stars cheat physics to shine, sneaking protons past a wall they have no business crossing.
means a nuclear fusion process where particles fuse despite lacking the classical energy to overcome their mutual repulsion, because quantum mechanics lets them borrow a little probability instead.
from in the 1920s, george gamow realized stellar cores were too cool for protons to smash together by brute force alone, so he applied the new quantum theory of tunneling to explain how fusion happens anyway, work that let eddington's stellar models finally add up.
the sun — proton-proton chain fuses 600 million tons of hydrogen per second via tunneling
red giants — helium fusion ignites through tunneling at hotter, denser cores
early universe stars — population iii stars relied on tunneling to fuse near-pure hydrogen