George's Secret Key To The Universe

'Why is it glowing?' asked George.

'The more it shrinks,' said Eric, 'the hotter it gets. The hotter it gets, the brighter it shines. Very soon it's going to get too hot.' He grabbed a couple of pairs of strange sunglasses from a pile of junk on the floor.

'Wear these,' he told George, putting on a pair himself. 'It will soon be too bright for you to look at without glasses.'

Just as George put on the very dark glasses, the ball exploded from the inside, throwing off its outer layers of burning hot gas in all directions. After the explosion, the ball was shining like the Sun.

'Wow!' said George. 'Is that the Sun?'

'It could be,' Eric replied. 'That's how stars are born and the Sun is a star. When a huge amount of gas and dust combines and shrinks to become dense and hot, as you've just seen, the particles in the middle of the ball are so pressed together they start to fuse or join up, releasing an enormous amount of energy. This is called a nuclear fusion reaction. It is so powerful that when it starts, it throws off the outer layers of the ball, and the rest is transformed into a star. That's what you just saw.'

The star was now shining steadily in the distance. It was a beautiful sight. Without the special sunglasses they wouldn't have been able to see much as the star was so bright.

George gazed at it, amazed by its power. Every now and then he could see huge jets of brightly shining gases sent hundreds of thousands of miles from the surface at extraordinary speeds.

'And the star will keep on shining like this for ever?' he asked.

'Nothing is for ever, George,' said Eric. 'If stars shone for ever, we wouldn't be here. Inside their bellies, stars transform small particles into larger ones. That is what a nuclear fusion reaction does: it fuses small particles together, and builds big atoms out of small ones. The energy released by this fusion is enormous and that's what makes stars shine. Almost all the elements that you and I are made of were built inside stars that existed long before the Earth. So you could say that we are all the children of stars! When they exploded, a long time ago, these stars sent into outer space all these large atoms they created. The same will happen to the star you are looking at now, behind the window. It will explode at the end of its life, when there are no more small particles available to fuse into bigger ones. The explosion will send into outer space all the large atoms the star created in its belly.'