1. Assuming that the current rate of hydrogen fusion in the Sun remains constant, what fraction of the Sun’s mass will be converted into helium over the next five billion years? How will this affect...

1. Assuming that the current rate of hydrogen fusion in the Sun remains constant, what fraction of the Sun’s mass will be converted into helium over the next five billion years? How will this affect the chemical composition of the Sun?

2. What is a neutrino, and why are astronomers so interested in detecting neutrinos from the Sun?