How do starships always know which way is 'up'? When starships meet in space, they are always topside in the same way. Wouldn't it be totally random? I can understand when a ship is in orbit that the planet is 'down', but even then, it should make no difference.
Why do Star Trek vessels always approach each other on parallel planes? Space is just open 3D space, right? In Star Trek, ships are always coming from somewhere else: different solar systems, galaxies, etc. However, when they meet, they always seem to be on parallel planes (facing each other).  In some episodes I recall seeing ships that were adrift (and they appeared facing a different trajectory). How can there possibly be some standardized reference plane in space? Do ships just choose to align with each other to be polite? Or perhaps when entering a solar system, the pilot, or navigation system aligns orthogonally with the local orbital axis?
Probability brain teaser with infinite loop I found this problem and I've been stuck on how to solve it.     A miner is trapped in a mine containing 3 doors. The first door leads to a tunnel that will take him to safety after 3 hours of travel. The second door leads to a tunnel that will return him to the mine after 5 hours of travel. The third door leads to a tunnel that will return him to the mine after 7 hours. If we assume that the miner is at all times equally likely to choose any one of doors, what is the expected length of time until he reaches safety?   The fact that the miner could be stuck in an infinite loop has confused me. Any help is greatly appreciated. (I was requested to edit the question to explain why it is different that a proposed duplicate question. This seems counterproductive to do here, inside the question it self, but that is what I have been asked by the site and moderators. There is no way for me to vote against their votes. So, here I go: Please stop voting this as a duplicate so quickly, which will eventually lead to this question being closed off. Yes, the other question linked to asks the same math, but any newcomer to the problem who was exposed to it via physics, as I was, will prefer this question instead of the one that is purely mathematically. I beg the moderators to not be pedantic on this one. This question spills into physics, which is why I did the cross post to the physics forum as well.)  How does the sum of the series “1 + 2 + 3 + 4 + 5 + 6…” to infinity = “-1/12”, in the context of physics?  I heard Lawrence Krauss say this once during a debate with Hamza Tzortzis (). I found a transcript of another debate between Krauss and William Lane Craig which has the same sum. Here is the paragraph in full:     Let’s go to some of the things Dr. Craig talked about. In fact, the   existence of infinity, which he talked about which is   self-contradictory, is not self-contradictory at all. Mathematicians   know precisely how to deal with infinity; so do physicists. We rely on   infinities. In fact, there’s a field of mathematics called “Complex   Variables” which is the basis of much of modern physics, from   electro-magnetism to quantum mechanics and beyond, where in fact we   learn to deal with infinity; without the infinities we couldn’t do the   physics. We know how to sum infinite series because we can do complex   analysis. Mathematicians have taught us how. It’s strange and very   unappetizing, and in fact you can sum things that look ridiculous. For   example, if you sum the series, “1 + 2 + 3 + 4 + 5 + 6…” to infinity,   what’s the answer? “-1/12.” You don’t like it? Too bad! The   mathematics is consistent if we assign that. The world is the way it   is whether we like it or not.   -- Lawrence Krauss, debating William Lane Craig, March 30, 2011  Source:   CROSS POST: I'm not sure if I should post this in mathematics or physics, so I posted it in both. Cross post:   EDIT: I did not mean to begin a debate on why Krauss said this. I only wished to understand this interesting math. He was likely trying to showcase Craig's lack of understanding of mathematics or logic or physics or something. Whatever his purpose can be determined from the context of the full script that I linked to above. Anyone who is interested, please do. Please do not judge him out of context. Since I have watched one of these debates, I understand the context and do not hold the lack of a full breakdown as being ignorant. Keep in mind the debate I heard this in was different from the debate above. Help me to get command or ansibile Regex to fetch below details Seriously, I had not noticed e.g. Jeff's edit  had he not also retagged my question. How to mathematically evaluate a string like "2-1" to produce "1"? Is it possible to use the startup.blend UI layout in older files? Is there a way to open files without changing the UI layout?  Sometimes in older files the layout will be in the old 2.4x style, which can be annoying.  One way would seem to be appending everything in, but that gets tedious with having to do it over again and again for objects, materials, textures, etc. The only thing I need is an exact copy of an existing shapefile in the same directory with a different name.  I have tried:   arcpy.CopyFeatures_management (ORLinks, MyLinks) #ORLinks: old links, MyLinks: new links   but for some reason, I cant make it a feature layer using:  arcpy.MakeFeatureLayer_management(MyLinks, 'MyLinks')   Error Encountered:  Error: Failed to execute. Parameters are not valid. ERROR 000732: Input Features: Dataset  M:\RAIL\Rail2.0.shp does not exist or is not supported Failed to execute (MakeFeatureLayer). Setting default values (conditional assignment) In Ruby you can easily set a default value for a variable   x ||= "default"   The above statement will set the value of x to "default" if x is nil or false  Is there a similar shortcut in PHP or do I have to use the longer form:  $x = (isset($x))? $x : "default";   Are there any easier ways to handle this in PHP? Force LaTeX image to appear in the section in which it's declared Possible Duplicates:           How can I force an image in a LaTeX documents to appear in the section in which I declared it?  I don't want that an image about "Section A" to appear in "Section F". :(  I actually include an image with  \begin{figure}[ht] \begin{center} \includegraphics[scale=0.7]{./img/RobotManipulator3D_WorkSpace.png} \end{center} \caption{3D View of the robotic workspace (in red).} \label{Img:3DRobotWorkspace} \end{figure} How to delete kexts in Catalina? I have a 2014 MacBook Pro experiencing . Catalina does not allow kexts to be deleted via this method. Unless I am able to delete or disable this kext my laptop will shut down randomly. Anyone know how to remove kexts in Catalina? JAXB Java generating XML, Why lowercase? Is denying "Paradoxical Partitioning" equivalent to accepting the Axiom of Choice? In  (to ) it has been noted:     One more point to make about the paradoxical decomposition to more parts than elements [...]   currently we do not know of any model of +$\lnot$ where such decomposition does not exist.    Namely, as far as we know, in all models where choice fails there is some set which can be partitioned into more parts than elements.   (Just for clarification: From the context of the above references the comparison "more parts than" is obviously meant in terms of the  of the suitable  being strictly larger than the cardinality of the suitable initial set itself.)  Now, I find the negation or denial of such "paradoxial partitioning" interesting; i.e. the statement (proposition, "$\lnot$PP"):  "Each partition of each given set has cardinality less than, or at most equal to, the cardinality of the given set."  And I like to further explore how this suggested "proposition $\lnot$PP" (being considered along with ZF, of course) relates to "the standard set theory including Axiom of Choice", . Therefore  My questions:      Are there any models of ZFC known (or could there be any such models, in principle) in which there is some set which can be partitioned into more parts than elements ?  And:  Are there any models of ZF known (or could there be any such models, in principle) in which there is no set which can be partitioned into more parts than elements, and which is not also a model of ZFC ?  (And just for reference: Is there a conventional or concise way of expressing the suggested "proposition $\lnot$PP" in terms of standard notation, such as used in the sources linked above? Has it perhaps been discussed already, by some other name? ...) Referee says the proof is wrong, but it is not, what to do? About 3 months ago, my co-author and I submitted a mathematical paper to a journal. Yesterday, we got the editor's response and the paper has been rejected. The reason is that the referee thinks that our results are wrong or trivial.  However, we carefully read the referee's report and we conclude that the "errors" pointed out by the referee are not errors at all and that our proofs are correct. In all modesty, we think that the referee understood very poorly even the statements of our theorems.  Personally, this is the first time that such a situation occurs to me. I already have four papers published in such journal and the reports I got from the referees have been always really accurate.  What do you think is the best thing to do? Forget about and try another journal? Write an e-mail to the editor explaining why we disagree with the decision? Other ideas?  EDIT: Thank you very much for all your answers. At the end, we submitted our paper to another journal with only some slight edits we have already planned to do independently by the referee's report. Boy goes insane during space travel I'm trying to remember the name of a short story I read about 25 years ago or so. I'd also like to know of any collections it appeared in.   The details I recall involve a family who are embarking on a hyperspace journey. To undertake this journey you have to be put to sleep. One of the children pretends to be asleep, and when the jump is complete the child has gone insane. From the child's point of view the jump lasted for an eternity while in reality it was only a few seconds. revoking apex managed sharing permission I'm using apex managed sharing to grant permissions very similar to how it is done in this example trigger:   However, I also need the ability to revoke or delete this access and having it revert to private. The reason for this is my understanding is that there are only two access options for managed sharing access 'read' or 'edit' with no 3rd option of 'none' or 'private'.  Reference:   I've tried adding the shares to a list and deleting the list and I'm getting the error: DELETE_FAILED, cannot delete owner or rule share rows,   I also noticed there is a field on the share object 'isDeleted' this field however is not writable.  Does anyone have experience revoking or deleting these permissions once they've been created?  Thanks! Using AMPScript, I want to pass from a URL Attribute lookup variables and use these variables in my LookupOrderRows function.   The challenge is that not all lookup variables have to be passed by the URL e.g I might lookup just 'office' or I could also lookup both 'office' and 'score.   I've tried several approaches of Concat the string etc - but can't see to make the lookup work.  Has anyone had any success performing similar?   IF not empty( Requestparameter("office") ) then  Set @field1_name = "OFFICE" Set @field1_value = Requestparameter("office")  EndIf  IF not empty( Requestparameter("specialism") ) then  Set @field2_name = "SPECIALISM" Set @field2_value = Requestparameter("specialism")  EndIf  IF not empty( Requestparameter("score") ) then  Set @field3_name = "SCORE" Set @field3_value = Requestparameter("score")  EndIf   set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc",@Field1_Name,@Field1_Value,@Field2_Name,@Field2_Value,@Field3_Name,@Field3_Value)   My current solution is a lot If then statements and combinations i.e. :  /* OFFICE ONLY*/ IF NOT EMPTY(@input_office) AND EMPTY(@input_organisation) AND EMPTY(@input_specialism)  AND EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office) ENDIF  /* OFFICE + ORG*/ IF NOT EMPTY(@input_office) AND NOT EMPTY(@input_organisation) AND EMPTY(@input_specialism)  AND EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office,"ORGANISATION_NAME",@input_organisation) ENDIF /* OFFICE + ORG + SPECIALISM */ IF NOT EMPTY(@input_office) AND NOT EMPTY(@input_organisation) AND NOT EMPTY(@input_specialism)  AND EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office,"ORGANISATION_NAME",@input_organisation,"SPECIALISM",@input_specialism) ENDIF /* OFFICE + ORG + SCORE */ IF NOT EMPTY(@input_office) AND NOT EMPTY(@input_organisation) AND EMPTY(@input_specialism)  AND NOT EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office,"ORGANISATION_NAME",@input_organisation,"Engagement Score",@input_score) ENDIF /* OFFICE + ORG + SPECIALISM + SCORE  */ IF NOT EMPTY(@input_office) AND NOT EMPTY(@input_organisation) AND NOT EMPTY(@input_specialism)  AND EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office,"ORGANISATION_NAME",@input_organisation,"SPECIALISM",@input_specialism,"Engagement Score",@input_score) ENDIF  IF NOT EMPTY(@input_office) AND EMPTY(@input_organisation) AND NOT EMPTY(@input_specialism)  AND EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office,"SPECIALISM",@input_specialism) ENDIF  IF NOT EMPTY(@input_office) AND EMPTY(@input_organisation) AND NOT EMPTY(@input_specialism)  AND NOT EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office,"SPECIALISM",@input_specialism,"Engagement Score",@input_score) ENDIF  IF NOT EMPTY(@input_office) AND EMPTY(@input_organisation) AND EMPTY(@input_specialism)  AND NOT EMPTY(@input_score) then     set @rows = LookupOrderedRows(@LeadsDE,0,"[Engagement Activity Date] desc","OFFICE",@input_office,"Engagement Score",@input_score) ENDIF I want to keep Ubuntu but remove Windows. Client-Side Rendering/JS Link documentation? Has there been any sort of documentation or anything like that released for SharePoint 2013 Client-Side Rendering/JS Link?  Anthing unofficial? Any dates for when documentation might be released? How can I move my /home directory to another partition if it's already part of the / partition? I have a wonderful running Maverick Meerkat install going on right now. I want to move my /home to another partition as per many suggestions.   How can I go about doing this without reinstalling the entire Ubuntu system? Can I simply create the partition with gparted and then change the mount point of /home in fstab to reflect it or is it a bit more difficult? How do I pass a string into subprocess.Popen (using the stdin argument)?