Looking for recommendations for someone who loves physics but is not in college/university. I'm a 39-year old engineer.
Every once in a while, we get a question asking for a book or other educational reference on a particular topic at a particular level. This is a meta-question that collects all those links together. If you're looking for book recommendations, this is probably the place to start.  All the questions linked below, as well as others which deal with more specialized books, can be found under the tag  (formerly ).  If you have a question to add, please edit it in. However, make sure of a few things first:   The question should be tagged  It should be of the form "What are good books to learn/study [subject] at [level]?" It shouldn't duplicate a topic and level that's already on the list   Related Meta:
How do I set the default program? How do I set the default program that I use?  I have tried to open System Info → Default Program → change my program, but it won't work,  Any idea? Or should I use Terminal?   I want to replace the default movie player with VLC media player, because the current movie player is useless to me. In Star Trek TOS, we see the Defiant disappear to unknown parts  ('The Tholian Web'), and Star Trek: Enterprise revealed that the Defiant went back in time to the mirror universe ('In a Mirror Darkly', parts 1 &amp; 2).   Because of this, one might wonder why (in-universe) the mirror universe didn't obtain (and maintain) technological superiority over the main timeline. (Granted, the out of universe answer is that TOS depicted the two universes as having essentially the same level of tech)  So does any work (whether STO, or a pocket books work) address why the mirror universe didn't simply leap frog the main universe's technology?   (Or to put it another way, why did the mirror universe's technology appear to stagnate for a century after obtaining access to the Defiant's advanced technology?) Cross-referencing problem if counter of theorem-like environments is shared The problem is when i share numbering the \cref can't show name, even by \crefname and \autoref show all name Equation.  Here is an MWE:  %&amp;latex \documentclass{amsart}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % If you want to insert other packages. Insert them here \usepackage{amsthm} \usepackage{hyperref} \usepackage[nameinlink]{cleveref} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  \begin{document}  \numberwithin{equation}{section}  \newtheorem{The}[equation]{Theorem} \crefname{The}{Theorem}{Theorems}  \newtheorem{Dfn}[equation]{Definition} \newtheorem{Lem}[equation]{Lemma} \newtheorem{Prs}[equation]{Proposition} \newtheorem{Crl}[equation]{Corollary} \newtheorem{Rmk}[equation]{Remark}  \begin{The}\label{T1}    Assume ... \end{The}  ... \begin{Dfn}\label{D1}    Assume ... \end{Dfn}  ... \begin{Lem}\label{L1}    Assume ... \end{Lem}  ... \begin{Prs}\label{P1}    Assume ... \end{Prs}  ... \begin{Crl}\label{C1}    Assume ... \end{Crl}  ... \begin{Rmk}\label{R1}    Assume ... \end{Rmk}  \begin{equation}\label{E1}    Assume ... \bigskip \end{equation}  \noindent \cref{T1} \\ \cref{D1} \\ \cref{L1} \\ \cref{P1} \\ \cref{C1} \\ \cref{R1} \\ \cref{E1} \\  \noindent \autoref{T1} \\ \autoref{D1} \\ \autoref{L1} \\ \autoref{P1} \\ \autoref{C1} \\ \autoref{R1} \\ \autoref{E1} \\  \end{document}     How can I solve it? How do I create a PPA? How do I create my own custom PPA to share with the Ubuntu community? I am trying to create my own custom package set and I would really like to share it with the community. OLS is BLUE. But what if I don't care about unbiasedness and linearity? The  mentions that it's possible to post one more question after a six-months waiting period and if the question is good enough, the question ban can be lifted:     If you're unable to improve your existing questions, you'll get the chance to ask one new one 6 months after your last question. If that question is positively received, you may be able to continue asking questions; if not, then the ban will be reinstated.   What is positively received in this context? Is it enough if the question has a zero score and is not closed? Or does it have to have a positive score?  How long does the system wait after posting this new question to evaluate this criteria and possibly lift (or reinstate) the question ban? How should I invest my money as a young graduate in Europe? This is related to this , but that question's answers are 95% tailored for residents of the US, basically recommending to full out the 401k retirement plan and this and that about stock market investments. My question is, are there other types of investments that are good for a young person starting out a career? Pointers:  I live in a welfare state in Europe, so I don't have college debt, (debt of any kind actually). Rainy day funds are much less needed than in the US, since here there is unemployment insurance for at least 18 months. I can probably invest 500€-600€ monthly for something. (The question is what.) I am not looking to invest in my retirement (I am already forced to pay for that out of my salary). I want to maximize my earnings for medium term (5-15 years). I specially want to avoid the typical paradox of (be poor in your 20's,30's,40's and be able to use your money after your 50's). That is not an option for me, I want to use my money for X or Y. But the money used has to be earned from an investment. That is a general rule for me.  For example I want to earn from my investments at least 70k€ after 5-10 years. So I'm guessing this would be a high risk investment, correct? I would like to spend on travel, on courses, on sports etc... But I insist that the money I spend should be a result of an investment not from my salary. Additionally I am not looking to buy a house so I don't want a mortgage. Except if this would constitute a good investment? FYI: this applies to France. But I'd like a general answer so others can benefit. If the question is unclear, a duplicate or off-topic don't hesitate to comment I have a new laptop which I am setting up as dual boot Windows/Linux.    I would like to access files from both Ubuntu and Windows 7.  Should I create a separate NTFS partition? Calculating the integral $\int_0^\infty \frac{\cos x}{1+x^2}\, \mathrm{d}x$ without using complex analysis Suppose that we do not know anything about the complex analysis (numbers). In this case, how to calculate the following integral in closed form? $$\int_0^\infty\frac{\cos x}{1+x^2}\,\mathrm{d}x$$ Where can I find the points per game throughout many NBA seasons? Where can I find the points per game (of both teams) throughout many NBA seasons?  To illustrate my point, what I mean is something like:   2000/01 average points per NBA game: 200; 2001/02 average points per NBA game: 210; 2002/03 average points per NBA game: 205;   so on... JavaScript + Unicode regexes What is reflection and why is it useful? What is reflection, and why is it useful?  I'm particularly interested in Java, but I assume the principles are the same in any language. Get output parameter value in ADO.NET What are the differences between struct and class in C++? Bottom to top explanation of the Mahalanobis distance? Discrepency in unanswered questions counts On , I notice that if I use the lower &quot;unanswered&quot; tab (the one in line with &quot;All Questions&quot;), the count is 1,432 questions. If I use the upper &quot;Unanswered&quot; tab (in line with the site title), I get 1,383 &quot;questions with no upvoted or accepted answers&quot;.  This changes the options in the lower tab, one of which is &quot;no answers&quot;.  Clicking here, I now get 1,083 &quot;questions with no answers&quot;. If I run select Id from Posts where PostTypeId=1 and AnswerCount=0;  in the , I get 1158 rows back. Which of these is correct, and why is the first one (1,432) so much higher than the others?  I understand that the numbers may only be updated periodically, but that difference in particular seems much too great for this to be the reason. To clarify:  1,432 is the number of &quot;unanswered questions&quot;. 1,383 is the number of &quot;questions with no upvoted or accepted answers&quot;. 1,083 is the number of &quot;questions with no answer&quot; 1,158 is the number of questions with no answer in the data explorer.  This is not live data, but that means it should be smaller, not larger, than 1,083.  I promise we did not offset this with answers to the tune of 80 questions this week.  The first three are obviously live because they fluctuate. The difference between the first two is ~50, implying they actually don't refer to the same thing, and the difference between the last two seems too great (and in the wrong direction) to be explained by the a live vs. data explorer source. I'm participating in the  and wanted to refer to the on- and off-topic questions on the  proposal.  However, I couldn't find a link to it anywhere in the SE site.  If I'm not missing the obvious, could we have one? If G is a group of order n=35, then it is cyclic I've been asked to prove this.   In class we proved this when $n=15$, but our approached seemed unnecessarily complicated to me. We invoked Sylow's theorems, normalizers, etc. I've looked online and found other examples of this approach.    I wonder if it is actually unnecessary, or if there is something wrong with the following proof:   If $|G|=35=5\cdot7$ , then by Cauchy's theorem, there exist $x,y \in G$ such that $o(x)=5$, $o(y)=7$. The order of the product $xy$ is then $\text{lcm}(5,7)=35$. Since we've found an element of $G$ of order 35, we conclude that $G$ is cyclic.   Thanks. When an air-filled balloon is released without its opening tied up, it moves in a circular path rather than a straight line. Why is that? What are the regional Pokémon? I have heard that there are some Pokémon that are region specific.  Could someone please clarify which Pokémon are region specific and in which regions that they can be found in?