studiot

Great stuff MigL, straight to the point. At what stage can we call 'imaging', seeing ? There are other processes for creating an image, including ones that cannot be observed by visible light, such as electron microscopy and seismology. So we need separate terms for imaging and seeing. As to visible and invisible. I am happy to pair these with seeing and define invisible as that which can't bee seen and visible as that which can. But does seeing refer to creating the image or the abstracted model? A camera can create an image. And we use general English to talk of the camera 'seeing' and (in)visible to the camera or the naked eye.

I have provided my hard physics thoughts in the original thread for comment.

I agree we need a working definition of seeing and in order to have that we need a working model of the process, since seeing is a process, not an object. So I offer up such a model for discussion and improvement. Firstly let me observe what seeing is not, since it has been suggested that seeing is synonymous with detection. I suggest that detection is a much more general process with a variety of outcomes. Many (most) parts of the body can respond to light in some fashion. Thus they can be said to detect light. For instance the action of light on the body produces chemical change resulting in vitamin D production. Other action produces the melanin tan. Yet other action synchronises the bioclock or tells us to wake or sleep. For any of these actions and more, a particular form of light is required so the activity can be said to detect or distinguish that form of light from other forms. However each interaction is separate from and unconnected to any other interaction. So one particular UV photon that kicks off a secosteroid production is independent of another such event. But in the process of seeing our eyes not only form a real (in the optical sense) image of all the light enetering but also generate information signals coding the relationship (if there is one) between all the photons. Note a modern camera sensor mimics this in a crude way. So is the process of formation of this image 'seeing' ? Or is there yet more to it? Well the answer is 'there is more to it', since each of these images is a two dimensional representation of the same thing from a slightly different viewpoint, so can be processed to yield a three dimensional model of what is in front of the viewer. In animals, including humans, this processing is done by the brain. But what is this model of? Is it of an object, as has been suggested? Well no because the eye will still produce the image and the brain the model if there is no object there. For instance in a whiteout in snow or fog we will still receive light and 'see' something. Further, otical illusions of many sorts abound, where the system is tricked into producing a false model. Or artificial stimulation of part of the chain can also produce false models or block real ones. So is seeing the successful conclusion of the chain of sub processes which make up an overall process? I look forward to comments.

Yes I think every viewer (pun intended) of this thread agrees that. But many viewers have told you they use a different definition of 'see' from you. In my experience, theirs is overwhelmingly the most common one. That does not mean to say you are not correct about what goes on in the mind in the formation of a mental model of the image. But that is irrelevant, and until you are prepared to discuss that, no progress can be made.

One very important way to get others to take your thoughts seriously is to offer them the same courtesy. Endless repetition of contentious statements does not folllow that well advised path. Such as here. You do not need to simplify. You need to flesh out your argumentt with more deductive detail. And in this next example you simply need to read properly what the other poster has written. No we don't see sounds. But then dimreepr didn't suggest that we do. In fact I find his example completely logical as, I suspect, do many others so +1 to him. In fact IMHO your posts contain a mixture of generally validated statements and some outrageous ones. It is the deductive connections to the outrageous ones we are all querying.

Unfortunately explaining is the one thing you refused point blank to do, despite being asked to do so. Would you like a list of where you mocked instead?

David Eagleman (whoever he is) is not a respondent in this thread. You have already been warned about forum rules. You are a respondent, and I have already noted that the onus of supporting claims you makes lies squarely on your shoulders. You are simply making claims and alleging that they are true. You are not providing any form of scientific verification for them or making any attempt to show that they are self consistent. I have already shown several instances where they are not.

Another flatout contradiction. When it suits your case you speak as though your interpretation is fact. In fact you state it as a fact. (pun intended) This gives the 'head' you are talking about more credence than the cinema and everything else in the world around us. There is an old saying "What is sauce for the goose is sauce for the gander" Finally please lay off the personally directed statements such as "You're not getting it."

Like the fairies at the bottom of the garden? You have just trashed the entire scientific method. And that's the third time now you have been personally insulting about my reasoning powers.

Yes indeed we can perceive a shape through contrast and that is how we can 'see' a black dog on a white screen. But what if the dog was a real black dog running across the podium, in front of the screen? We would still see a black dog running across the screen. Anyway let us move on. Let us examine your claim that the image colour we see is independent of light and only a function of the processes within our heads. Let us do that in a proper scientific manner in accorance with the rules of evidence. So let us consider a blank cinema screen and a projectionist with light projector equipped with a range of coloured filters. Let us watch as the projectionisd projects a circle of light onto the screen. We observe a red disk, then a green one, then a blue one and so on. Your claim fails at this point because the only change that has been made is by the projectionist. We see a red disk and can identify this later with the red filter being in place and can do this repeatedly. We never see a blue disk with that red filter in place, and similarly with the blue and green filters. So there must be something about the light from the red filter that is different from the light from the blue filter, that cuases our internal imaging system to note a red or blue disk. By definition this light is defined as red light and the blue filter light as blue light and so on. That is scientific deduction in action as opposed to someone wildly asserting vague nonsense.

You claimed that the only way for us to see an image, regardless of where it resides or the mechanism of generating that image, is using light. Yet you then tell me that I can see a black dog, because there is no light. This is a flat out contradiction and no amount of hand waving and burying it in obscure language will alter that. You told me that a cinema screen emits light. That was flat out wrong.

No, so enlighten me. (pun intended) In particular, what does that have to do with a Physics question in a forum entitled Modern and Theoretical Physics?

Why subjectively? Science is objective. This is a Science website. Please discuss Science, not your personal misinterpretation of both the general English language and Scientific English. I have clearly demonstrated where you declared black to be a colour. I have also clearly demonstrated where you have contradicted this. If I can't comprehend your answers it is because they are lacking rigour and self contradictory. You are the one making the claims, so it falls to you to supply the evidence, deductive or otherwise.

So this earlier post was incorrect then? If colour is created why does it 'not exist'? You appear to have contradicted yourself, since you have already agreed that black is a colour.

I didn't ask where the colour exists. I asked what colour is the screen? Please don't dodge the question.

So what colour is the screen at the cinema? And please note that a cinema screen does not emit light. It reflects light.

Are you saying you have never been to the cinema?

Hi Koti, this is an engineering problem. Are you familiar with the electrical/electronic engineering term 'Thermal Resistance' ? The answer is not as simple as a Physicist might offer since there are several bottlenecks or restrictions in the heat path. This is rather like a series of valves or taps in the flowline of a fluid. This is why manufacturers publish values of thermal resistance, which are added up. For your heat source the manufacturer will publish the controlling figure for the controlling bottleneck . This is the junction to case resistance of the LED source. You then have the case to mounting plate resistance Then the mounting plate to heatsink resistance Then the heatsink to ambient resistance which will depend upon the colour and orientation of the heatsink plate. Good values for all of these are available, though I doubt that there would be any for a lead heatsink. Formerly these were empirically measured, but modern finite element techniques provide very close estimates. Sorry I no longer have access to such software. Here are some references, let me know if you want more help. https://www.sparkfun.com/tutorials/314 https://www.electronics-cooling.com/1995/06/how-to-select-a-heat-sink/ https://www.electronics-cooling.com/1995/06/how-to-select-a-heat-sink/

The time angle makes a good point. +1

In case you missed my post whilst you were concocting all that, I look forward to your replies to my post, sandwiched between two of yours.

It is actually you who wishes to make this a reductionist argument. Nature is far more complex than you make out. OK, now let me ask you The dog is black and I am watching it on cinema screen. What light (from the dog) are my eyes actually interacting with? IOW How do you project black onto a screen? Further examples of complexity. In my time I have used side scan sonar and electron microscopy. Neither use photons, yet both allow me to view images of objects.

Well spotted +1

I am going to assume you have posted your paper for comment and critique and that English is not your first language. So at least some of my comments may bue due to a language problem. **You need to explain exactly what you mean by ‘constant’ speed of light because just stating it is constant or observed to be constant could mean several different things. **I beg to differ. Even in Newtonian theory the frequency of the spring will vary with position in the gravitational field. This simple (http://hyperphysics.phy-astr.gsu.edu/hbase/shm2.html) form of solution takes g as independent of x and therefore constant (note yet another use of the word constant). But strictly g is not the same on the floor and on the table. **This is too wide a definition of inertial. Newton’s laws still apply to in non inertial frames, just differently. **Einstein introduced the third frame to define an unknown function (and show that it is equal to unity) he introduced for the sake of mathematical completeness. You have omitted this step, so the third frame is unnecessary. **not speed, but relative speed. Speed by itself requires reference to a particular frame. The point is that relative speed is the same in both frames. **The rest of this paragraph has the seed of a correct point but is garbled and needs rewording. In particular speed is not acceleration. **Really? So driving my car at 100mph is more fuel efficient than driving it at 50 mph?

The purpose of this thread is to discuss the current tectonic activity around the Pacific Rim. Mods please move to Earth Science if you feel it fits better there. The Alaska quake is the big news, but there is other activity to consider - volcanic in japan and Indonesia. Here is my contribution to kick off. If anyone could embed the video I would be grateful http://www.bbc.co.uk/news/av/world-asia-42785939/the-philippines-most-active-volcano-mount-mayon-erupts