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| | Cosmic Evolution - Epoch 3 - Stellar Evolution |
 | | Hydrostatic equilibrium—as in a “compressible fluid,”; which is the way stars are modeled—tends to stabilize a star at every point within the star, to keep it from collapsing or exploding, in either case catastrophically. |
 | | Note also, to make another clarification, that even in hydrostatic equilibrium, a star like the Sun continues to change its luminosity—that is, its rate of energy flow—ever so slightly over the course of its lifetime. |
 | | This small expansive adjustment of the core halts the gravitational contraction of the star, reestablishing an equilibrium of sorts—in this case, a balance occurring at the quantum level among the densely packed electrons whose tiny point-like spheres are essentially touching one another, thereby physically holding up the aged star against gravity. |
| www.tufts.edu /as/wright_center/cosmic_evolution/docs/text/text_stel_4.html (5502 words) |
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