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Physics, Astronomy & Cosmology / Why has Jupiters southern belt disappeared?

« on: 17/10/2010 23:22:41 »

Belt singular?  What is there in its place?

You'd need more than just high power binoculars, or a small telescope to see the different weather belts on Jupiter.  You can certainly pick out quite a few of the Jovian moons through a 10x pair of binoculars but you're still just talking points of light.  Even if you were to have a 100x pair of binoculars you'd not be able to see the weather belts (and being 100x magnification you'd have to use them with a stand/tripod because you certainly wouldn't be able to hold them steady in your hands).

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General Science / Why can't I block out low frequency sounds as easily as high frequencies?

« on: 17/10/2010 23:05:34 »

Geezer: yes, the impedance of the driver will vary with frequency, but not so far as to take into completely different realms of voltage and current delivery.

Lee - Take a butcher's at this. It may change your opinion. http://users.ece.gatech.edu/mleach/papers/vcinduc.pdf

Geez: I'm simply not prepared to wade through eight pages of an academical paper in search of what, exactly?

C'mon - don't expect me to put all the effort into proving myself wrong - that's your job.  And I'm not saying that the paper you referred to is not relevant, but just pick out and quote the bit of it that is relevant to this thread, and then give the link to the entire paper so I can verify it.

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The Environment / Re: Global Warming - Are we too late to reverse the course?

« on: 17/10/2010 22:52:08 »

The premise of this thread is intrinsically flawed: it portrays unproven speculation as fact, and is hence worthless.

(Now, at this point, I need to decide whether to offer a conciliatory gesture, for although the issue is still one of speculation it is clearly not without reasonable grounds...  Nah! - they've already gone too far by presenting their argument as unequivocal and undisputed fact - this is willful deception and deserves no mercy).

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That CAN'T be true! / Is there any known infection that could create zombies?

« on: 17/10/2010 22:39:15 »

They eventually decided not to use it as it was a little to sick, even for the us army.

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Just Chat! / Pick a number

« on: 17/10/2010 22:27:48 »

As for your signature Lee, that would be an ecumenical matter. []

Yes!

For those not in the know, the entire Father Ted series is currently available on 4OD.

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The Environment / Is there any risk living under power lines?

« on: 17/10/2010 17:17:18 »

You are both claiming an undisputed fact, but the proof of that fact requires proving a negative, which cannot be done.

The options are a) EMR from overhead powerlines does cause cancer, b) EMR from overhead powerlines doesn't cause cancer, or c) EMR from overhead powerlines may cause cancer.

Option a) is clearly untrue because people do live beneath overhead powerlines without getting cancer.  Option b) though, which is what you are both trying to claim is true, depends upon proving a negative.  Because a) is proven to be untrue, and because b) cannot be proven, I am therefore adhering to option c).

You can both believe whatever you want, of course, but until there's proof it must remain just a belief.

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Just Chat! / I suppose it was just a matter of time.

« on: 17/10/2010 16:58:07 »

The law 'system', after many centuries of practice and development, is supposed to consist of three separate and independent functions.  These are the establishment of laws, the apprehension of those believed to have broken those laws, and the trial of those who are believed to have broken those laws, along with their subsequent punishment if found guilty of breaking those laws.

The key feature of this scheme is the clear separation and demarcation between the three different roles in the system, this being to ensure that the system is impartial, treats everyone identically and cannot be used to unfairly persecute any particular group of people.

Thus, the police forces, who are responsible for the apprehension of those believed to have broken a law, should have no say in what laws are passed into acceptance and neither should they have any influence over the sentencing of those found to have broken a law, for if they did there would exist a state of affairs where the police, being the enforcers of the law, also get to chose who they persecute and how their targets are punished.  In such a state of affairs, the element of impartiality has been removed and the laws have become non-consensual.

On occasion, there will be times when the police force believe they have identified someone who has broken a law but are unable to conclusively prove it.  However, if the police believe that conclusive evidence is extant, but not directly available to them, they may apply for a 'warrant' to obtain it.  This warrant effectively allows the police to temporarily break the law themselves e.g. to enter private property without invitation (breaking and entering) to search for evidence, or to seize (steal) private property where that property is the evidence.  Because the warrant is allowing the police to break the law though, and because it would break impartiality, they cannot grant themselves that right; it must therefore be granted by one of the other two bodies in the law system who act in an overseeing role i.e. the elected representatives, who pass the laws, or the judiciary who, are responsible for establishing guilt and sentencing.  In practice, because there are relatively few elected representatives, warrants are generally issued by the judiciary.

So, by being able to attach a tracking device to someone's automobile without the need for a warrant, the police are breaking that person's right to privacy, which is currently not against the law, so there's not quite the issue of the police breaking the law themselves, but it most certainly breaks the principle of impartiality, for there is no judicial oversight to ensure that the police's suspicions and subsequent actions, along with the removal of the suspect's right of privacy are justified; the police are deciding who they persecute.

Of course, if the integrity of the police force was beyond doubt this wouldn't really be a problem but the trouble is that it has been shown many times that this is simply not the case.

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Physics, Astronomy & Cosmology / Is there any evidence for low mass blackholes

« on: 16/10/2010 19:19:10 »

I think there may have been some speculation that microscopic quantities of matter could be sufficiently collapsed by gamma or x-ray lasers.

Sorry, can't remember the references though.

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Physics, Astronomy & Cosmology / What is the mass of a BH when it reaches the end of its life?

« on: 16/10/2010 19:15:14 »

The temperature of BHs decreases with size, so a residual minimum size BH would also be the hottest a BH could get.  I also understand that the rate of Hawking Radiation increases with temperature, so I don't think that such a residual sized BH could be stable.

I believe that it's because of this factor that the folks at the LHC aren't too worried about creating microscopic BHs - they're believed to evaporate as soon as they're created (if they do indeed get created at all).

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General Science / Why can't I block out low frequency sounds as easily as high frequencies?

« on: 16/10/2010 19:08:12 »

Geezer: yes, the impedance of the driver will vary with frequency, but not so far as to take into completely different realms of voltage and current delivery.

elfabyanos: I think we should rule out the case of valve amps sounding better than solid-state amps when there's a significant degree of distortion - I entirely agree with what you say about our perception of odd and even ordered harmonic distortion - but ideally we want no distortion, at least in the reproduction of sound (as opposed to the creation of sound e.g. the 2nd order harmonic distortion in an electric/electronic instrument amplifier).

Other than that, the only things I'd like to add are that better quality components will have tighter tolerances and will be more linear, and that the power supplies will be likely to incorporate larger capacitors, capable of storing more energy and creating a greater reserve for when those large transients do occur.

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The Environment / Is there any risk living under power lines?

« on: 16/10/2010 18:41:41 »

No Geezer, I am not saying that low-frequency EMR produces cancer.

All I am saying is that EMR can cause cancer.

Because EMR is a continuous spectrum, where there is no clear and definitive point between one frequency and another, one cannot say definitively that a higher frequency will always cause it but a lower frequency will never cause it.

SteveFish: have you any evidence to suggest that EMR has a protective effect against cancer?  If there is such evidence then I'd happily give it a qualified acceptance.

Rather than discussing the issue, you both seem to be more intent on winning the argument, even though your argument depends, as I mentioned earlier, upon proving a negative.

Do you both actually acknowledge that your argument depends upon proving this negative?

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The Environment / Re: Global Warming - Are we too late to reverse the course?

« on: 16/10/2010 18:13:23 »

Sigh...

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That CAN'T be true! / Is there any known infection that could create zombies?

« on: 16/10/2010 18:06:53 »

The idea of a 'Rage' drug or poison sounds too much like an urban/contemporary myth/legend.

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Just Chat! / Pick a number

« on: 16/10/2010 17:54:39 »

Umm... 42 is not between 0 and 25.

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The Environment / Is there any risk living under power lines?

« on: 15/10/2010 19:52:49 »

That's a bad analogy Geez.

Whether someone gets cancer from exposure to EMR is intrinsically statistical, for amongst any group of subjects exposed there will be some that do and some that don't.  The fact that some do though, shows there is a clear link.  There's no such link to wearing cottons socks.

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General Science / Why can't I block out low frequency sounds as easily as high frequencies?

« on: 15/10/2010 19:46:27 »

which depends upon the current: a greater current flowing through the voice coil will have more authority and accelerate and decelerate the mass of the cone/dome against the air more quickly than a smaller current.

Sort of. It's a function of the ampere-turns in the voice coil. You can achieve the same force with a lot less current if you have a lot more turns. You could build a speaker driver that used a relatively a small current, but it would have to operate at a much higher voltage, so it really is power that's applied to the speaker to do work on the air.

Yes, having more turns in the voice coil would allow you to achieve the same force with less current and a higher voltage, but afaik that's not the case; neither active not passive crossover systems would work if the drivers had significantly different impedance unless you used equally different amplifiers, combining ones that delivered low voltage and high currents with ones that delivered high voltages and low currents, which isn't the case.  Like I said in an earlier response, the fact that similar amplifiers are used for the different drivers implies relatively little difference in the impedances, voltages and currents applying to those different drivers.

elfabyanos: thanks for your very well informed response.  I didn't know about the bespoke monitors with different custom amps for the different drivers.  However, I think I have to disagree with your assertion that low-power but high-current capability is really about the different between solid-state and valve amplifiers.  Excluding transformerless valve amplifiers, because they're pretty rare and overly expensive beasts, it's true that the output transformers in valve amplifiers result in a higher output impedance than typically found with solid-state amplifiers but the high current capability in relatively low-power solid-state audiophile amplifiers mostly comes from using a combination of over-specified power supplies and higher tolerance and quality components.  The higher-spec power supplies are able, on a transient basis, to deliver considerably more (clean) power than their continuous rating would suggest, but this then needs the higher tolerance and quality components in the signal path to cope with those transient bursts without degrading or failing.  Normally, in solid-state amplifiers, the peak power is a fixed ratio to the RMS power but in these audiophile amplifiers the peak power can be considerably higher.

A good part of the elevated prices one has to pay for these audiophile amplifiers is because of the higher spec components used in them.

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The Environment / Is there any risk living under power lines?

« on: 15/10/2010 18:44:55 »

Geezer and SteveFish: I said quite clearly that the probability...

...in this particular case is vanishingly small...

so while we all seem to believe that the risk is not worth acknowledging, you both seem to want to insist that the degree of risk is a definitive zero.  Sorry chaps, but you're trying to prove a negative here.

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Cells, Microbes & Viruses / Discuss: HIV Treatment in Rural Africa

« on: 15/10/2010 18:32:10 »

Mod edit - please format the subject as a question - this helps to keep the forum tidy and easy to navigate.

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Just Chat! / Are we all going to DIE?

« on: 15/10/2010 18:24:09 »

So you 'ussually [sic] don't belive [sic] in all of that prediction stuff' but the fact that someone is wearing a blue suite [sic] has changed your mind, even though the 'suit', being a set of matched garments made from the same cloth and consisting of at least a jacket and trousers, didn't exist until the early 17th century.

Aphophis, aka Apep, was an Egyptian deity.  You're probably thinking of Nostradamus, who died in the mid 16th century.

What I really don't understand though, is why some people seem to take the flimsiest and most ambiguous suggestions of impending disaster seriously.  Are people really that bored with mundane reality that they'll give up rationality for the most improbable speculation, especially when it's about something really bad happening?  It's as though people want these disasters to occur, with an extraordinary degree enthusiasm and relish.

Hmm... on second thought though, when one considers how many people play the lottery in the genuine expectation of winning, I suppose that they do.

Arthur Dent: "So this is it. We're going to die."

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Just Chat! / Pick a number

« on: 15/10/2010 17:52:01 »

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