It’s officially summer! Here are FUN FACTS about the SUN. 5,700°C – The estimated temperature of the sun’s surface 75% – The amount of the sun composed of HYDROGEN. The rest is mostly HELIUM. 2×1027 TONS – The mass of the sun (approximate equivalent to the weight of 333,000 Earths) 150 million km – The distance from the Earth to the sun 15,000,000°C – The estimated temperature of the sun’s core 250 million – The number of years it takes for the sun to orbit our galaxy 4.5 billion years – The age of the sun fun fact Sunlight does not contain vitamin D. Rather, exposure to UV light stimulates the synthesis of Vitamin D in our skin.