Scientist used to believe that chemical reactions fueled the Sun. Why did this lead them to believe that the sun was very young? What kind of reactions do we now think are responsible for the energy released by the sun. In one to two sentences, explain your reasoning.

Answer 1

Scientists used to believe that chemical reactions fueled the Sun because they thought the Sun was composed primarily of elements like hydrogen and carbon. Since chemical reactions would have depleted the Sun's fuel quickly, they inferred a young age. However, we now understand that nuclear fusion reactions, specifically the fusion of hydrogen nuclei into helium, release the energy in the Sun, allowing it to sustain its energy production for billions of years.