The universe is said to have begun as a singularity, but how do we know nothing else existed? When I imagine the big bang, I first imagine a tiny ball surrounded by black void. Then the ball explodes and the universe begins. I assume most physicists have the same basic idea.  But how do we know nothing was around that tiny ball when it exploded? It seems like any existing energy/matter at the time of the big bang would have become mixed up with the energy/matter from the singularity, thus rendering it indistinguishable. That means something else could have existed at the time of the big bang, but we can't say for sure.   Has this been ruled out? If so, why? If not, how is it taken into account?
Did the Big Bang happen at a point? TV documentaries invariably show the Big Bang as an exploding ball of fire expanding outwards. Did the Big Bang really explode outwards from a point like this? If not, what did happen?
How do we know the universe is expanding, and not that its contents are shrinking? Is there a physical reason why not to think that instead of space expanding, all physical constants and parameters are shrinking (including of course the instruments we use to measure the constants) and space is static, or is it a case of Occam's razor? I am pretty sure that this is such a stupid, stupid question, but how do you prove that $d_2(x,y)={|x-y|\over {1+|x-y|}}$ satisfying the third condition to be a metric, which is the triangle inequality.   I know that I should really be able to do this, but I just can't, I keep seeing a contradiction. Please help me. Should the first word after a colon be capitalized? Which of the following is correct?   For example: This. For example: this. I'm setting up an Nginx web server and and want to perform load balancing using the round robin method.  This is what I have found thus far:  upstream backend  {    server backend1.example.com;    server backend2.example.com;    server backend3.example.com; }   According to the page they says i need to add the above lines to my nginx.conf file and upload it to server to load balance.  I do not understand what it means by server backend3.example.com;.  How do I setup a backend instance? Proof that $ p $ | ${ p^n \choose k } $ for any prime $p$ and $ k < p^n$ I know how to prove the fact that $ p$ | ${ p \choose k } $ (when writing it as a fraction, $p$ cannot be divided by any of the $1\times2\times...\times k$ or $1\times2\times...\times(p-k)$ because $p$ is prime).  When I try to apply the same rationale for $ p$ | ${ p^n \choose k } $ I get stumped because $p^n$ is in fact divisible by one of the $k! = 1\times2\times...\times k$, where $0 &lt; k &lt; p^n$.  If we take the example of $2^3$ and $k = 7$, we can easily see that $k! = 1 \times 2 \times ... \times 6 \times 7$, and $2$ clearly divides $2^3$.  How else can I approach this? Extract substring in Bash Squeezing all the SEO out of a URL as possible I am working on an ecommerce site, I told our SEO consultant that I plan to make the URL scheme: /products/&lt;id&gt;/&lt;name&gt;. This is similar to Stackoverflow's URLs which are /questions/&lt;id&gt;/&lt;title&gt;.  He asked me if I could change the URL scheme to /p/&lt;id&gt;/&lt;name&gt; instead. I know why he wants this change, the word "products" isn't needed to find the correct product, and it doesn't offer any SEO, so shortening it to just p would make the relevant keywords in the &lt;name&gt; weigh more.  His main priority is maximizing SEO, but the part that I don't think he is considering is how this effects the semantics of the site. Also having the word "products" looks like it has meaning and a reason for being there, just having a p looks chaotic and ugly to me. I also don't think it makes that much of a difference does it? Stackoverflow doesn't use /q/&lt;id&gt;/&lt;title&gt; and they do just fine, I do realize that theres many factors at play here though, not just the URL.  So I want some outside opinions on which is the better way and why? "It is not possible to check out a single file. The finest level of checkouts you can do is at the directory level."  How do I get around this issue when using Subversion?  We have this folder in Subversion where we keep all our images. I just want to check out one file (image) from that. This folder is really big and has ton of other stuff which I don't need now. This is one thing that keeps bugging me, and maybe there's a direct answer. Grammatically, which one is more correct of these two?  Does it make a difference?  I tried not to do that. I tried to not do that. Lightning aura:iteration over two objects with dynamic key I want to do simple thing - I want to iterate over list of two objects and use displayColumns as dynamic keys to get values from selectList object:  &lt;aura:attribute name="displayColumns" type="String[]"/&gt; &lt;aura:attribute name="selectList" type="Object[]"/&gt;   &lt;table&gt;     &lt;aura:iteration items="{!v.selectList}" var="elem"&gt;     &lt;tr&gt;         &lt;aura:iteration items="{!v.displayColumns}" var="col"&gt;             &lt;td&gt;{!elem[col]}&lt;/td&gt;         &lt;/aura:iteration&gt;     &lt;/tr&gt;     &lt;/aura:iteration&gt; &lt;/table&gt;   In pure JS I would do: elem[col.value], but in lightning compiler returns:      expecting a positive integer, found 'col' at column 6 of expression:   elem[col.value]: Source   Is there any workaround without creating proper object structure in controller? I see an increased quantity of "are you a bot" captcha.  What can I do to reduce the quantity of these?  I use Google Chrome on iOS. I have "save bandwidth" turned off. (This feature uses a caching compressing proxy at Google). I connect using 3G over giffgaff uk (which uses the o2 network).  I have an account with over 4k rep on the  site. I visit every day, I vote frequently but not anything unusual. How do I install Skype? I want to install Skype, but I can't locate it in Software Center or by using Synaptic Package Manager. Can anyone help me? Security Review - CRUD/FLS Checks for every SOQL Query I know this sounds like a standard question, so please bear with me.  Recently our Security Reviews fail due to CRUD/FLS violations. The highlighted codelines include almost every SOQL Query in the application.  Our approach is usually as follows:   In case of displaying data on VF pages we either use sObjects fields or use the platform methods to check the accessibility of the fields In case of domain logic triggered by the user (e.g. by clicking a button on a VF page) we have a helper class that checks every field to be updated before doing the DML operation.   Up until recently this approach has worked fine (and passed pervious Security Reviews). As mentioned above the latest Security Review results seem to require us to check every field in a SOQL query for accessibility even if it is never displayed back to the user.    Let's suppose the following program flow as an example:   Query an object with some fields Perform some modification on said fields Perform an update on the sObject to save the modification using a helper class which checks for the required CUD/FLS rights for the modified fields   As I see it there is no need for checking field accessibility in step 1 in that case (since nothing is displayed back to the user and the dml operation is already protected). Is that correct or am I missing something? So is it really required to do an accessibility check for every SOQL Query in the code?  Another question would be how to handle background operations in that case like data purging. These have either to be running in system mode (which causes issues during the Security Review) or require the job to be started by a user with the appropriate access rights (which can be error prone and is not that user friendly). Is there any best practice regarding that.  Unfortunately I could not find a question targeting exactly that issue. Most of the questions I have found are related to how to perform that check (like  or ). So please apologize in case the question was already answered (I would really appreciate a link to the answer then).    Thanks for your time and help.  Mathias I know that one can use "they" / "them" / "their" in place of "he" / "him" / "his" or "she" / "her" / "hers" when the subject's / direct object's gender is not known; for instance, just looking at the default user's about me section on Stack Exchange sites:     Apparently, this user prefers to keep an air of mystery about them   My question is what happens when someone wants to reference the subject using a pronoun instead.  Should the verb be conjugated accordingly to the pronoun? E.g.:     Apparently, they prefer to keep an air of mystery about them   Or should the conjugation be retained? E.g.:     Apparently, they prefers to keep an air of mystery about them   The former looks unclear because it wouldn't allow the reader / listener to understand if the writer / speaker is talking about a single person or about a group of people, however the latter sounds very weird, at least just to the non-native speaker which I am. get list item by id using COM sharepoint 2013 I need to get item from list sharepoint by Id I use this code and it give me all the items of the list :  &lt;script&gt;  function parseURLParams(url) {         var queryStart = url.indexOf("?") + 1,             queryEnd = url.indexOf("#") + 1 || url.length + 1,             query = url.slice(queryStart, queryEnd - 1),             pairs = query.replace(/\+/g, " ").split("&amp;"),             parms = {}, i, n, v, nv;          if (query === url || query === "") {             return;         }          for (i = 0; i &lt; pairs.length; i++) {             nv = pairs[i].split("=");             n = decodeURIComponent(nv[0]);             v = decodeURIComponent(nv[1]);              if (!parms.hasOwnProperty(n)) {                 parms[n] = [];             }              parms[n].push(nv.length === 2 ? v : null);         }         return parms;     }  $( window ).load(function() {   var urlString = document.URL;  urlParams = parseURLParams(urlString);  ExecuteOrDelayUntilScriptLoaded(retrieveActualite, "sp.js");          var siteUrl = '/sites/securite';      function retrieveActualite() {              var clientContext = new SP.ClientContext(siteUrl);             var oList = clientContext.get_web().get_lists().getByTitle('Actualite');             var camlQuery = new SP.CamlQuery();              camlQuery.set_viewXml('&lt;Query&gt;&lt;Where&gt;&lt;Eq&gt;&lt;FieldRef Name=”ID” LookupId="TRUE"/&gt;&lt;Value Type="Text"&gt;' + urlParams.IdArt[0] + '&lt;/Value&gt;&lt;/Eq&gt;&lt;/Where&gt;&lt;/Query&gt;');             this.collListItem = oList.getItems(camlQuery);             clientContext.load(collListItem);             clientContext.executeQueryAsync(onQuerySucceededActualite, onQueryFailed);         }          function onQuerySucceededActualite(sender, args) {              var listItemInfo = '';              var listItemEnumerator = collListItem.getEnumerator();             while (listItemEnumerator.moveNext()) {                 var oListItem = listItemEnumerator.get_current();                   var desc=oListItem.get_item('Description');                 $('#idArticle').append('&lt;label class="titleArticle"&gt;'+oListItem.get_item('Title')+'&lt;/label&gt; &lt;br&gt;&lt;br&gt;&lt;p class="ContenuArticle" &gt;'+desc+'&lt;/p&gt;');                          }         }          function onQueryFailed(sender, args) {              alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());         }       });    &lt;/script&gt;   so how can I get only the considered item ? Connecting two Ethernet PHY without magnetics? How to run specific test cases in GoogleTest Is it possible to only allow specific packages updates from a PPA How to mount a virtual hard disk? Is it possible to mount a virtual hard disk (VHD, HDD, VDI, VMDK) on Ubuntu? How can this be done? Is there any value in full 'beginner's kit bundles'?