The Sun's Core Is About 27 Million Degrees Fahrenheit

The Sun is hottest at its center. NASA states that the temperature in the Sun’s core is about 27 million degrees Fahrenheit, or 15 million degrees Celsius, which is hot enough to sustain nuclear fusion. Fusion there creates outward pressure that supports the star’s gigantic mass and keeps it from collapsing. The core is enormous in its own right, about 86,000 miles, or 138,000 kilometers, thick. Temperatures change sharply as you move outward. The part of the Sun we call its surface, the photosphere, is a relatively cool 10,000 degrees Fahrenheit. Then, oddly, it gets hotter again. NASA says the corona, the Sun’s expansive outer atmosphere, reaches up to 3.5 million degrees Fahrenheit, much hotter than the photosphere below it. For all that, NASA calls the Sun only an average star in terms of size.