Sun’s Energy Source Sun’s Luminosity _____ = 3.9 x 10 26 watts [Note: 1 watt = ______ ]

1. Sun’s Energy Source Sun’s Luminosity _____ = 3.9 x 1026 watts [Note: 1 watt = ______ ] Average power consumption by humans on Earth = ____________ Amount of sunlight reaching the Earth = ____________ [ _____________________________ ] Sun’s Energy Source Nuclear fusion Net: _____________ [ _______________ ] 4 H atoms = _______________ 1 He atom = _______________ Mass Lost = _______________

2. E = mc2 Example 1.000 kg H  _______ kg He [ Efficiency = ______ ] E = mc2 = ( _________ )( _____________ )2 = ____________ This amount of energy is equivalent to burning ____________ of coal !! To generate 3.9 x 1026 W  _____________ of H are converted to He every second. This also means that the Sun is losing ___________ of mass every second which is transformed to energy (i.e. ____________________ ________)

3. Fun Sun Facts: • The Sun is so large that ________ Earth’s could fit inside. • The Sun contains almost _______ of all the mass in the solar system. • The Sun’s lifetime on the main sequence is _________ years. • The Sun is ________________ old now. • Out of the 50 closest stars, the Sun ranks ____ in mass. Most stars are ___________ than the Sun. • The Sun’s nearest neighbor is ____________________ • _____. • The Sun is ______________________ than when it was first born.