In a book* I was reading, it said that a neutron star is formed when the pressure is so large that the electrons in a white dwarf interact with the protons, forming neutrons. The neutrons then collapse until the Pauli Exclusion Principle stops any further collapse.  However, my issue is with why, when the mass is even greater, how the neutron star collapses into a black hole:  The book says that the pressure is so high, and therefore the temperature is so high, that the neutrons start to move close to the speed of light. At this speed, the Pauli Exclusion Principle doesn't apply any more and the neutron star goes on to implode.  Why does the Exclusion Principle stop working at high speeds?  * The book was  by Brian Cox and Jeff Forshaw. The subject of this question can be found in the chapter Epilogue: The Death of Stars
From  (emphasis mine):     Neutron degeneracy is a stellar application of the Pauli Exclusion Principle, as is electron degeneracy. No two neutrons can occupy identical states, even under the pressure of a collapsing star of several solar masses. For stellar masses less than about 1.44 solar masses (the Chandrasekhar limit), the energy from the gravitational collapse is not sufficient to produce the neutrons of a neutron star, so the collapse is halted by electron degeneracy to form white dwarfs. Above 1.44 solar masses, enough energy is available from the gravitational collapse to force the combination of electrons and protons to form neutrons. As the star contracts further, all the lowest neutron energy levels are filled and the neutrons are forced into higher and higher energy levels, filling the lowest unoccupied energy levels. This creates an effective pressure which prevents further gravitational collapse, forming a neutron star. However, for masses greater than 2 to 3 solar masses, even neutron degeneracy can't prevent further collapse and it continues toward the black hole state.   How then, can they collapse, without violating the Pauli Exclusion Principle? At a certain point does it no longer apply?
Has anyone successfully deleted the Windows Installer files successfully before? They are taking up 35.1% of my total hard drive space.  Which ones are needed and which ones can be purged?  In order to see this folder, I had to unhide system files by going to Windows Explorer > Organize (dropdown) > Folder and Search Options > view tab > uncheck ==> Hide protected operating system files (Recommended).  I used WinDirStat program to get these percentages. To see the image in full size, open it in a new tab.  I was told by someone that you should not delete these files, but then I found a utility--Windows Installer CleanUp Utility (very old version) that deleted these.  But it doesn't run on Windows 7.  If anyone has a later version that they found works, please let me know the path. Old Budrys(?) end-of-world/alien invasion of NYC story This one, from the late 1950s or early 60s (I think), features the last girl in NYC, who drives her jeep up the stairs of the main library (with the lions). She feels bad about breaking the lock, but what's a girl to do, if she wants something to read? In summertime, she drives topless and, the author writes, her bosom dances enchantingly on the steps. She lives in the boathouse on the lake in Central Park. Mysterious insect-like aliens are eating the buildings in the City.... I didn't recognize a title in Budrys or Bester's isfdb bibliogs, so I may be wrong about the author. But not about the story details: it's a memorable one. Thanks in advance for helping ID this one! Can't use String#trim as a callback for Array#map Why every map $f : S^n \to T^n (n>1)$ has topological degree zero? Why every map $f : S^n \to T^n (n&gt;1)$ has topological degree zero?  I don't know anything about covering spaces, and has been told to me that this assertion comes from this theory!  I do appreciate any help. One-dimensional vector space and it's subspaces Prove there are no other solutions of functional equation $f(x+y) = \frac{f(x)+f(y)}{1-f(x)f(y)}$ How to find real world Selenium projects Where can I find sample or real Selenium projects. All the material I can find on github and on internet are basic, and never intermediate or advanced.  How does a real Selenium project look in real life? How can I find sample code? Proving $\lim_{n\to\infty} a^{\frac{1}{n}}=1$ by definition of limit I noticed that sometimes my code gets highlighted in different colors when rendered.   What is syntax highlighting? How does it work? Why isn't my code being highlighted correctly? How do I report a bug or request a new language? How do I use syntax highlighting? What languages are currently available on Stack Exchange? My question was closed for being a "shopping list question", even though it was very much related to the topic of the site. Why? How to install KDE along Unity? I have just installed the latest Ubuntu 14.04 and I would like to install KDE along side my Gnome/Unity that I have now. How can I do this?  Thanks! I wrote an algorithm to randomly generate terrain and I am trying to load and edit my results with blender.  The problem is that when I load my terrain in blender, the individual triangles are not linked together.     You can see when I shrink/flatten a subset the the faces, the rest don't follow and deform as a single mesh.  I tried deleting the faces and edges and using F to create faces from the points, but it does not give usable results.    How can I go about solving this problem? Why shouldn't root be allowed to login via ssh? why should root access be disabled for ssh? I always hear that's for security reasons. But I don't get it. What's different to login as non-root and then sudo su -? What's the preferred way to handle tasks that need privileged permissions?  Thanks  Thomas Discount for Roles I am using Drupal Commerce and I would like to know if it is possible to have discounted prices for registered users and much better for roles.  For example, the nomral price is $100 but when a user logs in that belongs to Role1 for example, he will see different prices with the percentage discount that I will have assigned to that role.  How can I accomplish such a feature? How do I remove objects from an array in Java? The following is an Exercise of Conway's Functional Analysis.   Prove that $X$ is a $\,Banach$ space iff whenever $\{x_n\}$ is a sequence in $X$, such that $\sum \| x_n \| &lt; \infty$, then $\sum x_n$ converges.   I easily can show that if $X$ is a Banach space then $\sum x_n$ converges. My problem is showing that $X$ is a Banach space. For this I suppose that $\{s_n\}$ is a Cauchy sequence in $X$, then I want to make a series. For this I do not have any idea. Please help me. Support for OpenID ended on July 25, 2018 NOTE: Signing up or Logging in via OpenID is no longer officially supported from any of our sites. Currently,  is still on the internet, but we are in the process of completely removing it.    Stack Overflow was an early and strong supporter of . We built our sign up/log in flow around it. We were idealistic and had , but these hopes weren't realized. Over the years people have wondered if  is . We've had to remove support as OpenID providers  or .  The time has come to part ways. The reality is OpenID support has created a ton of complexity in our codebase and the number of users actively using OpenID simply don't justify that cost. Users have spoken with their actions. You prefer Google, Facebook and Stack Exchange (aka email/PW) based account auth.     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Obviously, if your account relies on OpenID, then make life easy and go now and .   If you've forgotten what you credentials you use to login, then  to refresh your memory. If you don't see one of the three account types shown in the image below (Google, Facebook or Stack Exchange) then click the "add more logins" button to add one of them to your account.    Remember, SE OpenID accounts are really email/pw accounts handled through complicated OpenID code path. They will be migrated to a simpler email/pw only code path as a part of this change. No extra work required on your part. Why does HTML require that multiple spaces show up as a single space in the browser? I have long recognized that any set of whitespace in an HTML file will only be displayed as a single space.  For instance, this:  &lt;p&gt;Hello.        Hello. Hello. Hello.                       Hello.&lt;/p&gt;   displays as:  Hello.        Hello. Hello. Hello.                       Hello.  This is perfectly fine, as if you need multiple spaces of pre-formatted text you can just use the &lt;pre&gt; tag.  But what is the reason?  More precisely, why is this in the specification for HTML? Use Outgoing SSH to receive incoming SSH My ISP does not allow me to have a static IP address. As such I am unable to remotely SSH in my home machine. Is there a way I could SSH from my home machine to a server and SSH into the server from my remote laptop and bridge the two connections?  Cheers! How do I install make?