that our world is not important, but of course it is, because we live here! No other planet we know of is suitable for life, but everything on earth is just right for us. This could not have happened by accident, but points to a Creator who designed and planned it that way. This world was meant to be our home. Really, it is God's world, and we should thank Him for providing it for us to live in.
The world was perfect when God created it, but it was spoilt when the first people did wrong things, which brought death and suffering into the world. Wrong things separate us all from God. But the Bible tells us that God not only designed the world, He actually loves the world and its people. God proved it by coming to us in Jesus Christ, His Son. We all deserve to die for our sins, but Jesus died on the cross to pay for our sins, and rose again to enable us to live for ever with Him. God loved the world so much that He gave His only Son. God gave His Son so that whoever believes in Him may not be lost, but have eternal life (John 3:16). Our world may be a tiny speck, but God loves it. And you can know this love for you by accepting Jesus as your Saviour.