Final answer:
No, the Sun cannot use coal as an energy source to emit as much energy as it does through nuclear fusion. Coal and other chemical fuels don't produce nearly enough energy and wouldn't even survive at the Sun's high temperatures.
Step-by-step explanation:
The question joins on whether the Sun could use coal as an energy source to produce its immense energy output in the same amount of time as it currently does through nuclear fusion. The answer is No. Coal, wood, gasoline, and similar materials undergo chemical reactions such as oxidation (commonly referred to as burning) to release energy. However, these chemical energy sources are not nearly sufficient enough to match the energy the Sun emits. If the Sun were to rely on coal as an energy source, it could only produce its current level of energy for a few thousand years at most, which is far less than the geologic evidence pointing to a Sun shining for at least 4 billion years. Furthermore, given the high temperatures on the Sun, physical materials like wood or coal would not even be able to exist in a solid state.