The Sun didn't exist 15 billion years ago. It is 150 million km away from the earth and is a star.
The sun has 5 layers, the first layer in the inside is called the heart which has nuclear reactions, then comes the photosphere which is 300 km thick and is the layer that gives us light. the third layer is the chromosphere it's very thin and is visible during an eclipse. Then there is a thin ring that scatters the light that comes from the photosphere. And the last layer is sunspots, they have the lowest temperature, and the sunspots explode every couple of days or up to a week. When the sunspots explode they shoot out gas that can reach up to 500 0000 km of height.
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