Electron degeneracy

[alokmohan]

Electron degeneracy issomewhat like human clautrophobia.When matter is squeezed to a density 10000 times higher than rock,the cloud of electrons aruond each of its atomic nuclei gets squashed 10000 fold.Each electronthereby gets confined to a cell with 10000times smaller volume than the one it previously was allowedto move around in.With so little spce available to it ,the electron ,like a claustrophobic human,starts to shake uncontroably.It flies about its tiny cell at high speed, kicking with great force against adjacent electrons in their cells. This 'degenerate motion', as physicists call it, can not be stopped by cooling the matter. Nothing can stop it; it is forced on the electron by the laws of quantum mechanics, even when the matter is at absolute zero temperature.<br /><br />This degenerate motion is a feature of matter that Newtonian physicists never dreamed of ,a feature called wave/particle duality:every kind of particle ,according to quantum mechanis ,sometimes behave like a wave ,and every type of wave sometimes behave like a partcle.Thus waves and particles are really the same thing,"a thing" that somtimes behave like a wave and sometimes behave like a particle.

 

[alokmohan]

AND THIS IS MOST RELEVANT WHEN WE TALK OF WHITE DWARF UPWARDS.

 

[Saiph]

umm...is that quote of something? It doesn't quite sound like your normal style. <br /><br />Also...is this supposed to be a reply to something? Cause it seems a bit odd as a thread starter. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[mikeemmert]

I have an interest in electron degeneracy in regards to brown dwarfs. I wonder if alokmohan is answering me and can't find the thread? I don't remember which one either. alokmohan?

 

[Saiph]

brown dwarfs don't have the mass to initiate core hydrogen fusion, let alone create any electron degeneracy<br /> <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[alokmohan]

Alokmohan has managed to get copy of Kip Thornes book on black hole and wanted to see reaction of SDC members .He has started serial on electron degeneracy.You get more.

 

[alokmohan]

Electron degeneracy is easily understood in terms of wave/partile duality.When matter is compressed to high densities,and each electron inside the matter gets confined to an extremely small cell sqeezed up against neighbouring electron cells,the electron begins to behave in part like a wave.The wave length of the electron wave(the distance between its crests)cannot be larger than the elecrons cell,if it were ,the wave would extend beyond the electron cell.Now particles with short wave length are necessarily highly energetic. Like xrays. In the case of an electron inside a very dense matter ,the electrons short wave length and accompaning high energy imply rapid motion,and this means that the electron must fly around its cell,behaving like an erratic ,high speed mutant:half particle and half wave.Physicists say that the electron is degenerate and they call the pressure that its erratic high speed motion produces "electron degeneracy pressure"

 

[mikeemmert]

<blockquote><font class="small">In reply to:</font><hr /><p>You get more.<p><hr /></p></p></blockquote>Thanks, keep it coming <img src="/images/icons/laugh.gif" /> .

 

[mikeemmert]

You can have electron degeneracy without fusion, and vice-versa. White dwarfs are electron-degenerate but there is no fusion. Red dwarfs are convective throughout, so I don't think there is any electron degeneracy...of course, that might just be me "thinking" (<img src="/images/icons/crazy.gif" />) .<br /><br />I hope alokmohan can clear up some of my ignorance. I welcome these posts.<br /><br />

 

[Saiph]

Oh, I know you can have electron degeneracy without fusion. However, you can't get to a stage that has electron degeneracy (in nature anyway) without being able to undergo fusion.<br /><br />A brown dwarf doesn't have the pressure to start hydrogen fusion, let alone create the conditions for electron degeneracy. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[alokmohan]

THEMAL PRESSURE ABSENT IN BROWN DWARF.

 

[mikeemmert]

Thank you, alokmohan. Question for Saiph; if there's no thermal pressure, why doesn't a brown dwarf collapse into neutronium or strange matter or a black hole or something?<br /><br />"Brown dwarfs<font color="yellow"> occupy the mass range between that of the lowest mass stars (anywhere between 75[1] and 80 Jupiter masses) and large gas-giant planets. Currently there is a large ambiguity as to what separates a brown dwarf from a giant planet at very low brown dwarf masses (~12 Jupiter masses). There is some question as to whether brown dwarfs are required to have experienced fusion at some point in their history; in any event, brown dwarfs heavier than 13 Jupiter masses (MJ) do fuse deuterium and above roughly 65 MJ fuse both deuterium and lithium<font color="white">".<br /><br />I have read the same thing in a variety of sources, including Scientific American, Sky and Telescope, and Astronomy magazines. The deuterium and lithium fuels don't last very long, both because there isn't much of it and because it burns fast. After that, I don't see what would keep them from collapsing except electron degeneracy pressure.<br /><br />I wish I knew more about electron degeneracy pressure. How did <i>I</i> ever get into this debate, anyway? <br /></font></font>

 

[yevaud]

Remember, a Neutron Star is created when the mass of the body is past the Chandresekhar Limit (1.44 Solar Masses). Brown Dwarfs are intermediate objects, between Superplanets and full Stars.<br /><br />General Information on Brown Dwarfs<br /><br />ArviX Abstract <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[Saiph]

no thermal pressure? Really? That's a neat trick. The only time thermal pressure isn't an issue is in degenerate states IIRC.<br /><br /><br />Brown dwarfs are sustained by the same mechanisms that keep jupiter from collapsing. Standard electrostatic repulsion, and thermal collisions (i.e. random collisions of moving atoms). <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[alokmohan]

Mike, it collapses due to gravity.Why you require electron degeneracy.Thats the reason brown dwarfs dont collapse into white dwarf and kin.When collapse is due to degenaracy the body becomes very small.

 

[alokmohan]

IIRC?Of course you are right in pointing my mistake.

 

[mikeemmert]

Dear Yevaud;<br /><br />Thank you for your posts concerning liquid metallic hydrogen. What I am wondering is what the difference between pressure ionized liquid metallic hydrogen and degenerate matter is.<br /><br />Pressure ionized liquid metallic hydrogen has been achieved in the laboratory with difficult and heroic techniques. Therefore, it can be studied. I read about this in the print press at the library, and you know why I was hanging out at the library, so I don't have a link. Sorry.<br /><br />My understanding is that metallic hydrogen is a liquid with low viscosity which flows easily. Degenerate matter, on the other hand, is a crystal in which the material is not free to move. There is a phase change between the two, which liberates heat energy, much like when water freezes into ice.<br /><br />These states of matter are normal in the Universe at large, but highly unusual in Earth laboratories. We're going to be stuck with theories on this for a long time. Better theories than total ignorance.

 

[alokmohan]

Degenerate matter is unlike anything we see in the earth labs.On the other hand we start with degenerate matter to know big stars.For long astrophysicists had computed the details of the balance of gravity and pressure inside a star whose matter had a resistance to compression that is independent of depth of the star:a star whose pressure and density incrase in step with each other,as one moves deeper and deeper in the star,with 1 percent increase in density always accompaied by the same fixed percent increase in pressure.All these studies were done by Arthur Eddington.His book ,the internal constituon of star.Later on Chandrashekar India American astrophysict calculated the speed of electrons in white dwarf stars move at 57 pecent of speed of light.,relativistic in nature...You may appreciate this has no similarity to pressure in ionized liquid metallic hydrogen.