Timeline for Why doesn't matter clump together such that it can't be taken apart again?
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5 events
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| Feb 23, 2015 at 16:10 | comment | added | orion | The the "width" of the probability distribution is limited by the fact that the wavefunction must solve the Schrödinger equation (which can roughly be translated into the trade-off between mean square radius and mean square momentum, aka, the uncertainty principle). The Pauli exclusion principle prevents collapse of all electrons into the same lowest orbital, but for a single electron, you don't need the Pauli principle to derive the Bohr radius. That's all because if you squeeze the wavefunction, you increase its energy. | |
| Feb 23, 2015 at 15:28 | comment | added | ACuriousMind♦ | @orion: Why would it be the uncertainty principle that prevents the collapse of atoms? It is simply the discretization of allowed states and the Pauli exclusion principle that prohibits the electrons from "falling into the nucleus", and instead makes them from nice shells. | |
| Feb 23, 2015 at 8:51 | comment | added | orion | Also, the distance on which gravity would become comparable to the EM force (and strong and weak too) for elementary particles (the Planck scale), is much shorter than any reasonable microscopic scale. So other forces will prevent the collapse long before gravity is felt at all. Of course, the uncertainty principle prevents a collapse as soon as the force becomes relevant (that's why atoms are stable). | |
| Feb 22, 2015 at 0:46 | vote | accept | Ms. Molly Stewart-Gallus | ||
| Feb 22, 2015 at 0:18 | history | answered | ACuriousMind♦ | CC BY-SA 3.0 |