FAST FACTS ABOUT THE SUN:
Location: outer edge of a spiral arm of the Milky Way
Diameter: 1.39 million km
Mass: 1,989,000,000,000,000,000, 000,000,000,000 kg
Age: ~4.5 billion years
Life expectancy: ~5 billion years
Structure (from inside to out): core, interior, convection zone, photosphere, chromosphere, corona
Composition: hydrogen > helium >> oxygen, carbon, nitrogen, silicon, magnesium, neon, iron, sulfur > at least 57 other elements
Solar cycle (sunspots): average duration 11 years
Number of sunspots per year: almost none to as many as 100-200
Source of energy: nuclear fusion (hydrogen to helium)
Temperature: core ~15.6 million K, photosphere ~5800 K, sunspots ~3800 K, corona > 1 million K
