If the CNO process is allegedly more efficient, does that mean a star with a higher mass might live longer than a smaller one that mainly use proton-proton fusion? Or is it even worse for the lifetime of a star?
See eg. https://websites.pmc.ucsc.edu/~glatz/astr_112/lectures/notes... for a more detailed explanation.
Using some hand-wavy arguments you could say that fusion pauses a star's collapse, so the more massive a star is, the more energy generation it needs to stay in equilibrium during this pause.
Therefore, the rate of energy production isn't a consequence of the temperature. The rate of energy production is regulated, so effectively the temperature is a consequence of the required energy production instead.
The solar sunspot cycle is caused by the periodic inversion of the polarity of the sun's magnetic field.
Would that mean that massive first generation stars could live longer than their current brethren, since there wasn't any C, N, or O yet?
Notice that haiguise wrote "at the core temperature of the Sun." A more massive star has a higher core temperature, and thus haiguise's sentence about fusion rates would no longer apply. Fusion rates are faster at higher temperatures, and that's why more massive stars burn out faster. Notice haiguise wrote "T^4" and "T^20." Our sun is roughly 5000K. Massive stars can exceed 10000K. At twice the temperature, T^4 and T^20 imply 16x and 1,048,576x fusion rates, respectively.
Edited to add: Wikipedia has an HR diagram with labels showing lifespans for stars at different temperatures: https://commons.wikimedia.org/wiki/File:Hertzsprung-Russel_S....
If fusion creates the potential for fission (radioactive waste) and radioactive waste can be used to build atomic bombs, how have we not figured out how to make mini perpetual-energy reactors?
It's possible to create hypothetical situations where all of the must fundamental laws are being followed but the second law of thermodynamics is violated (for example if there are many more 'ordered' states than 'disordered' ones). And there is some vanishingly small chance that it will be violated in our universe for a macroscopically observable length of time.
In practice you won't go wrong by treating it as absolute.
e.g. if new voxels of spacetime are created during, and they contain zero-point energy... may account for photons losing energy as they red shift over large distances.
See this graph: https://opentextbc.ca/universityphysicsv3openstax/wp-content...
So it’s not a perpetual motion machine. Iron is the bottom.
(Heavier stuff than iron can be created by fusion, but that absorbs energy instead of releasing it. Supernova create these heavier-than-iron elements like Uranium and gold endothermically... they’re also created by the decaying guts of neutron stars—which are essentially ginormous atomic nuclei held together by gravity instead of nuclear forces—when they collide and some of their guts are released into space.)
I'm not sure if endothermic is the best word. IANAP. It seems to usually be used when discussing fusion-based neutron generation. But AFAICT neutron generation, especially as it relates to the s-process, is still largely a thermal process--the greater the temperature, the more neutrons are generated, the faster the s-process evolves. (If you go back to the beginning of the universe all nuclear synthesis represents an endothermic process, right? Though, maybe such semantic games aren't particularly helpful when distinguishing nuclear synthesis processes.)
I'm afraid you're quite off base here.