Question

Are energy and matter both conserved into stars?

Answer 1

Yes, both energy and matter are conserved in stars, although the forms they take can change during the processes that occur within a star.

1. **Energy Conservation**: In terms of energy, stars generate energy through nuclear fusion, primarily converting hydrogen into helium in their cores. This process releases a significant amount of energy in the form of light and heat. The total energy in the system (the star) remains constant according to the law of conservation of energy. Energy can be transformed from one form to another (e.g., from mass to energy during fusion), but it is neither created nor destroyed.

2. **Matter Conservation**: Matter is also conserved, although it can change form. In the process of fusion, hydrogen nuclei (protons) fuse to form helium nuclei, but the total mass-energy of the star remains the same. In some cases, the mass of the resulting helium is slightly less than the mass of the original hydrogen, and this "lost" mass is converted into energy (as described by Einstein's equation, E=mc²). However, the overall matter, including the new particles formed during various nuclear reactions, is conserved in a broader sense when considering the entire system's mass-energy.

In more complex interactions, such as in supernovae or neutron star formation, the conservation laws still apply, but they manifest in different ways, with important implications for the evolution of stars and the universe as a whole.