1. The mass of the Sun is about 2x1030 kg. The Sun was about 72% hydrogen when it first formed. About 11% of the total amount of the Sun's hydrogen is available for fusion within the Sun's core. [3 points] (a) What is the total mass of hydrogen available for fusion, in kg? (b) The Sun fuses about 600 billion kg of hydrogen each second. Calculate how long the Sun's initial supply of hydrogen can last. Give your answer in both seconds and years. Hint: use the result you calculated in part (a). (c) We know that our Solar System is about 4.5 billion years old. Using your calculation above, how much longer do we have until the Sun runs out of hydrogen?

1. The mass of the Sun is about 2x1030 kg. The Sun was about 72% hydrogen when it first formed. About 11% of the total amount of the Sun's hydrogen is available for fusion within the Sun's core. [3 points] (a) What is the total mass of hydrogen available for fusion, in kg? (b) The Sun fuses about 600 billion kg of hydrogen each second. Calculate how long the Sun's initial supply of hydrogen can last. Give your answer in both seconds and years. Hint: use the result you calculated in part (a). (c) We know that our Solar System is about 4.5 billion years old. Using your calculation above, how much longer do we have until the Sun runs out of hydrogen?