The Universe - The Sun

The Sun is by far the biggest object in the Solar System.



The Sun makes energy by a process called nuclear fusion.

Hydrogen atoms in the centre are under great pressure and temperature.

When they combine to make helium they release energy.
It is often claimed that the Sun is causing global climate change.

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What is the worst-case scenario for climate change? The geological record shows that when the atmosphere suddenly changes, there are big effects on living things. Five major  mass extinction  events are recorded in the rock record of the last 600 million years. The biggest extinction was at the end of the  Permian , around 252 million years ago. It is called the  End-Permian mass extinction. Only about 8% of species survived to live on in the Triassic Period. This photo shows geologists investigating tilted sedimentary rocks at Shangsi in South China. Triassic rocks (at the top right) lie over the older Permian rocks. Each mass extinction in the rocks matches with a change in the chemistry of the rocks called a ' carbon excursion '. Some of the carbon excursions are 'negative CEs' and some are 'positive CEs'. Negative CEs  indicate that lots of gaseous carbon compounds escaped into the air, causing warming. These are sometime
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Climate Change - The Greenhouse Effect

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Climate Change - Coal and carbon dioxide

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