nuclear fusion in a star 's core generates energy for stars to burn / shine
sun is giant_fusion_reactor. star is not burning_in_space. fusion_rocket is not nuclear_rocket. star is burning_ball_of_gas. star is burning_in_space. dense_blazing_star is blazing_star. stars is balls_of_burning_gas. stars is not balls_of_burning_gas. fusion_rocket is nuclear_rocket. sun is not giant_fusion_reactor.