Does Stephen Hawking believe that General Relativity is wrong?
Why does Stephen Hawking say black holes don't exist?
“Airplane Mode” in OS X. Alternative command for `rfkill`? Mac OS X doesn't recognize rfkill from its terminal, and I am looking for an alternative command that has similar functionality (toggling "Airplane Mode").  NOTE: I don't wish to open an .app to toggle. I'd like to execute the command from command line or within script in Bash (or equivalents).    By "Airplane Mode", I meant to borrow the term from iOS support page . I would like to disable all incoming/outgoing network communications from my system. Inverse of Heine–Cantor theorem I can’t get used to the new Unity system. I’d like to move the left Unity panel to the bottom of screen (like Windows 7 – more similar is better).  But I can't find a way. Is it possible? Evaluate $\int_{\gamma} \frac{ |dz| }{z} $ where $\gamma $ is the unit circle I need to evaluate $\int_{\gamma} \frac{ |dz| }{z} $ where $\gamma $ is the unit circle.    Attempt: Let $\gamma(t) = e^{it} $ where $t \in [0,2 \pi]$. How can I get rid of the absolute values in the differential? More Question Filtering options I realize that this may be a big request, but...  I think that instead of tabs on the recent question activity pages, or more likely as a new tab, adding a more advanced filtering option.  For instance, being allowed to exclude tags, filter by accepted answers or not, and, most importantly, being able to combine multiple filters!  E.g.: Filtering posts with tag Javascript without tags Jquery and AngularJS with no accepted answers and a score >= 0.  I feel like this is a biggish change that, if implemented as a new tab, wouldn't be that hard to implement, but would be very useful. The word that always gets me mixed up : JUST I had just arrived at the hotel, checked in and gotten into my room. Just as I was about to unpack, I noticed that one of my bags was missing. At first I thought I had left it back at the airport, but it turned out that I had left it on the taxi.  Here, what's the meaning and role of "just"?  Why do you guys input the word "just" here?  What exactly does the word do grammatically?   Could you help me? Autofill feature isn't iterating numbers properly when using the AVERAGE() formula in Microsoft Excel I have a question about the following problem from a Putnam review:  Let $n\in \mathbb{N}$. Find how many pairs of natural numbers $(x, y)\in \mathbb{N}\times \mathbb{N}$ solve $$ \frac{xy}{x+y}=n. $$  I have found some solutions for all $n$, such as $(2n, 2n)$ and $(n+1, n(n+1))$, but I feel as though this is the wrong approach, as the question is only asking for the number of solutions to the equation.  I don't really want a complete solution, but any hints would be greatly appreciated. Visa for transit in Seoul Why does everyone do 9-overlord, not 10-overlord? Why do professional print houses use gamut-limiting CMYK? I recently had some business cards printed, and was warned to use the CMYK colour space if providing TIF files.  When I tried saving from Paint Shop Pro to a CMYK, of course the colours came out very much duller, so I provided a different file type that preserved my colours using RGB. To my horror, the cards came back nevertheless converted to the CMYK dull shades.    A few months previously I had been in a hurry and had printed my own one-sided quasi business cards using glossy photo paper and a cheap home printer.  This reproduced my desired colours perfectly.  Since the whole point of using professional printers is quality (though I admit bulk as well), why do they not use printers that can cope with the RGB colour range?   FYI: the main colour in question, which I chose very carefully, is a slightly yellow-tinged lawn green, which I understand doesn't feature in the CMYK gamut.  So why use that gamut, and is there anything I can do to overcome this issue and get cards printed in the colour I have chosen? Linux command line. Move all files and directories in directory, except some files and directories How do I get attention for old, unfixed bug reports and feature requests without official responses here on Meta? I posted a question here on Meta Stack Exchange, or on a per-site meta, regarding a bug I found in the system. I got no comments, or a few comments stating that this is a legitimate bug (and not by design). However, it's been quite a long time, and no official response was ever posted there.  Or, I had an idea for a new feature, but realized it's already requested, either by searching or posting a request myself only to have it closed as a duplicate of the existing one. It's been a while since the original request was filed, but no official response has been made.   I'm aware that staff members are , but either my post isn't about one of the indicated topic areas for which they're accepting escalation requests for that month, or I already flagged to request escalation but it was declined, so the instructions there don't apply for my post.  What can I do to draw attention to meta questions for the SE team, so they can give an official response, and possibly implement the bug fix or feature?  Note: This is different from other general questions which ask for how to get attention for unanswered questions, since the procedures on meta sites are different, and getting an official response isn't necessarily the same as getting a good answer. Why doesn't bash expand this variable when I prefix a command with a "one time variable assignment" If I run this bash command and prefix the statement, so that the variable fruit should exist, but only for the duration of this command:  $ fruit=apple echo $fruit  $   The result is an empty line. why?  To quote a comment from wildcard on :     parameter expansion is done by the shell, and the "fruit" variable is   not a shell variable; it's only an environment variable within the   environment of the "echo" command   An environment variable is still a variable, so surely this should still be available to the echo command? A (highfalutin) word for a highfalutin word? To illustrate the question, badroit used the word "meretricious" meretriciously.   Is there an English word that describes highfalutin words like "meretricious" that are (gratuitously) used in place of better-understood words like "garish"?  The word may or may not be self-describing. Is floating point math broken? Consider the following code:   0.1 + 0.2 == 0.3  -&gt;  false   0.1 + 0.2         -&gt;  0.30000000000000004   Why do these inaccuracies happen? Inequalities for combinations of $\int f $ and $\int (1/f)$ where $m\le f\le M$ on an interval How to declare a structure in a header that is to be used by multiple files in c? If I have a source.c file with a struct:  struct a {      int i;     struct b {         int j;     } };   How can this struct be used in another file (i.e. func.c)?  Should I create a new header file, declare the struct there and include that header in func.c?  Or should I define the whole struct in a header file and include that in both source.c and func.c?  How can the struct be declared extern in both files?  Should I typedef it? If so, how? How to find solutions of linear Diophantine ax + by = c? I want to find a set of integer solutions of Diophantine equation: $ax + by = c$, and apparently $\gcd(a,b)|c$. Then by what formula can I use to find $x$ and $y$ ?   I tried to play around with it: $x = (c - by)/a$, hence $a|(c - by)$.     $a$, $c$ and $b$ are known. So to obtain integer solution for $a$, then $c - by = ak$, and I lost from here, because $y = (c - ak)/b$. I kept repeating this routine and could not find a way to get rid of it? Any hint?  Thanks, Chan Redefining nodata value into zero in QGIS I have an image which I clipped with an AOI polygon. The contour area was set to pixel value = 0 and I have a nodata value of -32768. I want to redefine the nodata value into zero. I used to do this with ArcMap easily in the raster calculator, but in QGIS I don't see how I could do it. Any ideas?