We all know the following universal truth since childhood.     Earth (and other planets) orbits around the Sun.   And, while I was reading , I found that the reason behind Earth revolution is chiefly due to one force:   Gravitational pull   Some physicists explains the movement of Earth around the Sun on the basis of the following image:       As we can see, the initial state of rock is rest. And when we apply a force, it starts moving in a circular path.   Now my question is from where the Earth had got the inertia of motion? As the rock in the above example was initially at rest and so the Earth should also be in state of rest (without any force applied on it).
The origin of spin is some what a puzzle to me, everything spin from galaxies to planets to weather to electrons.  Where has all the angular momentum come from? Why is it so natural?  I was also thinking do photons spin? we always think of the wave as a standard 2d sin wave but could this rotate in 3d? What implications would this have?   And what about spacetime how does all the spinning effect?  This has always been avoided in all lectures and classes I ever went to.
Do these new insights into prime numbers affect encryption security? reports:  Two mathematicians have uncovered a simple, previously unnoticed property of prime numbers [...]. Prime numbers, it seems, have decided preferences about the final digits of the primes that immediately follow them. Among the first billion prime numbers, for instance, a prime ending in 9 is almost 65 percent more likely to be followed by a prime ending in 1 than another prime ending in 9.  Do these insights make breaking keys based on primes more mathematically plausible in a shorter amount of time? What is the best way to increase my reputation and privileges? I'm not sure if this is a stupid question, but here goes anyway... I have only recently started learning PHP and Javascript and I'm reasonably proficient. One of the reasons I'm so proficient is because I LOVE Stack Overflow and find most of the solutions to my dilemmas here.   But I've found that I never get the chance to ask a question because it has normally been asked many times before and when I go through the unanswered questions to try and help someone else, they are generally WAY over my head.  So I'm not sure how to get more privileges. I can't even vote up answers that I like or that helped me. I can't comment to thank someone for their solution. It is most tragic and demoralising... How do I change the situation? Disable three-letter pings from chat to save Oliver, Olivier and Olive from Oli's pings What is wrong with this fake proof $e^i = 1$? $$e^{i} = e^{i2\pi/2\pi} = (e^{2\pi i})^{1/(2\pi)} = 1^{1/(2\pi )} = 1$$  Obviously, one of my algebraic manipulations is not valid. Is it possible to use the animals that are summoned using Conjure Animals as mounts?  As an example: Summoning Giant Eagles to carry a group up the mountain or over a wall. Sum with parameter convergence Did the date of Frodo's rescue out of the fire of Mordor have any particular meaning in The Lord of the Rings? What is the best program for image optimizing for the web? What programs besides Photoshop are good for saving and optimizing images for web? modify specific column with sed or awk I have a CSV file that looks like this:  qw12er,foo,0 bn5mgh rt8yp,foo,10 gh78jk bn852mv,foo,852 78ghjkh tgbr,foo,10 ujmyhn wsx2d,foo,0000 ui52ohn tgbr,foo,7418529 ujmyhn ikl896o,foo,22 wsxdc52   I want to modify the 3rd column and remove all numbers and space from the beginning of the 3rd column.  Then output would be as follows:  qw12er,foo,bn5mgh rt8yp,foo,gh78jk bn852mv,foo,78ghjkh tgbr,foo,ujmyhn wsx2d,foo,ui52ohn tgbr,foo,ujmyhn ikl896o,foo,wsxdc52 I was a member of a study team that produced a couple of research papers. The authors of the paper are, for example:      Michael Jordan, Tiger Woods, John Smith and The ABC Study Investigators   In the acknowledgements, it reads:     The ABC Study team consists of members from Harvard University (James Bond, Thomas Harper, David Price, and Jason Jolly)   (Suppose that my name is David Price.)  Can I list such papers in the publication list of my CV? If not, how can I show that I participated in these research papers?  In PubMed, my name was listed as one of 'collaborators.' How to stop apt from doing anything Do I need a UK visa? How and where to apply? For every generation of Excel I can remember (including 2010, which I'm using now), Excel's "Auto Size Row" features sometimes fails to actually auto size a row when the cell contains wrapped text. When it works properly, all the text is revealed and there is no additional space below the last line of text. When it fails, it adds extra space below the text. To make matters worse, what you see is not always what you get, i.e., text that appeared okay on screen gets cut off when it's printed. You also get different sizing depending on whether you are zoomed in/out or at actual size.  Simple test case:  Why is there a one-line gap after the text in cell A1 but not in A2?  (To reproduce: set width of column A to 17.14 (125 pixels), text wrap on, and cell alignment top.)  (I double-checked that I applied Auto Fit Row Height to both rows. Zoom level is 100%.)    Is there any known remedy for this without resorting to manually adjusting the row heights (which is not practical for more than a handful of rows)? Equivalent Rotation using Baker-Campbell-Hausdorff relation Is there a way in which one can use the BCH relation to find the equivalent angle and the axis for two rotations? I am aware that one can do it in a precise way using Euler Angles but I was wondering whether we can use just the algebra of the rotation group to perform the same computation? Background image resize in Ubuntu 18.04.1 LTS Recently updated to 18.04.1 and now I cannot resize my background image from fill screen to center image.  How can I resize the image now that 18 doesnt have the quick resize feature? Journal vs conference publications when looking for a job in in computer science I'm currently a post doc in theoretical computer science and I have a double digit number of conference publications, about half of which are at so called "tier 1" conferences (SODA,STOC,...). Unfortunately I only have 1 journal publication so far, mainly due to coauthors dragging their feet.   Will the lack of journal publications have a great impact when applying for a faculty job in cs-theory at some point, and is it advisable to try to up this number before applying? Or is this fully compensated by having sufficiently many conference papers? Singular or plural verb after parenthetical material containing a conjunction? I would tend to say     Sara (and all of us) have a lot to think about now.   ...but it occurs to me that if I remove the parenthetical it's clearly incorrect. Is it proper to say     Sara (and all of us) has a lot to think about now.   ...that sounds really strange to my ear.  Also, does it change the rules in any way if I use an em dash, e.g.     Sara–and all of us–have a lot to think about now. Find My iPhone Email Notification Is the email notification from Apple that your device has been tracked using Find My iPhone a new feature? Sensitivity to initial conditions and topological transitivity Forgive the possibly naive question, but I'm returning to a basic undergrad-level study of chaotic dynamical systems and can't quite seem to reconcile the notion that in order for a dynamical system to be considered chaotic, it must have positive global Lyapunov exponents. Such exponents, of course, drive the divergence of trajectories. However, topological transitivity implies that trajectories can get arbitrarily close as well over some finite time. It seems that positive Lyapunov exponents would disallow this mixing. Is there a point at which these positive exponents no longer describe the system, and the mixing behavior begins? I just downloaded a DVD which is for a movie. After uncompressing the DVD file I see .VOB, .IFO and .BUP files. If I open the first .VOB file it shows me the DVD menu but I can't interact with it. So, my question is... is Totem able to play those kind of files? If so, how can I achieve that? What other app could I use in order to reproduce those files?  Edit  Using VLC didn't work neither. I forgot to mention I have already tried that. Let me rephrase: if I open the first video file it shows the DVD menu, BUT I can't interact with it.