User talk:The snare

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[edit] Welcome!

Hello, The snare, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are a few good links for newcomers:

I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or place {{helpme}} on your talk page and someone will show up shortly to answer your questions. Again, welcome! --Srleffler 05:31, 23 April 2006 (UTC)

I reversed your edit to candela, because the term "brightness" should be avoided as a quantitative description of light. It leads to confusion, since the term can equally well mean any of luminous flux, luminous intensity, luminous emittance, radiant intensity, radiance, etc.--Srleffler 05:31, 23 April 2006 (UTC)

The snare-Yeah, sorry, just thought perhaps it would be more simple, I'm not a scientist, just sometimes a lot of articles are hard to understand if they aren't written plain English. But I guess your right, a lot of things require pre-requistites,

Anyway, I was just wondering perhaps, how many candelas it would take to blind you, either temporarily or permanently, and what exactly happens, the rods and cones just are stunned by the huge input of light, or just plain destroyed and cease to function if they are overloaded.

I also heard there's no limit to the brightness of light or the loudness of sound (though I had previously heard otherwise that a sonic boom is loudest audible phenomenon that could happen) in the latter case would it be quite literally possible to make a sound in the air so loud that whole world could hear it? —The preceding unsigned comment was added by The snare (talk • contribs).

Well, the amount of light it would take to blind you would probably be measured either in cd/m2 or in W·sr-1·m-2, since it's probably the luminance or the radiance of light that would determine whether a source is "bright" enough to blind someone. This confusion of units is exactly why the term "brightness" needs to be avoided. The actual amount of light needed to cause blindness would also depend on the wavelength (or mixture of wavelengths) present. Coherence of the light is also a factor. You can be blinded by a relatively low-power laser, because the laser's beam can be focused by the lens of your eye to a very small spot on the retina, producing a lot of damage very quickly.
I recall a discussion of the maximum loudness of sound at talk:decibel a while ago. There is a maximum above which it may not be appropriate to keep calling it "sound". A sound wave consists of a moving pattern of more and less dense regions of air. The more intense the sound wave, the greater the pressure extremes. For a sufficiently intense sound wave, the less dense (lower pressure) regions of air would have to be a vacuum. The pressure can't get lower than that. A wave this intense would distort greatly as it travelled, since the increases and decreases in pressure can't be uniform. More intense "sound waves" do travel, though, and have properties distinct from ordinary sound. Shock waves are an example of this. In principle, one could imagine a shock wave that would vaporize the whole world, so yes I'm pretty sure it's possible in principle to make a "sound" so loud that the whole world could hear it. The amount of energy required would be enormous, though. The listing at Makeitlouder.com gives examples of some things that are louder than a sonic boom. Note that your eardrums rupture at around 195 dB, and that a shock wave of around 200 dB can kill you outright.
For light, there is no maximum other than the limits of your source. There is a limit, though, to how much you can concentrate the light from any given source. Light from a given source has a certain luminance, which cannot be increased by any optics. If you imagine a "beam" of light, it has a certain diameter but it also spreads out as it travels. Luminance takes both of these things into account. If you use a lens to focus the beam to a small spot, it spreads out faster after it passes that focus.
While there is no maximum intensity for light in general, there is a maximum intensity for light in air. A sufficiently intense beam will ionize the air, producing a plasma, which reflects light. --Srleffler 06:47, 25 April 2006 (UTC)

[edit] More questions and answers

Yes, your talk page is visible to anyone. You also have a user page where you can say a bit about yourself and your interests.

Fusion only works up to iron. The elements heavier than iron are formed only in supernovas. As I recall, the supernova produces an extremely intense wave of neutron bombardment. The neutrons are absorbed by heavy elements, which then beta decay into higher elements on the periodic table. These then absorb neutrons and the process repeats. You get a big chain reaction where, in minutes or hours, huge quantities of iron, etc., are converted into heavier elements. There are several different chain reaction sequences that occur at different rates. The observed abundances of the different elements agree with what one would expect from the rates of the different reactions, so this model is pretty solidly established. In particular, some isotopes can't be produced by any of the chain reactions. Those isotopes tend to be rare unless they are produced by some other process. There's an article on this at Supernova nucleosynthesis, but it doesn't look very good and I see some things there that may not be factually correct. (I'm not an expert on this area of physics.)

The "spin" referred to in the context of Bell's theorem (and other quantum mechanics of subatomic particles) is not really a physical rotation. It is an intrinsic property of many particles that has mathematical properties similar to those of rotating objects. Initially, it was thought that electrons, etc. were like little billiard balls that could be spinning. It was later understood that this is not the case, but the name stuck. Different particles have different spin states that they are allowed to have. For example, an electron or a photon (a particle of light) can only have two spin states. We call these (arbitrarily) "up" and "down". It's not clear what exactly this means physically, but there are various ways to measure the spin of a particle or "flip" it from one spin to another.

Back to Bell's inequality: it isn't possible (we think) to send information instantly using this property, because you don't control the spin. You create two particles from one in such a way that one has spin "up" and the other has spin "down", but you don't know which is which and in fact the particles don't know which is which until they are measured (this can be proven, and has been). At the moment one of the particles' spins is measured, the other particle will "instantly" have the opposite spin, no matter how far away it is. But you can't force the particle to have the spin you want. It's random. Someone looking at the other particle knows that your particle had the opposite spin to hers, but there is no way to send information since you can't control which spin your particle would have. If you change the spin of your particle, you break the connection between them. Also, measuring the particle breaks the connection, so you only get to do this trick once per particle.

Yes, this is a pretty bizarre result. This effect was predicted years before anyone observed it, and the prediction was used in an argument that quantum mechanics couldn't be completely right (Einstein was one of the people making that argument). It turns out, though, that the effect is observed just as predicted. One can show that this result proves that one of several important assumptions of physics is wrong, but we aren't sure yet which one it is. It is usually assumed that the incorrect assumption is "hidden variables", the idea that we could in principle come up with a better theory than quantum mechanics, which has additional variables to describe the particles that are "hidden" from us under quantum mechanics. This is felt to be more palatable than the best-known alternative: giving up the idea of locality, that says that particles can't transmit effects from one to another at faster than the speed of light. It's not actually clear which of these assumptions is wrong.--Srleffler 05:40, 27 April 2006 (UTC)

[edit] Thanks Again

Well thanks, and it's says your a physicist, are you professor, or just work doing research, etc?


I wasn't vandalizing, there's a lot of evidence that the Q aren't omnipotent. —The preceding unsigned comment was added by The snare (talk • contribs).

Alright, first off:
Please remember to sign all of your posts on talk pages. Typing four tildes after your comment ( ~~~~ ) will insert a signature showing your username and a date/time stamp, which is very helpful.
Secondly, I understand your point, but userpages are about users, not for commenting. Talk pages were created for this purpose.
Now that the warnings are out of the way: If you have proof, why not post it on the article's talk page? That's what the talk page is for. :) Post something like "I posted [insert what you posted here] because [insert reason here]. I was reverted because it looked like vandalism. The proof it is not vandalism is [insert reason here].". Make sense? I thought it did. — nathanrdotcom (Got something to say? Say it.) 03:26, 15 May 2006 (UTC)

I don't understand, why can't I post the Q aren't omnipotent if they're aren't omnipotent, it's a fact, which is revealed in the episodes, why should I put it on the talk page? if it's true, it's true, and it is The proof it's not vandalism it is in the episodes.I've never had a problem posting a FACT to a wikipedia, especially if it's true, sheesh The snare 04:39, 15 May 2006 (UTC)

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