1

Technology / Re: How can i Check internet Speed?

« on: 04/01/2020 17:29:39 »

Spammy speed test, Check your Internet speed ..........

No, you check our spam detection speed. Fast enough to avoid your spam attempt, but you can’t avoid our ban. Bye.

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Plant Sciences, Zoology & Evolution / Re: How many stomachs does a hippo have?

« on: 03/01/2020 17:56:04 »

The hippo was a bit grumpy, but the guide managed to scare it off before we discovered how many stomachs it had...

If you had virtually hung around you would have discovered that the hippoptumus (hippo to friends) is a pseudo-ruminant having 3 stomachs rather than the 4 of the true ruminant. Apparently they don't ruminate (chew the cud), it all takes place, after the initial crushing, in the stomachs.

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Physics, Astronomy & Cosmology / Re: Can Two Bits Of Light Bounce Off each Other ?

« on: 16/12/2019 18:18:35 »

This is not like throwing 2 sheep at each other.
The light will superpose or interfere, but you need very special circumstances to see it, so it usually appears as though the 2 beams have passed through each other.
However - there is often an however - two photons heading towards each other can collide indirectly. Two photons can spontaneously degenerate into a particle with mass and its antiparticle in a process known as pair production. So, if two photons head towards each other and they both turn into electron/anti-electron pairs at about the same time, then these particles can interact. The anti-electron from one photon will collide with an electron from the other photon, and turn back to light. The same thing happens to the other anti-electron and electron. The overall effect is that you get two photons going in and you get two photons coming out, so it looks like the photons bounced off each other. But that’s not what really happened and again, it needs special circumstances.

Where do norty light rays go ?
Prism !!

guffaw chortle !!

Ah yes, but they’ll have time to reflect on what they did wrong 
guffaw chortle !!

4

Physiology & Medicine / Re: Can Liquorice Really cause High Blood Pressure ?

« on: 16/12/2019 14:48:43 »

unless i've missed them, i have never seen a warning on a pack of liquorice. not good.

The liquorice labelling act (2019) has been delayed by Brexit taking all parliamentary discussion time for the past n years. Perhaps when the log jam has cleared ......
Don’t hold ewer breath however, as the focus is shifting north.
Like all things parliamentary, it’s a bit woolly - just as you like it.

PS now that free movement will cease there will be a shortage of imported lamb, so more pressure to use our in-country resources. Sorry to bring bad news.

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Physiology & Medicine / Re: Can Liquorice Really cause High Blood Pressure ?

« on: 16/12/2019 09:08:30 »

Strange as it seems liquorice can cause dangerously high blood pressure and dangerously low potassium levels (hypokalemia).
It contains glycyrrhizinic acid, which sets off the mechanism which results in high blood pressure.

6

Physics, Astronomy & Cosmology / Re: How can quantum entanglement be proven?

« on: 11/12/2019 22:57:59 »

but have they measured the deviations?

Yes, should be in most textbooks. You get an eye diagram, one line above one below axis depending on whether up or down spin.

And you keep referring to the standard classical approach for this paper? There is no stl (slower than light) information involved in it as far as I've seen?

Classical means light speed or slower, not just stl.
Classical is mentioned right up front.
From paper:
“Abstract
Protocols of quantum energy teleportation (QET), while retaining causality and local energy conservation, enable the transportation of energy from a subsystem of a many-body quantum system to a distant subsystem by local operations and classical communication through ground-state entanglement. ........”

Look at the diagram I sent, it shows the classical data channel which is part of all teleportation experiments.

Seems we have to agree on disagreeing here Collin, as far as I get you you define it as only (theoretically) extracting the energy of the 'second particle'? Or do you read it as it extract more that that, but not the injected energy?

No, the paper says extract the same amount of energy at B as was input at A. I have highlighted in the quote you gave:

" The relationship between energy and information has been investigated extensively in the context of computation energy cost including a modern analysis of Maxwell’s demon [1]-[2]. In this Letter, we show a new energy-information relation from a different point of view. Recently, it has been reported that energy can be transported by local operations and classical communication while retaining local energy conservation and without breaking causality [3]-[5]. Such protocols are called quantum energy teleportation (QET) and are based on ground-state entanglement of many-body quantum systems including spin chains [3], cold trapped ions [4] and quantum fields [5].

By performing a local measurement on a subsystem A of a many-body sys-tem in the ground state, information about the quantum fluctuation of A can be extracted. Because the post-measurement state is not the ground state in general, some amount of energy is infused into A as QET energy input during this measurement, and the ground-state entanglement gets partially broken. Next, the measurement result is announced to another subsystem B of the many-body system at a speed much faster than the diffusion velocity of the energy infused by the measurement. Soon after the information arrives at B, energy can be extracted from B as QET energy output by performing a local operation on B dependent on the announced measurement data. The root of the protocols is a correlation between the measurement information of A and the quantum fluctuation of B via the ground-state entanglement. Due to the correlation, we are able to estimate the quantum fluctuation of B based on the announced information from A and devise a strategy to control the fluctuation of B. By the above-mentioned selected local operation on B, the fluctuation of B can be more suppressed than that of the ground state, yielding negative energy density around B in the many-body system.

The concept of negative energy density has been investigated in quantum field theory for a long time [6]. Quantum interference among total energy eigenstates can produce various states containing regions of negative energy density, although the total energy remains nonnegative. The regions of negative energy density can appear in general many-body quantum systems by fixing the origin of the energy density such that the expectational value vanishes for the ground state. In spite of the emergence of negative energy density, the total energy also remains nonnegative for the general cases. In the QET protocols, during the generation of negative energy density at B, surplus positive energy is transferred from B to external systems and can be harnessed as the QET output energy. Here it should be emphasized that this output energy existed not at A but at B even before the start of the protocol and was hidden inside the zero-point fluctuation of B. Of course, this zero-point energy is not available by usual local operations for B.

However, by using a local operation dependent on A’s information, it becomes possible to dig out B’s zero-point energy by pair creation of the positive output energy from B and the negative energy of B. Hence, we do not need to hire any physical carrier of energy from A to B like electric currents and photons, at least, during short-time QET processes. Needless to say, after the completion of QET process, the positive energy of A compensates for the negative energy of B during late-time free evolution of the many-body system. The amount of output energy from B is upper bounded by the amount of input energy to A. "

Remember, all you are doing is measuring the state of A, sending info about that to B so that you can operate on B and put it into the same state as A. See above where it says “by using a local operation dependent on A’s information, it becomes possible to dig out B’s zero-point energy”.

But it also seem to allow for a communication FTL?

I don’t see that it says that anywhere. Can you point it out?

Although, thinking of it, all entanglements where you 'know' when to measure on the 'second particle' involves a slower than light arrangement, where you set a time for A and a time for B.  So there is always a 'classical conection' between the two, even if not measured on yet.
=

that is to say, to 'construct' a entanglement is to use classical information. Or better expressed, measuring on them getting a outcome, is a result of a prearranged construction and order of causality. And that one is still classical even if the opposite 'spins' found are instantaneous.

That’s not what is being done here.

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General Science / Re: When do YOU die in a many worlds interpretation?

« on: 10/12/2019 15:56:42 »

.... if these waves/particle were in a superposition wouldn't the effect on the surrounding space be greater?

If the particle in superposition has an effect on the surrounding space this would in effect be a measurement and hence we could detect the state and the particle which would no longer be in superposition but in a defined state.
Note: a particle in superposition is not particles (plural) but particle (singular).

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Physics, Astronomy & Cosmology / Re: How can quantum entanglement be proven?

« on: 10/11/2019 08:35:59 »

If you knew the state of one particle,  then observing the other particle  you should know how the first particle is behaving. 

As explained by @Kryptid the 2 particles (if we simplify things and take an example of electrons) are in opposite states (to be strictly correct they are in a superposition of correlated but opposite states) but you don’t know which state either one is in until you check it out.

Surely this could convey information.

When you check out either one you know the state of the other, in other words acquiring information on one gives you information on the other.

As @jeffreyH says, there are additional complexities, but at a basic level this is how it works.

9

Physics, Astronomy & Cosmology / Re: Do things stop decaying in space?

« on: 10/11/2019 00:20:54 »

talking about Voyageur 2, that it would go on travelling in space for billions of years. This suggests that it will never break down/'decay,change. is this true of anything that gets into space?

In a vacuum there is no friction or resistance to motion so even if Voyager breaks down or changes what is left will keep on moving at the same speed - unless it hits something.

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Plant Sciences, Zoology & Evolution / Re: How do dolphins and whales breathe when asleep?

« on: 08/11/2019 14:35:14 »

A bottlenose dolphin shuts down only half of its brain, along with the opposite eye, while the other half of the brain stays awake at a low level of alertness. The attentive side watches for predators, obstacles etc, it also signals when to rise to the surface for a breath. Every two hours, it will reverse this process, resting the active side of the brain and awaking the rested half. This pattern is often called cat-napping.
Dolphins also enter a deeper form of sleep, mostly at night, called logging because the dolphin resembles a log floating at the surface.

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Physics, Astronomy & Cosmology / Re: What happens when both slits are observed by in the double slit experiment?

« on: 08/11/2019 12:28:03 »

I think it's fair to say that I could not get into any meaningful discussion with you guys because of our differing levels of scientific/mathematical understanding on the whole subject.

I hope we can still have a meaningful discussion, and I’ll try not to be too technical. The maths is only a description of what happens, but sometimes it’s hard to put into words which is why the popsci press opt out and give oversimplified explanations.

seemingly a particle before the double slit and a wave after the double slit ... and reverting back to a particle when 'observed' after the double slit.

The wave or particle is only a description of how the light behaves, not really a description of what it is.
Ok, to keep it simple and stick with light. When light is emitted by an atom it is as a very short burst of electromagnetic oscillation - a short wave. So that burst, which we call a photon travels as a wave, but the way we detect it requires it to interact with another atom. That atom could be in a photographic film or in a camera ccd, but that interaction shows up as a dot, just as if a particle had hit the detector. In other words, when the wave hits the detector it can be modelled as a particle. This is why you often hear physicists say the photon travels as a wave but is detected as a particle.
It is fair to say that most modern physicists consider the wave/particle duality thing a bit ‘old ways thinking’, they are more likely to ask how you are detecting or measuring the result of your experiment.

The point is that the photons travelling through the slits should produce an impact pattern similar to the double slits.

‘Should’, but only if they are travelling and behaving as particles. Electrons are interesting because we tend to think of them as particles - little hard bullets - but when they are moving they clearly behave like waves, if fact when they were first discovered they were called cathode rays (which is where we get the name cathode ray tube).
One thing I should mention here is that the prime objective of physics is not to provide an explanation of why something happens, the objective is to observe, model and predict behaviour; that’s what Newton did, he didn’t explain gravitation he just described what it did - with very useful accuracy. His model was of a force acting at a distance, today we model it as a field through Einstein’s field equations and that’s a little more accurate.
Sometimes we can see clearly how a thing works, eg we start a car and the wheels push against the ground providing a force that moves the car forward. Some other thing are less easy to predict eg we flip a coin, we can’t predict exactly which way up it will land, but we do know that in a large number of flips we will get approximately 50:50 and we can do a lot of predicting with the uncertainty of which way it will land. This same uncertainty works at the quantum level and allows us to use probability to make some very accurate predictions - we might not know the exact position of an electron in an atom, but we can make very accurate predictions about where it will spend the majority of its time.
Probability is worth learning about because it really helps us understand a lot about the world around us. So, I’m going to go a bit technical and hope you will follow us by learning more about probability.
When we fire bullets (particles) at a slit they will, as you said, go through one slit or the other and form the 2 slit shadow we expect. This is because in probability we say the events of a bullet passing through one slit or the other are mutually exclusive (it can’t do both) and more importantly neither action can influence or have any effect on  the other (we say they are uncorrelated). In probability mutually exclusive, uncorrelated evens follow the sum rule, their probabilities add which is what we see with bullets, but with quantum objects which are coherent, it is the square of the sum which gives us the probability of what we see on the screen. There is growing evidence that this is the way the world really works, but at our big world level we lose the coherence between quantum objects and we start to see the probabilities we are used to. However, when we come to modelling the slit experiment we can look at it and say that the electrons going through both slits is one way of modelling it because it works. So when physicists say it goes through both slits and interferes with itself, they are really using a shorthand for ‘that’s the way we can model it’. At the moment we don’t have enough information to know exactly how this works, but we can predict what happens to a very high degree of accuracy.

@jeffreyH  has put up a video of polarisation, this raises another problem which occurs when we view the quantum world. We view polarisation as horizontal/vertical, right/left and electron spin as up/down, just as we would say a coin is heads/tails. But it’s not that simple and the polarisation and spin are best represented as complex numbers (which can also be represented as vectors).

PS Looking back I notice @alancalverd has given a very similar explanation to mine, please read it carefully it’s important. I hope mine has some extra detail you find useful. Remember, 62 is not too old to learn about probability, vectors etc, keeps the grey cells on their toes.

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Physics, Astronomy & Cosmology / Re: What happens when both slits are observed by in the double slit experiment?

« on: 05/11/2019 17:07:47 »

(although from observing the experiment without the detector I would class as observation anyway?)

In quantum physics ‘observe’ has a very specific meaning. It doesn’t mean that someone stood there looking at the experiment, it means that the presence of a particle or wave was detected.

The question I was trying to ask was ... what if there were 2 detectors observing both slits as opposed to just the top one?

It’s important to recognise that the 2 beams are not just any old beams. In order to get interference between 2 electron beams they have to be coherent; that means all the electrons have the same energy (frequency) and the phase relationship is stable - this latter being arranged by passing the beam through a narrow slit called a collimator. These are the same requirements for a light beam to be considered coherent. If anything disturbs the energy or phase then you will not get an interference pattern.
If you place a detector above a slit to measure the passage of the electron it must interact with the electron in some way and if this changes the energy or phase the beam will no longer be coherent - this is known as decoherence. This is why I said that you need to understand the detail of an experiment to know what is happening.
Each time this experiment is performed in different ways we learn more about the quantum world, unfortunately the popsci press rarely give enough detail, choosing to present the results in the most top level and dramatic terms possible.

I think @Halc has answered your main question, you won’t get a double slit interference pattern if you disturb the electron in any meaningful way at either or both slits.

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Physics, Astronomy & Cosmology / Re: What happens when both slits are observed by in the double slit experiment?

« on: 05/11/2019 09:08:44 »

I'll do a bit more reading and watching.

What @Halc is pointing out is that you have to know in detail how an experiment has been done in order to understand the result. In particular, how did they detect the photons without destroying them of affecting them in some way.
Do come back with more questions on this, because I think you will have a lot.

14

Chemistry / Re: Why does egg white turn from translucent to white when whipped?

« on: 01/11/2019 22:19:58 »

Denaturing of the protein causing it to form an emulsion rather than a clear solution

Certainly the protein chains uncurl and change the consistency of the egg white allowing it to form bubbles.
I’d agree with the light reflecting idea due to many small reflecting surfaces in the mixture.

15

Just Chat! / Re: It is a good day to eat meat

« on: 26/10/2019 08:50:16 »

This past weekend I decided to cook a 7 bone chuck roast .......

So, trying to sell cigs eh, but we smoked you out.
Now we are going to turn you to ash and stub you out.

16

General Science / Re: If we need to colonize Mars in a hurry, how do we choose the best people?

« on: 24/10/2019 08:56:44 »

...... they will find that they are quite unattractive to men.

I’m not sure that would be a problem.
You could always give them a photo of Alan 

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Physics, Astronomy & Cosmology / Re: Is light an independent entity, or is it an effect of a larger mechanism ?

« on: 14/10/2019 12:51:34 »

The analogy breaks down (as do all classical analogies of quantum phenomena, eventually)

The problem with all classical analogies of quantum, as you say and also the difficulty of trying to explain to someone with the level of experience as @HelpMe929
A similar problem is with comparing classical and quantum probabilities. We tend to think of spin, for example, as up or down (like a coin, heads or tails) but, as you know, the quantum description is much more complex.

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Physics, Astronomy & Cosmology / Re: Is light an independent entity, or is it an effect of a larger mechanism ?

« on: 14/10/2019 10:11:54 »

Concerning a particular type of particle which, when its 'state' was changed then a matching particle's state also changed - instantaneously, no matter how widely seperated in distance (thus appearing to break the lightspeed limit).

You are hearing about entangled particles. Difficult to describe in detail, but it has to do with correlation and quantum statistics and also what we know about the particles.
An analogy: lets say a friend puts a rh glove in one envelope and a lh glove in another but doesn’t tell you which is which. We could say the contents of those envelopes are entangled and there is a correlation between the ‘state’ of the gloves in each envelope.
So, you now send one envelope to another person on other side of the world and keep one. If you open your envelope (measure the state of your glove), you instantly know the state of the other glove, but nothing has changed other than your knowledge. We can do the same with particles eg electrons or photons and when we measure the state of one we can be sure of the state of the other.
However, quantum statistics are more complicated than everyday statistics so this is a fascinating area of misunderstanding, and you will need some maths to understand what is happening.

19

Physics, Astronomy & Cosmology / Re: Is light an independent entity, or is it an effect of a larger mechanism ?

« on: 13/10/2019 09:09:29 »

So the question is this, is light an independent entity or is it somehow an observed effect of a larger mechanism.

It all depends what level you are talking about. Clearly, light is just a part of the overall electromagnetic spectrum, which is an effect of oscillating electric/magnetic fields. So you would say that light is an observed effect of the laws of electromagnetism. Remember, Einstein’s first paper on relativity dealt with a specific problem in electrodynamics (moving electromagnetic fields) that had been puzzling scientists; it was in that paper where he suggested light does not behave as if propagated in a medium so it’s measured speed is not affected by the emitter or observer. This speed also comes from Maxwell’s equations which are based on the findings of Amper, Faraday, Coulomb and Gauss - all leaders in electromagnetic theory.

20

The Environment / Re: What's the difference between a typhoon and a hurricane?

« on: 12/10/2019 23:12:53 »

Surely the answer is that we've had a hurricane - but not a typhoon - in snooker...?

If his surname had been Timmings you could have had Typhoon Timmings.