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The Sun (continuation)

The hottest part of the Sun is its core, where temperatures top 15 million degree

Celsius. The surface of the sun is called the photosphere. It is a relatively cool

5,500 degree Celsius. In one of the Sun’s biggest mysteries, the Sun’s outer

atmosphere, the corona, gets hotter the farther it stretches from the surface. The

corona reaches up to 2 million degree Celsius which is much, much hotter than

the photosphere.