I'm trying to understand QM and many stuff gets in conflict in my head. Black body radiation means a hot object produces light in certain frequencies. Meaning it's losing energy.  Yet they talk about Thermal Equilibrium, which means the temperature of the object is constant. But can it? if it's losing energy how can an object have constant temperature.  Even in space an hot object would lose energy by producing photons, right? No?
Everytime, I read about blackbody, I always get confused at the point where it is written     Under thermal equilibrium conditions , the blackbody radiation depends only on temperature. ..... . At equilibrium , electromagnetic waves bounce around with the walls of the cavity.   What is this equilibrium all about? Why is it important here?? If there is thermal equilibrium, why does the body radiate?? Please help.
How can I obtain total number of points? How do I transfer a file to my server using PuTTY? Add "Answer Later" Tab I think it would be useful to add an "Answer Later" tab that would be similar to the "Favorites" tab so you could mark questions to answer at a later time. There are so many times I see a question which I would like to answer but don't have time, then I have a hard time finding it again later. Right now I mark it as favorite, go back and answer it, then unmark it as favorite (unless I really like the question).  Do you think other people might find this useful? Do you do this some other way? Occasionally, the Unicode character sequence U+200C U+200B (ZWNJ ZWSP) is inserted into comments In     ... the number "5000" does not paste as such but instead as  5 0 U+200C U+200B 0 0   The HTML source looks like this:  perhaps the easiest would be &lt;code&gt;\edef\tmp{\everypar{\widowpenalty\the\widowpenalty\relax}}\tmp\widowpenalty=-50&amp;zwnj;&amp;#8203;00&lt;/code&gt; that may reset   Or (smaller snippet):  \widowpenalty=-50&amp;zwnj;&amp;#8203;00&lt;/code&gt; that   So in the HTML, we have extraneous &amp;zwnj; and &amp;#8203; in between the two middle digits of 5000.  Upon pasting and trying out this code, this first led to a mysterious compiler error. The same issue happened within a (now deleted) comment thread below ; there, these or similar two characters were inserted after the letter "r" within the string \ref ("\ref").  Note that not all browsers wrap the same way. The above screenshot was for Firefox 19.0.2, in which it breaks between \relax}} and \tmp, with 5000 insidiously left intact on the second line but with the two special characters remaining in the middle. So that is why this took me completely by surprise. Other browsers might indeed only break on the invisible Unicode characters, such as Chrome 25:    Or on a smaller screen with the mobile site, multiple line breaks might show, possibly still leaving the Unicode characters unused: This is a  about hostname-awareness and proxying.   I know that some protocols are hostname-aware; that is, when I connect to the HTTP server at www.example.com it knows I want www.example.com's HTTP service, not www.example.net's, even though they are on the same IP address.  How can I do this for protocol foo?  (Temporary note: this question appears pursuant to .) SF short story ID, written 40s—60s, primitive aliens who are much smarter than us I'm looking for a story that was probably written somewhere from the 1940s to the 1960s. I think I read it in an anthology, possibly in the 1970s.  A group of human explorers landed on a planet with primitive aliens, living in hunter-gatherer villages. They hoped to make a profit from trading our goods for—well, I'm not clear on what they wanted from the aliens.  The native people learned the human language before the explorers could learn theirs. Then the natives suddenly started producing technological innovations far beyond what they originally used. I remember that wooden sailing ships suddenly replaced their canoes. All the natives had to do was hear a story once from the explorers before copying the technology in the story.  Finally, the explorers realized that the natives were much, much smarter than us and that Earth faced a serious problem.  I'm fairly certain that it wasn't a Heinlein story, but I remember that it had some qualities similar to his work. How can I uninstall software? I've completed my contracts. Now what? I completed the two contracts I was given (Scout and Heavy), and earned two of the 'Teufort' weapons for turning them in.  I expected to get some new contracts so I could continue to earn some more of the schmancy new weapons, but I can't seem to find out how to get more.  Do I need to buy the ticket again to unlock more contracts? If not, how are contracts assigned? A list of inconveniences between quantum mechanics and (general) relativity? It is well known that quantum mechanics and (general) relativity do not fit well. I am wondering whether it is possible to make a list of contradictions or problems between them?  E.g. relativity theory uses a space-time continuum, while quantum theory uses discrete states.  I am not merely looking for a solution or rebuttal of such opposites, more for a survey of the field out of interest. The PHB states: "A familiar can’t attack, but it can take other actions as normal."  What can a familiar do? Can it use a potion of healing on a character? Can it drop caltrops? How to get the path of a running JAR file? My code runs inside a JAR file, say foo.jar, and I need to know, in the code, in which folder the running foo.jar is.  So, if foo.jar is in C:\FOO\, I want to get that path no matter what my current working directory is. Probability Math Question...? Bag A contains 3 white and 2 red balls. Bag B contains 6 white and 3 red balls. One of the two bags will be chosen at random, and then two balls will be drawn from that bag at random without replacement. What is the probability that the two balls drawn will the be the same color? Express your answer as a common fraction. Series as an integral (sophomore's dream) Is it appropriate to use short form of "have" ('ve) when it means possession? I feel uncomfortable saying sentences like the following:    "I've a car" instead of "I have a car" "They've a great time" instead of "They have a great time" "He's a pen" instead of "He has a pen" etc   I ask this because I read this sort of thing in a book.  Are they correct? And what is the rule? Can you use such forms in a formal setting? How to set Command Block(s) to test for a particular time and output a message? I need to build a list of files present in a directory but also pass in a file containing a list of directories to exclude.  I've seen the below suggestion but I've had no luck with it when it comes to the type flag:  find $dir_name $(printf "! -name %s " $(cat $exclude_file))   Is there a way I can do it or will I need to create the entire list and then work through it removing ones that partially match ones in the exclude directory. How can I make sharp geometric 3d models look more realistic? I'm making a scene in Blender with manufactured mechanical and electrical objects - cylinders, metal objects and so forth. I want to make these look real, be fully present with a sense of mass and substance.  3DCG has a tendency to make everything very sharply geometric, often looking mathematical and artificial. In other scenes, some organic curves, normal maps or particle systems would help make object look real. Like for example, making a simple plastic dog model look more believable, one can add more vertices for better definition, add texture layer, add fur etc.  My scene shows clean resistors, wires, metal strips and such, all sharply geometric. It's tricky to find ways to make the result less mathematical and more substantial, realistic and interesting to the eye.  What are some effective ways to add realism to these objects? Construct a command by putting a string into a tty I managed to do this  echo -n "command" &gt; /dev/tty1  The letters appear, and the cursor moves, but they are "ghosts" – if you hit Enter, nothing happens (they are not in stdin).  Edit:  In the middle of the below screenshot, you see why I see the use of this. (The line with a red caption, right below the line with a yellow caption.) As it is now, you are not really "editing" the note text; you are just asked to write a new text, which will replace the text of the note you are (not really) editing. Thus, I thought it could be remedied by simply pasting the old text into the tty: if the user hits enter, no modification is made. (This program is in Perl/MySQL, but I thought it would be more interesting to ask for a general solution than "how do I do this in Perl".)    Edit 2:  Here is the Perl code, that uses the C code below (works exactly as intended), as well as a new screenshot – hopefully this will clarify things beyond doubt :) Again, look at the middle of the screenshot, where the edit is made to the note text - this time around, the old text is there, for example if you just wanted to fix a typo, you won't have to retype the entire note text.  my $edit_note_text = $edit_note_data[2]; print BOLD, RED, " new text: ", RESET; system("writevt /dev/tty \"$edit_note_text\""); my $new_text = &lt;$in&gt;; $new_text = fix_input($new_text); my $set_text = "UPDATE notes SET note = \"$new_text\" WHERE id = $edit_note_id"; $db-&gt;do($set_text); copy a certain range of one sheet to a certain specifed cell in other sheet Does a percentage require a singular or plural verb, for example, do we say ten percent "go" or "goes"?