Is there EVIDENCE (proof) that time dilation actually occurs in the case of relative UNIFORM mottion (i.e., where no acceleration or decelleration occurs)? By proof, I don't mean mathematically but, instead, in observerable reality. No one answered this simple question. I raise this because to say in such a case that, from BOTH reference frames, the "moving" cliock is ticking slower than the "stationary" clock is a LOGICAL CONTRADICTION . Even invoking relativity of simultaneity where one clock begins ahead of the other, the period of supposed dilation is overlapped by both frames.
It is said that we can verify time dilation by flying a very accurate clock on a fast jet or spaceship and prove that it registers less time than the clocks on earth. However, the clocks on earth would be moving relative to the clock on the spaceship, and since time always dilates and never goes faster regardless of the direction of relative motion,  the clocks on earth should register less time than the clock on the spaceship.  Is this true? Whenever there is a fast-moving object such as a rocket do all clocks on earth really become slow?  If the rocket with the clock landed after moving at relativistic speed, would its clock and the earth's clock again show the same time since during its travel both appeared slow to each other?  Or is all this just an illusion, ie. the clocks just appear to be slow to each other but in actually run at normal speed, and neither is behind when the rocket actually lands?
On Ubuntu 18.04, I have connected my laptop to an external display and I am able to set the external display as primary and external display only mode. But when I turn on my laptop or log out from my session the display login screen is displayed only on my(internal) laptop screen. But once I login the display switches to external only and my laptop screen turns off as expected. Is there a way I can make the login screen appear only on the external screen on bootup or on logout as in 16.04? Also the login screen does not follow my cursor as in 16.04. My book gives the following definition:     Let $(M,d)$ be a metric space, and let $\mathcal{T}$ be the collection of all subsets of $M$ that are open in the metric space sense...  $\mathcal{T}$ is called the topology generated by d   Then it later says to prove things about two different metrics generating the same topology. However I'm very confused about what all this means.   When I read "all subsets," I think of the theorem that says a set with $n$ elements will have $2^n$ subsets. (ex. all the subsets of $\{1,2,3\}$ are $\{\emptyset, \{1\},\{2\},\{3\},\{1,2\},\{1,3\},\{2,3\},\{1,2,3\} \}$). So I think "all subsets that are open" would be like, If M is the set (1,5), then an open subset would be any set $(a,b)$ where $1&lt;a&lt;b&lt;5$, and then all subsets would be all possible union combinations of these "$(a,b)$" sets.     Its seems to me that metrics have nothing to do with subsets. Clearly there is something i'm not understanding. Please Help me.   It would be very enlightening, if someone could give me some simple examples of 1 set and 2 metrics generating two different typologies. WSOD after migrating to another site? Troubleshooting a site migration Movie Identification: People record their experiences on reel-to-reel I know that this sounds like Strange Days, which I haven't seen, but from the Wikipedia description I don't think that's it.  I saw this back in the early-to-mid-90's on TV, pretty sure it was a premium channel. It follows a research group who develops a way to record experiences. Not thoughts, but at least the sights, sounds, smells, touch, etc. They record it onto this reel-to-reel tape, it looked striated and golden in color. The protagonist is the head of the research team.  I don't remember a great deal of the plot, but there were conspiracies surrounding the invention. The lab clown decides to give it a whirl by putting the bike-helmet-sized apparatus on his head and going out to have a little fun, in the classic wine, women, and song fashion. Once he returns, an older member of the team finds the tape and finds a section where the clown is having sex. Later on, the protagonist, who is the lead researcher, finds the older member shut up in his house seemingly for days and nearly comatose. The older researcher had the playback device over his head and is non-responsive. Worried, the protagonist removes the helmet and puts it on himself, only to find that the older researcher had snipped a few seconds of tape and had them running on a non-stop loop; the moment of orgasm for the clownish researcher. The older researcher eventually comes to and awkwardly apologizes.  I think there were also experiments in recording the sensorum of a lab monkey, and that played into the plot. I remember the plot seemed fairly thin and dull for what seemed to be a pretty neat idea. I don't desperately feel the need to watch the movie, but I'm mildly curious if my impressions would differ 20 years later now. Smaller vs. less vs. lesser I am confused as to some of the vocabulary that can be used to compare numbers and quantities, and would very much appreciate some clarification.   I suppose it is safe to say that 1 is smaller than 2.   Can I also say that 1 is less than 2, and if so, which form is preferable?   It seems that saying that 1 is lesser than 2 is uncommon - but is it incorrect?   Finally, -2 is clearly less than -1, but is it true that -2 is smaller than -1? (If I have 2$ of debt, then I would say that I have less money than if I had 1$ of debt, but I would also say that my debt was larger, not smaller). Is it purely a 'gotta-have-them-all' mindset, or do they actually serve some purpose?  I notice that you are able to sell them on a community market. For a test I listed one, and someone bought it for 50p. Not exactly a huge amount, but I don't understand why someone would spend real money on them.  Am I missing something?   Are they redeemable for games or money off vouchers or something 'tangible' that I'm missing? I've seen documentation whereby an \alph command is put around the \begin{enumerate} somewhere, but I'm not entirely sure how that operates... I have installed the pimd service by means of apt. This comes with an upstream systemd unit file (/lib/systemd/system/pimd.service).  I want the service to be restarted when for some reason it gets killed, hence I wish to add the line Restart = always in the unit file.   However, I don’t want to modify the upstream unit file.  Is there any workaround for this? Suppose I have a program named any_program.exe and my operating system drive is C:. The location of the program is D:\Any_Folder\any_program.exe  How do I start/execute that program via command prompt in Windows 8?  I have tried the command line START any_program.exe, but it shows me an error that      Windows cannot find 'any_program.exe'. Make sure you typed the name correctly, and then try again.   By the way, it worked perfectly in Windows 7. And, if I type START notepad.exe or START firefox.exe (Firefox is not installed in C: drive), it works in Windows 8. I never know how to order food correctly but succinctly the first time. :(  Basically: I can't eat hot stuff (i.e. most pepper, similar spices, ...).  On the one hand, I don't want to say "Please don't make it spicy", because I really don't mind spice (heck, a lot of them are great!) -- I just don't want it to be hot spice.  On the other hand "Please don't make it hot" would seem to imply I'd like my food cold!  Possibilities I've considered:   "Please don't add hot spice" just sounds weird "Please don't add pepper" is the best I've thought of so far, but I'm pretty sure I've come across foods without pepper (or apparently so) which nevertheless tasted pretty hot. And not just that, but it would also exclude bell peppers, etc. which I don't mind much.   Any ideas for how to communicate this clearly? The fewer words the better, haha. Given a message and DES encrypted form of said message, is it possible to efficiently compute the key used to encrypt the data? I need help to find the Galois Group of $x^5 +1$. I know that it has a 5-cycle and a 4 cycle and is not a subgroup of $A_5$. Thanks! Spotlight overrides first character What's wrong: I hit CMD+SPACE to open up spotlight, typically type in the name of the application I want to start, hit enter and either the wrong app or no app at all will start, because the app name is missing the first character. "Learn to type" I hear you say but wait: as I enter the first character in the search bar, the cursor jumps to the beginning of the line and my second character input overrides the first one. So entering for example "ever", in order to start Evernote, will result in "ver". "php" to start PHPStorm will result in "hp" and start my damn HP printer app and so on.   This cursor jump to the beginning of the line will not happen in any other application and even if I accept the fact that my cursor jumps from time to time, I don't get why the second character overrides the first one. I'm not even sure if you can configure your Mac to always override the character at current position, but I surely haven't.  So this keeps on happening quite regularly and I cannot reproduce it. It just happens and when I try it again (close Spotlight, CMD+SHIFT again), it won't happen again, even if I give it like 5 tries or so.  It won't kill me but I am a software developer myself and this kind of bugs just leave me frustrated plus I can not imagine that this is the desired behavior. I have seen some talk about this issue on the internet but I did not come across a solution..  I have 3 MacBooks, different ages, all with German keyboard layouts and German set as system language and they all do this. Just mentioning this, because after that fact, I can barely imagine this isn't affecting at least a lot, if not all, MacBook (Pro?) users.   13" Pro 2010 or so 15" Pro Retina 2013 13" Pro Retina 2015   They all run El Capitan but I already encountered this before. I don't know the OS X version I had installed when I first stumbled across it. What's the difference between "cardinal" and "ordinal" as adjectives? UIRefreshControl without UITableViewController factorization of a^n+1? Can we use media9 to show a video on a PDF but the video is not embedded to the PDF? I have video tutorials that I want to show in my presentation with beamer class. I don't want the video files get embedded to the PDF because they will make the PDF size very very huge.  If you know how the videos can be played on the HTML with a reference rather than embedding the video file to the HTML file, I want something like this to be applied to my PDF presentation. I just want to reference the video URL from my PDF presentation.   Shortly speaking, can we use media9 to show a video on a PDF but the video is not embedded to the PDF?  Uploading those videos to a web server might be difficult for me because internet connection is very slow and sometimes not available in the presentation room. :-) Calculate sum of series $\sum \frac{n^2}{n!}$ I have to calculate sum of series $\sum \frac{n^2}{n!}$. I know that $\sum \frac{1}{n!}=e$ but I dont know how can I use that fact here.. Error message "sudo: unable to resolve host (none)" How to delete all music on my iPhone