The surface of the Sun, known as the photosphere, is the layer that emits visible light. It has a temperature of about 5,500 degrees Celsius (9,932 degrees Fahrenheit) and appears as a bright, glowing sphere. The photosphere is not solid; instead, it consists of hot plasma, which is a state of matter made up of charged particles. Above the photosphere lies the Sun's atmosphere, which includes the chromosphere and the corona. The chromosphere is a thin layer that can be seen during a solar eclipse, while the corona is the outermost layer, extending millions of kilometers into space. The corona is much hotter than the photosphere, reaching temperatures of over 1 million degrees Celsius (1.8 million degrees Fahrenheit).