mooeypoo

Neveos, this isn't censorship. Censorship would've been closing this thread outright, which wasn't done. We are giving you all the available tools and patience we can bear so you have the opportunity to actually give us some substance,rather than tangential rants and mythos. Science works by evidence, Neveos, not be what seems to make sense to you. The current theories, as was pointed out to you many times in the thread, are not only "making sense" but they also have the power of having evidence on their side and the power of prediction. That is, using the ucrrent theory we can successfully predict how things will behave. For us to accept your theory, you must show us this step. For three pages and 50 posts,you haven't. Don't insult us by claiming censorship when this thread is clearly letting you continue ranting for 50 posts without a shred of actual valid science. You're in a science forum, not in your personal rant blog. It's time you provide some evidence and actual science. Remember, we didn't invite you to lecture, you chose to come to us, and by choosing that, you agreed to follow our rules. Maybe you should go over them. ~moo

Seeing as this is an unrelated subject to that of the original thread, and also is beyond mainstream physics, it was moved to speculation forum.

Alright, trying again, then: [math]E=10mJoule = 10*10^{-9}J=6.2*10^{9}eV[/math] [math]t=100fs = 10^{-13}s[/math] [math]A=1cm=0.01m[/math] So: [math]P=\frac{E}{\triangle t} = \frac{6.3*10^{9}eV}{10^{-13}s}=6.2*10^{22}eV/s[/math] [math]\frac{P}{A}=\frac{E_0^2}{2\mu c}[/math] So: [math]\frac{6.2*10^{22}}{\pi *10^{-4}}=\frac{E_0^2}{2\mu c}[/math] [math]E_0^2=1.24*10^{27}\frac{\mu c}{\pi}[/math] [math]E_0=3.52*10^{13}\sqrt{\frac{\mu c}{\pi}}[/math] And so, to find the magnetic field: [math]B=\frac{1}{c}E_0=\frac{3.52*10^{13}}{c}\sqrt{\frac{\mu c}{\pi}}=\frac{3.52*10^{13}}{3*10^8}\sqrt{\frac{\mu c}{\pi}}=1.2*10^5\sqrt{\frac{\mu c}{\pi}}[/math] Is that right? seems right... I hope...

omg omg it's an administrator! you must be in real trouble NOW.... runnnnnnn! Anyhoo. I think it's time to tell us the answer or at least a hidden version of it, or a hint towards what you mean, at least, seeing as it doesn't seem many people understand where you're going with this... is this a logic riddle? a scientific anomaly? a brainteaser? a prediction? ;-)

These are two different servers (IRC and WEB) so it's not the same problem. Whatever the problem is, the IRC server is now semi-operational (routing to another IRC subdomain) and hopefully will come back online soon.

Ah, milli, I thought Mega for some reason.. you're right, Mega should've been Mj and not mj. Bah. Okay, other than that, I assume it's a Gaussian beam just because that's the usual pulse we're dealing with. I don't know if I understand where the time effect comes in, though, swansont? where do I get it mathematically into the equations? How would it affect what I did..? In other words, what I did until now (forget the milli/mega for a second) is right if this is a continous wave but wrong for a pulse? I'm trying to understand the methods so I can understand which to pick and when.

Hey guys, I missed class the other day and we have hw that are going to be in the exam we have this week. I'm confused and stumped and I can't find info online. There's a strong possibility I'm overcomplicating stuff because I'm stressing myself out, but.. well.. that's why I'm trying to get help here. Naturally, I'm not looking for the solution alone, but since I missed the class, I''m not entirely sure I know if I'm doing it right. Also, the professor doesn't go by the book, so it makes things a lot harder. So, here's the first question I'm in trouble with: Find the electric ([math]E_0[/math]) (in V/cm) and magnetic (B) (in gauss) fields for 10 mjoule pulse of 100 fs duration focused to 1 cm spot. So, here's what I think (absolutely not sure, tho, again, I missed class): [math]t=100fs[/math] [math]Area=1 cm^2[/math] [math]P=10 \text{mjoule} = 10^7 \text{joule} = 6.2*10^{25} eV[/math] And I start with the wave equation: [math]E=E_0 \exp{(100\omega - kz)}[/math] And [math]\frac{P}{\text{Area}}= \frac{E_0^2}{2 \mu v}[/math] [math]\frac{6.2*10^{25} eV}{1}= \frac{E_0^2}{2 \mu c}[/math] [math]6.2*10^{25}\mu c=E_0^2[/math] [math]E_0=\sqrt{6.2*10^{25}\mu c}[/math] Is that right? I'm not sure also about my units, and also, where is the time info (the fact it's a 100fs pulse) fit into this? And that would mean that to find B, I'm still using [math]B=\frac{1}{c}E_0 = \frac{\sqrt{6.2*10^{25}\mu c}}{c}[/math] Is that right? Thanks in advance, guys, and... well.. I probably will post a few more of these. ~moo

my feathers weren't ruffled, and my post really wasn't done in my capacity as a moderator.. it was my "two cents". I might be a moderator, but I'm a member of the forum, too

"why wouldn't we" because they might be wrong. The idea they came to Earth doesn't mean they know everything, it just means they know how to travel. But seriously, we're going to need something much better than an Alien's "word for it". For that matter, if they know so much better, they'd have no problem proving it. And when they do, we can talk about it. ~moo

That might be, but those things are falsifiable and testable. For a phenomenon to be considered scientific, it must be both falsifiable and testable. If a phenomenon is claimed to exist but there's no way to test for it and it is explained by a set of loosely fitting explanations (that render it effectively unfalsifiable) it is not scientific. Where' the falsifiability of the claim, for one?

Party pooper. Neg rep! Just kidding! ... Probably..

I was testing you. ... yay!

Actually, that's inaccurate. Jill was allowed entry into the Politics thread after her 50th post and with a good reputation. She posted a thread asking why she can't get in at the DAY of achieving those goals.. it just took the system a bit longer to "process" it. Second, even if the above wasn't true and Jill would have asked to post in the Politics thread, we - the moderators - would have examined her other posts, and make a decision particularly for her. We did that before with other members that specifically asked to get into Politics. We sometimes allowed them even "before" the "official" time and sometimes we didn't allow for it, for various reasons. The point is that we came up with this specific regulation for a reason; the forum didn't always have it, and we were suffering over it (and not just mods). People came for "hit and run" posts, trolling, and derailing the threads for no other reason than to just yell and scream. And since we define this forum as primarily scientific, we decided that the politics forum is, as far as we're concerned, a "bonus" feature. It's by far not the main feature, and it shouldn't be the reason people join us. But since people like talking and debating those issues, it exists. It really isn't some attempt to hold people's opinions back, jackson. We had a few examples that prove you wrong, actually, I just don't remmeber them off hand. There were a few relatively new members that asked to get into the Politics forum and were granted the request. The others just had to wait patiently for the (seriously not that horrible) request of 50 posts of good quality. If people give you negative rating for your opinions, that shouldn't happen, and if that happens repeatedly, you should let us know. As it is, though, the negative rep is USUALLY an indicator of a poster's attitude and method of argument. Use of logical fallacies, disrespect, etc. That's a pretty good measure of knowing we don't want that person involved in threads that are ALREADY a delicate balance of emotion and fact. It's also the membership and staff's decision, as maintainers and founders of this forum, to make up the rules and "spirit" of where this forum is going. The forum was decided to be SCIENTIFIC in nature, and not political. The reason the political forum was left open when the Religion forum was shut down is because of the huge demand for it from existing members. Otherwise, it likely would have been shut down too. That's not the goal, nor is it a proportional response to what is likely a minor "offense" and therefore is entirely irrelevant. If DS comes back and corrects his ways, his red dot will gradually turn to a green dot, as both moderators (some of which hold a relatively large rep-power) and members will rep him up. This happened before, by the way. We've had a few members that started off on the wrong foot (I will leave their names confidential unless they want to expose themselves) but corrected their ways and some even became quite the important pillars of the community. These happen, but they don't happen to people who disrespect others, curse, troll, hijack threads or are generally being annoying. If you think that's "punishment" then you're right. We don't want those who act this way and don't improve their ways to stay here, plain and simple. That's why we have rules. If they change, their reputation changes (proven, it happened) if they don't change, they might as well leave. Really? I mean.. did you look at the posts for which this specific poster was suspended or did you just assume it was the post you've seen in this thread? You might be surprised. We aren't blood-thirsty suspension-hungry trigger-happy moderators, you know; We usually give quite the large leeway to any member - sometimes a bit too much leeway, it can be argued - and encourage them to correct their ways. A suspension and/or ban only comes after it is clear they either need a break or (as it seemed to have been in this case) when it's clear that the ranting, frustration and disrespect are flowing rapidly everywhere in multiple posting. Judge not what you do not know, eh? That's an interesting endeavor, we might end up looking at those points. But the bigger and more important statistics here is that the fear of "taking advantage of the neg-rep" is shown to be exaggerated. A bit over 2% of all reputation given was negative. That's it. That's the big deal? That's the huge "OMG PEOPLE ARE GOING TO TAKE ADVANTAGE OF IT" scare? really, guys, we're losing sense of proportion here. Just like positive rep exists to let someone know that a specific post is appreciated, a negative rep is to let someone know that a specific post is NOT appreciated. That simple. No one is banned for having low reputation, and there are a number of ways to reduce the chance of a member being attacked for nothing; And the bottom line is quite clear -- so far, those with low rep deserved it, and those with some offenses don't have THAT low of a rep. C'mon now. Let's not blow this out of proportion, shall we? ~moo

I disagree. Those who clearly deserve to have their neg-rep not count seem to already have their neg-rep not count (as you noticed yourself). The neg-rep is a good way of telling posters that certain attitudes or behaviors aren't appreciated by the community (or by a person, in which case it counts less) without making personal attacks or irrelevant debates spill into the actual thread. If you see someone that abuses the system (and it won't be hard to notice), then you should report it to the staff, in which case we'll examine it and deal with it, but I don't think this will happen often. What's more likely to happen is that people will get positive reputation for great posts and some negative reputation when they were over the line or when their posts aren't up to par, which will encourage everyone to add that much more quality to our posting. I am not sure, but I don't think there's a whole lot of neg-rep going on the forum since the system was opened. Most people seem responsible enough to not give it for nothing, and not abuse it, and those who aren't usually don't have any rep-power anyways. Also, this is a science forum and not a politics forum. The politics thread is a sort of an addition, an answer to some of the members' requests, but as you probably can see from the discussions there, it's VERY different than other discussions in the forum. In the past, we've noticed new members that would sign up and post ONLY on the politics thread - sometimes just stay there to troll or yell/scream their agendas - and clearly having no interest in science, but rather interest in pounding their political agenda. We really don't think the politics forum should be abused like that, so we decided that only members of the forum could use it. Naturally, we had to find some way of discerning "members" from one-time-posters who's sole desire was to argue politcs, so we set up the scale on the post-count and reputation. ~moo

dr.syntax has been suspended for a week for repeated trolling, disrespect and continuous thread hijacking.

Ah! I thought of that, though, and infinity, no matter what I multiply, add or subtract to it, is still infinity. Same goes with negative inifinity.. so I figured the limits are okay to remain the same. ..wait, what? Infinity + a constant is not infinity?........ really?...... what... is it? I'm not sure I understood the last bit (b), but I also never studied this. Where can I read a bit about these concepts? You know, I already complained about it to my physics advisor (and to the Department Chair) but this is ridiculous. As a physics undergrad, I took math courses along with Engineers in courses that seemed to be tailored for Engineers. It might sound pretentious, but this is a serious drawback. Engineering undergrads' attitude towards math is to memorize the formula and use it when needed, as opposed to actually going over the (yeah, sometimes complex, boohoo) method of deriving the formula so that when I encounter something that has no formula, I can actually deal with it. I don't think Engineering students know about the concept that sometimes things are.. like.. new.. and don't have formula.. and you need to actually use your logic and math skills to handle them.. gee. Now that I go over actual Physics, in the course and in my research project I have to study most of the math myself. It's just annoying as hell, I feel so math-ignorant for a physics girl. Anyhoo, I had to rant. ~moo

Is this for homework, jamesgunasekera, or is this for some statistical poll? Seems to use "personally" a lot

My u-substitution won't work here, D H? [math]u=t+\frac{i\omega\triangle t}{2\alpha}[/math] [math]du=dt[/math] And therefore: [math] \exp{\left( \frac{\omega^2}{4\alpha} \right) } \int \exp{\left( \frac{-\alpha}{\triangle t^2} u^2 \right) }du =\exp{\left( \frac{\omega^2}{4\alpha} \right) }\left( \sqrt{\frac{\pi \triangle t^2}{\alpha}} \right) [/math] ? p.s: This is for a physics class.. specifically Optics.

... that's a definite integral???... uh.. really? So.. uhm Okay, so: [math] =\exp{\frac{\omega^2}{4\alpha}}\left( \sqrt{\frac{\pi \triangle t^2}{\alpha}} \right) [/math] And since [math]\omega = 2\pi \nu[/math] So: [math] =\exp{\frac{\pi^2\nu^2}{\alpha}}\left( \sqrt{\frac{\pi \triangle t^2}{\alpha}} \right) [/math] And my initial alpha represented the constant 4ln2, so my final answer: [math] I(\nu)=\sqrt{\frac{\pi \triangle t^2}{4ln2}} \exp{\left( \frac{\pi^2\nu^2}{4ln2} \right)} [/math] Which is ugly, but should work. Thanks Merged post follows: Consecutive posts mergedAnd now, just to verify, the next problem section asks to find [math]\triangle \nu \triangle t = 0.44[/math] Which is the gaussian value. So to find the [math]\triangle t[/math] I am looking for I(t)=1/2 for the FWHM. [math]I(t)=1/2=\exp{(\frac{-4ln2t^2}{\triangle t^2})}[/math] [math]0-ln2=-\frac{4ln2t^2}{\triangle t^2}[/math] [math]t^2=\frac{\triangle t^2}{4}[/math] [math]t=\frac{\triangle t}{2}[/math] [math]\triangle t=\frac{t}{2}[/math] Which is the obvious solution.. And for [math]\triangle \nu[/math] I am looking for I(v)=1/2: [math]I(\nu)=1/2=\sqrt{\frac{\pi \triangle t^2}{4ln2}}\exp{(\frac{\pi^2\nu^2}{4ln2})}[/math] [math]\frac{\sqrt{ln2}}{\sqrt{\pi}\triangle t}=\exp{(\frac{\pi^2\nu^2}{4ln2})}[/math] [math]ln \left( \frac{\sqrt{ln2}}{\sqrt{\pi}\triangle t} \right)=\frac{\pi^2\nu^2}{4ln2}[/math] [math]\frac{4ln2}{\pi^2} ln \left( \frac{\sqrt{ln2}}{\sqrt{\pi}\triangle t} \right)=\nu^2[/math] [math]\nu = \frac{2\sqrt{ln2}}{\pi}\sqrt{ln\left( \frac{\sqrt{ln2}}{\sqrt{\pi} \triangle t} \right)}[/math] Logically, delta-nu would be double the above. And so, technically, I'm supposed to show that [math] \triangle \nu \triangle t = 0.44 [/math] Which is a hugeomongous headache, but should be the right method... I think.

omg i feel silly, I didn't notice the fact it's a constant!!! bah. And yes, I know i^2=-1, I forgot to change it. Here's what I have, then: [math] \int \frac{ \exp{ \frac{-\alpha}{\triangle t^2} ( t + \frac{i\omega \triangle t^2 }{\alpha} )^2 }} {\exp{\frac{i^2\omega^2}{4\alpha}} } dt = \exp{\frac{\omega^2}{4\alpha}} \int \exp{\frac{-\alpha}{\triangle t^2} \left( t+\frac{i\omega\triangle t}{2\alpha} \right) ^2 } dt [/math] BTW, <sigh> if you go back to the initial equation, alpha was negative, and I seem to have neglected that at some point. It's back on the equation above, though. In any case, I looked at the table of integrals and I can't really find a way to solve this in the indefinite integral. I was thinking of continuing with a u substitution: [math]u=t+\frac{i\omega\triangle t}{2\alpha}[/math] [math]du=dt[/math] And therefore: [math] \exp{\left( \frac{\omega^2}{4\alpha} \right) } \int \exp{\left( \frac{-\alpha}{\triangle t^2} u^2 \right) }du= [/math] But now what? I went over the table of exponential integrals (the professor actually suggests we do this in the hw sheet) and the only solution I can see is if my integral is definite, which it shouldn't be, because it's a fourier transform. There's also this: But what is this "error function"? Is this really it? It's the first time I see anything like that, so I'm not sure. Gah!?

Oh, shoot, you're right, sorry, yes all integrals should end with "dt". Sorry 'bout that. And... hm. Okay... trying now. Merged post follows: Consecutive posts mergedOkay, so I have one more step: [math]\int \exp{\frac{\alpha}{\triangle t^2} \left[ \left(t + \frac{i\omega \triangle t^2 }{\alpha} \right)^2- (\frac{i\omega \triangle t}{2\alpha})^2 \right]} dt = \int \exp{\left[ \frac{\alpha}{\triangle t^2} \left(t + \frac{i\omega \triangle t^2 }{\alpha} \right)^2 - \frac{i^2\omega^2}{4\alpha} \right]} dt [/math] And then "reversing" the process: [math] \int \frac{ \exp{ \frac{\alpha}{\triangle t^2} ( t + \frac{i\omega \triangle t^2 }{\alpha} )^2 }} {\exp{\frac{i^2\omega^2}{4\alpha}} } dt[/math] But.. how does that help me? it seems to make it more complicated to solve, not easier...

Hey guys, I'm working on a fourier transform and got stuck in a stage where I think I'm supposed to complete the square .. but.. I don't manage to do it. Here's what I have: [math]\int \exp{(\frac{-\alpha t^2}{\triangle t^2})} \exp{(-i\omega t)}=\int \exp{-(\frac{\alpha t^2}{\triangle t^2}+i\omega t)}[/math] And so from this point I want to complete the square so I can continue to solve. Here's how I started: [math]\frac{\alpha}{\triangle t^2}\left( t^2 + \frac{i\omega \triangle t^2}{\alpha}t \right) = \frac{\alpha}{\triangle t^2}\left( t^2 + \frac{i\omega \triangle t^2}{\alpha}t + (\frac{i\omega \triangle t}{2\alpha})^2 - (\frac{i\omega \triangle t}{2\alpha})^2 \right) [/math] [math]= \frac{\alpha}{\triangle t^2} \left[ \left(t + \frac{i\omega \triangle t^2 }{\alpha} \right)^2- (\frac{i\omega \triangle t}{2\alpha})^2 \right] [/math] So that's what I have now in the exponent: [math]\int \exp{\frac{\alpha}{\triangle t^2} \left[ \left(t + \frac{i\omega \triangle t^2 }{\alpha} \right)^2- (\frac{i\omega \triangle t}{2\alpha})^2 \right]}=[/math] But.. now what? Our professor told us that the way to go from the first stage is to complete the square and use an integral table to continue, but I don't see how that helps me... What did I do wrong? Any ideas? Thanks!! ~moo p.s-- i accidentally wrote t instead of t^2 in the first instance, which made the first equation wrong.. I fixed it now. The equation is right, the missing square was a typo.

Right, okay, you weren't asked to bring definitive evidence, or even non-definintive evidence, you were asked to answer the criticism about your hypothesis. The criticism that shows your hypothesis to be nonfalsifiable and allow too much room for selective data and confirmation bias. If your hypothesis is nonfalsifiable or allows for too much room for confirmation bias or selective data, it's not scientific. We've been over this, though. And you still didn't answer the claims. ~moo

Fine, you 'got him'. Can you relate to the criticism, now, though? I'm quite intrigued to see how you thought these problems through, seeing as some of them seem to make this claim unfalsifiable (as was pointed out multiple times). There are 148 posts in teh thread, Edmond. Ignoring the ones where we put up our criticism doesn't mean the criticism doesn't exist.. We pointed out a few times how your claim leaves too much room for bias, and how it seems to be unfalsifiable. Can you answer these?

dr.syntax, you were shown ample counter-claims and were given the time to show actual peer reviewed science behind your claim. You failed to do that, and the thread was closed. Reopening a closed thread is against the rules, dr.syntax. It might be in your best interest to go over them. If and when you have an actual peer reviewed evidence in favour of this claim, the thread might be reopened. As of now, you're strongly encouraged to go over the rules, not reopen a previously closed thread, and start talking valid science rather than unsupported claims. ~moo