Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/26/83; site ihuxm.UUCP Path: utzoo!linus!philabs!cmcl2!floyd!whuxlb!pyuxll!eisx!npoiv!npois!hogpc!houxm!hocda!spanky!burl!we13!ihnp4!ihuxm!cmsj From: cmsj@ihuxm.UUCP Newsgroups: net.physics Subject: Re: opposites attract Message-ID: <360@ihuxm.UUCP> Date: Wed, 13-Jul-83 09:46:16 EDT Article-I.D.: ihuxm.360 Posted: Wed Jul 13 09:46:16 1983 Date-Received: Thu, 14-Jul-83 21:31:18 EDT References: <2075@tekmdp.UUCP> Organization: BTL Naperville, Il. Lines: 32 There are two parts to Roger's question and I'll try to answer them: First, why don't the electrons fall into the nucleus? One of the simplest ways of "explaining" this is via the Heisenberg Uncertainty Principle (which comes out of Quantum Mechanics). The principle states: delta_p * delta_x >= h/2*pi where delta_p is the uncertainty in a particle's momentum and delta_x is the uncertainty in its' position. h is Planck's constant. Basically this inequality states that it is not possible to know both the position and momentum of any particle simultaneously to arbitrary precision. Appllying this relation to an electron confined to nuclear (not atomic) dimensions ( nuclear radii are roughly proportional to A ** (1/3) where A is the atomic weight; the units of the radii are in Fermi (1 F = 10 ** (-15) meters)) results in an electron energy which is WAY too high for the electron to remain where it is. Hence no electrons in the nucleus. The second question, how do protons stay together in the nucleus? Well, it is true that protons repel each other via the electromagnetic force. However, at close enough range, another force (suitably named the "strong" interaction) takes over and this force attracts the protons (and neutrons) to each other. Hope I remembered enough of my Physics... Chris Jachcinski BTL, Naperville, IL ..!ihnp4!ihuxm!cmsj