Dictionary
sun
The central (and most massive) body of our solar system; the star closest to us; a ball of gas with a radius of ca. 700000 km (for comparison the radius of the earth: 12756 km) and a mass of 1.989·1030 kilograms [see exponential notation].
In the interior of the sun, nuclear fusion processes run their course; they are responsible for the sun’s impressive brightness.