Over 100 years, Methane has a  34 times bigger than Carbon dioxide. Over 20 years, it's even 86 times bigger. How does one arrive at these numbers?  Looking at the following graphic doesn't help either, as the area for Methane barely covers the left margin of the upgoing thermal radiation and Carbon dioxide is at the right margin. The area under the absorption curve for Carbon dioxide is definitely bigger than the one for Methane.    Source:   So what makes Methane a more effective greenhouse gas?
Methane’s absorption bands are centered at 3.2 and 7.2 microns -- far off the peak of the Planck spectrum for a 290 K blackbody near 16 microns.  Moreover, its absorption bands overlap with the water absorption region.  So why is methane considered a stronger greenhouse gas than carbon dioxide, which has an absorption band at 15 microns?
Nicely force 66 characters per line How do I clear Bash's cache of paths to executables? When I execute a program without specifying the full path to the executable, and Bash must search the directories in $PATH to find the binary, it seems that Bash remembers the path in some sort of cache. For example, I installed a build of Subversion from source to /usr/local, then typed svnsync help at the Bash prompt. Bash located the binary /usr/local/bin/svnsync for "svnsync" and executed it. Then when I deleted the installation of Subversion in /usr/local and re-ran svnsync help, Bash responds:  bash: /usr/local/bin/svnsync: No such file or directory   But, when I start a new instance of Bash, it finds and executes /usr/bin/svnsync.  How do I clear the cache of paths to executables? Penguin Brainteaser : 321-avoiding permutations There are $k$ penguins, $k\ge 3$. They are all different heights. How many ways are there to order the penguins in a line, left to right, so that we cannot find any three that are arranged tallest to shortest (in left to right order)? The penguin triples do not have have to be adjacent.  This problem is courtesy of someone I know only as "DaMancha." Prove $\lim_{n\to\infty} \frac{a_n}{n}$ exists for positive sequence where $a_{n+m} \leq a_n + a_m$ Let $\{a_n\}_{n=1}^\infty$ be a positive sequence of real numbers such that $a_{n+m} \leq a_n + a_m.$  Prove that $\lim_{n\to\infty} \frac{a_n}{n}$ exists by showing that $\lim_{n\to\infty} \frac{a_n}{n} = \inf_{n \geq 1} \frac{a_n}{n}.$   A similar question has been posted previously, see  , and I have found that this is the general result of "Fekete's Subadditive Lemma" for sequences, but I am unhappy with the few proofs I've seen.  Perhaps the clearest one I have found is  , but this seems a bit tricky for what is expected on this qualifier question.  We are given a hint "treat $\liminf$ and $\limsup$ separately".  Does anyone know of a more direct way to show that this limit exists? Find angle UFO in the picture attached I sent this problem to Presh Talwalkar who suggested me to send it to this site. I tried many things but was not able to find the correct solution.   I made various segments trying to get an equilateral triangle similar to the Russian triangle problem, but no success.  I also tried to flip the triangle UFO over side NO but again no success.   I tried to find like triangles, but not enough.  Could you please give me a hint?   Thanks, R. de Souza We have a webservice that our application uses and the developers require https connections to the webservice.  Since this is an internal webservice would you use a self signed cert? What's with those who ask a question, but don't ever seem to come back to add requested info? On stackoverflow, there seem to be quite a few programmers who ask a question, usually with one line like:  "How do I release memory after memory warning? My app crashes. Thanks and welcome for reply."   And a bunch of us will ask questions like   what platform? give us some more detail about the crash.   Weeks will go by and the original poster never adds any more details.  In the meantime, some respondents go ahead and answer the question thoroughly, covering possible platforms/scenarios, etc.  Of course no answer is ever selected by the OP.  Then the OP shows up again, and asks another question, sometimes its the same question asked differently, sometimes not.    What is going on here?  Do they have one chance every so often to get a query out on the Internet and they get through and they post and then they can't get back?  Or are they forgetful, since they are posting the same question to tens or hundreds of sites?    I'm just curious.  Seems like they shoot themselves in the foot when they have a captive audience waiting for more details of their problem, yet they never provide those details. Maximum number of edges in a bipartite graph Prove that for a bipartite graph $G$ on $n$ vertices the number of edges in $G$ is at most $\frac{n^2}{4}$.     I used induction on $n$.    Induction hypothesis: Suppose for a bipartite graph with less than $n$ vertices the result holds true.    Now take a bipartite graph on $n$ vertices.Let $x,y$ be two vertices in $G$ where an edge exist between $x$ and $y$. Now remove these two vertices from $G$ and consider this graph $G'$. $G'$ has at most ${(n-2)^2}\over4$. Add these two vertices back.  Then the number of edges $G$ can have is at most    $$|E(G')|+d(x)+d(y)-1$$   My question is in my proof I took $d(x) + d(y) \le n$, where $d(x)$ denotes the degree of vertex $x$.  Can I consider $d(x)+d(y) \leq n$? I thought the maximum number of edges is obtained at the situation $K_{\frac n 2,\frac n 2}$ When for the first time A new question I answer This haiku appears:     Little slab of meat   In a wash of clear jelly   Now I heat the pan   Such a message is Very strange; is anyone Seeing the same thing?  Have not seen again. Came and went like the wind does! Why I am so blessed? "The pair was ..." or "the pair were ..." I currently have an ec2 &quot;t2.nano&quot; instance up and running. I would like to switch to a &quot;t2.micro&quot;. In order to do that, I need to stop the instance. But I would lose my IPv4 address in the process. And I do not want that (because I have several ssh tunnels up and running from rasps in the wild that are currently hard coded to connect to this IPv4 address). I decided to create an Elastic IP address. But I understand that by creating an Elastic IP address and assigning it to my current ec2 instance, I would lose my current IPv4 address too. Is it possible to create an Elastic IP address from the current IPv4 address of my ec2 instance? If so, how can I do this operation? 16.04 Upgrade: Failed to fetch Empty files can't be valid archives Is it feasible to compile Python to machine code? Let $F$ be a field and $x\in F$. If $x=-x$ and $1\neq -1$, then $$0=\frac{x+x}{1+1}=\frac{1+1}{1+1}x=x.$$ This means that the statement in the title is true if and only if $1\neq -1$. But how do we know that $1\neq -1$ for an arbitary field? Electrical potential energy stored in vacumm for a single point charge? I have come to know the electrostatic potential energy in vacuum is given by $${\frac{1}{2}} \epsilon_0\int d^3x {E^2} $$ and this energy  is due to the mutual electrostatic coulomb potential energy. So only a single point charge in space also contributes to some electrostatic potential energy according to $${\frac{1}{2}} \epsilon_0 \int d^3x {E^2} $$  as due to a single point charge also we have an electric field at every point in space. Now I am not getting it physically, why should there be any Coulomb energy in this case as there is no other charge to provide the electrostatic coulomb potential energy? Is it possible to increase Output Field Name length beyond 10 characters? When creating a new Column, the default value for the length of the name is 10. Using the Field Calculator via the Model Builder, I want to include the names of regional areas into the columns which has more than 10 characters.  Can the length of the Output Field Name be increased? Dynamic loading of python modules Why are cancer rates low in large animals? Large animals generally have more cells and live longer than smaller animals. For example,  live up to 200 years and weigh up to 100 tonnes, as opposed to humans (living ~ and weigh ~) and  (10–25 g, &lt;1 year in the wild). Hence, whales have an immense number of cells and those cells are subjected to environmental carcinogenic influences (chemicals, UV) for a longer period of time.   Cancer is caused by random mutations and those random mutations are basically stochastic processes. Given their long life span and larger number of cells, shouldn't larger animals have a substantially higher chance to develop cancer? In fact, story goes that bowhead whales in fact only , and less so compared to humans? Can a free particle absorb/emit photons? Conditionals in English are usually formed by using if with normal word order; but for the three past (subjunctive) forms were, should, and had, it is also possible to express the conditional through subject–auxiliary inversion alone, with no if in the conditional clause.  Does forming conditionals in this manner differ semantically from if-conditionals? Is some aspect of the conditional statement or the conditionality emphasised more in one version than in the other? Or are there differences in how and when they are used? Or are they simply completely interchangeable?  For example:     If I were you, I would try it again   Were I you, I would try it again      If I had seen it, I would have told you   Had I seen it, I would have told you      If you should drink, don’t get behind the wheel   Should you drink, don’t get behind the wheel