Please forgive me if this is a stupid question as I have a very rudimentary understanding of physics.  I was reading about how the large hadron collider speeds up subatomic particles to near lightspeed and that the experimenters need to take the effects of time dilation into account because of this. This got me thinking and I came up with a strange thought experiment. Instead of subatomic particles, imagine we could send something like a small vehicle with a few people in it around the "track" (track seems like an inappropriate word but I'm not sure what it's actually called) at near light speed. So imagine they also have a high def webcam with them in the vehicle and that they wirelessly send a video to be broadcast on the internet. What would we see if we were to watch this video? Would they appear to us as if they were in super slow motion?
Consider a hypothetical situation: In which a time traveler travels in a spaceplane at close to speed of light circling the earth and I get a live telecast of inside of that plane to my television. How time dilation will effect him and what will I observe sitting next to the tv seeing him live. Considering time runs slower at speed of light, will he be looking like a slow motion video? (Or let he also watching live streaming of us at earth, what it will look to him) P.S. I'm not sure if it even makes some sense but if it does kindly explain in logical details. Sorry for the the bad english, I'm not a native speaker.
Delete commits from a branch in Git I was held at the Polish borders when I attempted to enter by train. They took my fingerprints and sent me back with a written document. I respected the decision and returned immediately.   The document is in Polish concerning the decision taken, and I don't understand it. I am from Cameroon. My limited understanding from what was explained in English at the time was that the asylum status I requested was denied me. I only realised later that I asked the wrong authorities (border guards instead of immigration officers).  This was exactly one year and three months ago now. Do I still have access to any Schengen country? Given a simple graph and its complement, prove that either of them is always connected. I was tasked to prove that when given 2 graphs $G$ and $\bar{G}$ (complement), at least one of them is a always a connected graph.  Well, I always post my attempt at solution, but here I'm totally stuck. I tried to do raw algebraic manipulations with # of components, circuit ranks, etc, but to no avail. So I really hope someone could give me a hint on how to approach this problem. Name of short sci-fi story involving a musician who is punished for listening to Bach I read a short story a long time ago and I can neither remember the title nor the author.  The main character is a musician.  He is sequestered and allowed to play all day on some kind of a fantastic instrument; however, he has been barred from listening to any music for fear that it will stifle with his innate creativity.  Someone secretes him some Bach, he listens to it, and is then caught and cast out.  He gets a series of jobs and is inevitably punished for breaking some music-related taboo.  Any ideas? A term for when people insist on giving you help you didn't ask for? People love to tell other people what to do. It may not be control, so much as trying to help, especially when you've asked for help directly. However, there's a difference between answering someone's question and answering while piling on recommendations the person didn't ask about, and this is what I'm seeking a term for. Advertising and marketing feel similar to me in this vein. In the worst cases this can be overzealous religious followers professing your damnation if you don't follow with them (I think in Christianity they call it "witnessing"). Any which way, it comes across to me as a form of unsolicited advice: I didn't ask for it, so I don't want it; I want to stay focused.  Is there a better term for this than "unsolicited advice"? Also, is there a term for a person who exhibits this kind of behavior frequently? Linux: clnt_create: RPC: Program not registered NFS mounts recently automatically got un-mounted. When I checked, the NFS service status it was shown to be running.  [root@hsluasrepo]# service nfs status rpc.svcgssd is stopped rpc.mountd (pid 4083) is running... nfsd (pid 4148 4147 4146 4145 4144 4143 4142 4141) is running... rpc.rquotad (pid 4079) is running...  [root@hsluasrepo]# service rpcbind status rpcbind (pid  4203) is running...  [root@hsluasrepo common]# rpcinfo -p 10.80.3.154    program vers proto   port  service     100000    4   tcp    111  portmapper     100000    3   tcp    111  portmapper     100000    2   tcp    111  portmapper     100000    4   udp    111  portmapper     100000    3   udp    111  portmapper     100000    2   udp    111  portmapper   But showmount output was showing an error.  [root@hsluasrepo ]# showmount -e 10.80.3.154 clnt_create: RPC: Program not registered   After restarting the NFS service, showmount output displayed the NFS server's export list.  Can anyone tell me the root cause of this issue and How to avoid this problem in future?  /var/log/messages:  Jul 7 03:22:01 hsluasrepo rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1188" x-info="rsyslog.com"] rsyslogd was HUPed Jul 7 03:22:02 hsluasrepo rhsmd: In order for Subscription Manager to provide your system with updates, your system must be registered with RHN. Please enter your Red Hat login to ensure your system is up-to-date. Jul 8 03:22:01 hsluasrepo rhsmd: In order for Subscription Manager to provide your system with updates, your system must be registered with RHN. Please enter your Red Hat login to ensure your system is up-to-date. Jul 8 16:36:55 hsluasrepo kernel: nfsd: last server has exited, flushing export cache Jul 8 16:36:55 hsluasrepo rpc.mountd[4083]: Caught signal 15, un-registering and exiting. Jul 8 16:36:55 hsluasrepo rpc.mountd[24463]: Version 1.2.3 starting Jul 8 16:36:55 hsluasrepo kernel: NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory Jul 8 16:36:55 hsluasrepo kernel: NFSD: starting 90-second grace period Jul 8 16:37:32 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.208:1004 for /common/PROD (/common/PROD) Jul 8 16:38:09 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.181:869 for /common/PROD (/common/PROD)  Jul 8 16:38:43 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.180:825 for /common/PROD (/common/PROD) Jul 8 16:39:12 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.176:688 for /common/PROD (/common/PROD) What's the rationale for requiring that a field be a $\boldsymbol{non}$-$\boldsymbol{trivial}$ ring? The title pretty much says it all.  Of course, one answer (IMO unsatisfactory) to such questions goes something like "a definition is a definition, period."  In my experience, mathematical definitions are rarely completely arbitrary.  Therefore I figure there must be a good reason for insisting that a field be a non-trivial ring (among other things), but it's not obvious to me.  I realize that a trivial ring would make for a very boring field, but it is also a rather boring ring, and yet it is not disallowed as such.  EDIT: I found a hint of a rationale in the statement that "the zero ring ... does not behave like a finite field," but I could not find in the  for this assertion exactly how the zero ring fails to behave like a finite field. Buster Blader the DDS did not affect Destiny Hero - Decider effect; why so? How come  with  set to dragons didn't stop 's effect from being activated? I've found that while using Vim on Windows Vim saves the file, a .ext.swp file that's deleted on closing the Vim window and a .ext~ file.   I assume the .ext.swp file is a session backup in case Vim crashes. What's the purpose of the .ext~ file however? Is this a permanent backup file? It's annoying as I'd like to copy all the files I'm working on to my host, without these duplicates. How can I turn this off or, if it's there for a good reason, hide the files? Preview on the right please, optionally? 10% rule for sample sizes In an introductory stats book by Nicole Radziwell "Statistics the easy way with R" , an assumption used  for nearly every statistical test (e.g.t-tets, anova, etc) is that the sample size should not be more than 10% of the population size (where the population size in known).   I havent seen it mentioned in other introductory stats books. My question is: how important is theis assumotion and what is the reason for it?  The author didn't say where this comes from (at least as far as I could see). A bit of googling suggests that it refers to making a simple random sample without replacement, if the sample size is above 10% then the observations wont be (approximately) independent, and indepedence of observations is an assumption stated in most textbooks.   In the case where you have a small population (e.g. &lt;50), should you give up on this assumption because it results in sample sizes too small to get decent estimates of variability and to check other assumptions such as normality.    Thank you for any insights. How to test randomness (case in point - Shuffling) First off, this question is ripped out from  question. I did it because I think this part is bigger than a sub-part of a longer question. If it offends, please pardon me.  Assume that you have a algorithm that generates randomness. Now how do you test it? Or to be more direct - Assume you have an algorithm that shuffles a deck of cards, how do you test that it's a perfectly random algorithm?  To add some theory to the problem - A deck of cards can be shuffled in 52! (52 factorial) different ways. Take a deck of cards, shuffle it by hand and write down the order of all cards. What is the probability that you would have gotten exactly that shuffle? Answer: 1 / 52!.  What is the chance that you, after shuffling, will get A, K, Q, J ... of each suit in a sequence? Answer 1 / 52!  So, just shuffling once and looking at the result will give you absolutely no information about your shuffling algorithms randomness. Twice and you have more information, Three even more...  How would you black box test a shuffling algorithm for randomness? Are both of the following sentences correct?  a: You can call me, if you need me.  OR  b: You can call if you need me.  Note that in a:, the comma is placed before the "if" and is not present in case b.  From this link, I gather that it isn't necessary because it's a short sentence:   But can someone point out an "official" source on this usage? Difference between staticmethod and classmethod When transiting between two flights, will my luggage be automatically transferred? The proof I have starts of with $\;xy=0\;$ in a field.   Then $x^{-1}$ exists because it is a field.  Then $x^{-1} xy=x^{-1} 0$.  Therefore $y=0$.  But surely if an integral domain can not have any zero divisors, how can we end the proof by saying $y=0$? Surely then y is a zero divisor and hence the field is not an integral domain? High Memory Usage on Linux Server I am developing a PHP application in which I am in need to store values bigger than 1 million, but with the flexibility of having floating points. I know the traditional float and double. I am looking to store only up to two decimal points, and will only handle operations with numbers that have 2 decimals exclusively.  I have chosen my column type of double and unsigned, but whenever I store a row with a value bigger than one million, it gets truncated to 999999.99  Why is this? I am looking for the right datatype/solution. If you could point me in the right direction, I will appreciate it a lot!  Thank you for your time in advance!  Cheers. Delete an old Facebook account Two years ago somebody made a fanpage for our company, but that person doesn't work here anymore. We don't have any login or password. We like to see that account be deleted, please. Why getting this error tlmgr Unknown directive? I haven't used tlmgr for a while but when I tried to install any package with it today, It returned following message:     (running on Debian, switching to user mode!) Unknown directive ...containerchecksum c59200574a316416a23695c258edf3a32531fbda43ccdc09360ee105c3f07f9fb77df17c4ba4c2ea4f3a5ea6667e064b51e3d8c2fe6c984ba3e71b4e32716955... , please fix it! at /usr/share/texlive/tlpkg/TeXLive/TLPOBJ.pm line 210,  line 5579.   I've tried to use fix specified on :     You have to download update-tlmgr-latest.sh from the tlpretest repository   and run it. Afterwards you will be able to work with tlmgr as usual   (announced by Norbert a few hours ago).   I've downloaded it from , but it returned another error:  Verifying archive integrity... All good. Uncompressing TeX Live Manager Updater............................................................................................................................................................................ ./runme.sh: Cannot find TeX Live root using kpsewhich --var-value=SELFAUTOPARENT. ./runme.sh: Please set your PATH as needed, otherwise it's hopeless.   Minimum example  Install cleanly vanilla TeXLive 2016 with tmlgr after having old TeXLive in the system successfully: there is no errors/warnings in /usr/local/texlive/2016/*.log, complete log example . Run the following but you get the same output as above when trying to update the system  root@masi:/home/masi/Downloads/t/install-tl-20161019# tlmgr update --self (running on Debian, switching to user mode!) Unknown directive ...containerchecksum c59200574a316416a23695c258edf3a32531fbda43ccdc09360ee105c3f07f9fb77df17c4ba4c2ea4f3a5ea6667e064b51e3d8c2fe6c984ba3e71b4e32716955... , please fix it! at /usr/share/texlive/tlpkg/TeXLive/TLPOBJ.pm line 210, &lt;$retfh&gt; line 5579.