1 Our Sun is about five billion years old and accounts for 99Our Sun is about five billion years old and accounts for 99.9% of the total mass of this solar system. Most scientists are optimistic that we'll still have a functional sun billions of years from now. DIAMETER:                                1,390,OOOkmREA:                         MASS:                                         1.99 trillion, trillion, billion kg     SURFACE TEMPERA:                5,800 K  CORE TEMPERATURE:             15,600,000 K ENERGY OUTPUT:                    386 billion, billion mega Watts/second POWER LEVEL AT EARTH:      1.4 kilo watts / sq meter