robinpike

If you are going to use Javascript, it can be used for animation by drawing shapes on the html 'canvas' element, which are then redrawn as a loop using requestAnimationFrame(). This works well if you are going to plot points / basic shapes using an equation. If you want a 3D animation but for simplicity are going to use canvas in 2D, a trick is to calculate the shapes as 3D into an x y z array, include an adjustment for the size of the shapes with regards to perspective, sort the array on what is furthest away from the point of view, and then draw the shapes as 2D onto the canvas in that order. This produces a 3D animation. Otherwise WebGL can be used for 3D plotting onto the canvas but I have not used that myself. Notes from w3school https://www.w3schools.com/html/html5_canvas.asp The HTML <canvas> element is used to draw graphics, on the fly, via JavaScript. The <canvas> element is only a container for graphics. You must use JavaScript to actually draw the graphics. Canvas has several methods for drawing paths, boxes, circles, text, and adding images.

Our ability to be 'more conscious' than say a zebra, would seem to be a result of our ability to communicate using a complex language, rather than because we have a brain that is constructed 'with a greater consciousness'. Imagine a group of modern day people living on the African plains that happen to have never learnt a language. The communication and behaviour between those people would be basic - possibly even similar to the way a group of zebras behave. And yet for this to be so, the construction of their brains need not be changed from that of a modern day person.

Perhaps the following example shows how science and philosophy can be different. When we consider quantum mechanics, science is able to model reality with QM maths, matching what is observed with what is calculated by the model. Note that science doesn't have to answer the question: How does the mechanism of quantum mechanics work? Or what is QM? If we do ask, 'How does quantum mechanics work?', this perhaps leads to philosophical reasoning. For example, on trying to explain QM, we note that it has aspects that are very difficult to explain in physical terms, such as quantum spin, quantum entanglement, etc. So philosophically, we could use the inexplicable physical aspect of QM to arrive at the conclusion that we exist in a simulation! ...since a simulation could have QM in it without the necessity to have a physical mechanism for that QM (which of course reality must do).

And to make it clear on the above point, it is not about the likelihood (or belief) of what we are, but what can be proved absolutely. Just to be clear, if you mean day by day the 'person simulator' experiencing the same stimuli, bear in mind that the 'person simulator' would be a learning program, in the same way that when we learn, we may change our response to the same stimuli.

But in the example given, how would the computer know that it is not a living thing?

Take this example. All the inputs that feed into a computer inside a driver-less car are recorded and these are then input into another computer sitting in a lab somewhere, running the same driver-less car software. Can that computer tell that it is not in a driver-less car, controlling it down the road? Suppose all the inputs that a person receives during their life were to be recorded and then played back to a computer running a 'person simulator'. Would that 'person simulator' think that they are alive and real? How would the 'person simulator' know that they are a simulator and not a living creature?

When light is outside of a black hole's event horizon and is moving away from the event horizon - I understand that the light is red shifted, but can someone just confirm that the light still moves at the speed of light at all times? I was reading another post on black holes, and it talked about light 'hovering' near the event horizon and wondered what that meant.

Thanks Delta1212. The difficulty with the ant on the expanding balloon analogy and bearing in mind we are in a 3D world, is that it requires our 3D world to expand into the 4th dimension. That introduces the issue of what is dragging us in that direction? In the analogy, the rubber of the balloon is pushing the ant into the third direction. What are we 'standing on' that pushes us into the 4th dimension?

Thanks Strange, but still don't follow the explanation for the expansion of the universe. Dark energy seems to be the most common answer when searching on Google, but here are three options as far as I understand their merit / issues... 1) If the expanding universe were to be due to space expanding literally, then that would suggest that things are pegged to their position in space while space in between increases, causing them to drift apart. But since we are able to move through space unimpeded and are not pegged to a position, that explanation doesn't work. 2) If the expanding universe were to be due to the things in the universe shrinking in size - then the distances between them would appear to be increasing - so that would be an alternative way to get the above to occur. But if that were the case, then distance objects would not occur any red shift - and that contradicts what is observed. 3) If the expanding universe were to be due to dark energy pushing things apart, then that seems to be a better fit to what is observed. But a couple of questions. 3a) If dark energy is the explanation, wouldn't distant galaxies be constrained to move apart within the speed of light? So although at this moment, light from the most distant galaxies hasn't had time to reach us, eventually all galaxies would come into view? 3b) If dark energy is the explanation, how is it able to push against things, and yet when those things move due to local forces, those things do not experience a drag through the dark energy?

Thanks, that explains how light may not be able to reach every part of the universe. Is it the case that we are happy with how the accelerating distance between galaxies occurs? Or are there issues? For example, if the increase in distance between galaxies is due to 'dark energy' pushing the galaxies apart, wouldn't objects generally moving through this dark energy feel a drag - and slow down? Or is 'dark energy' like photons, in that regardless of your own speed and direction, 'dark energy' moves at the same constant speed to you, regardless of the speed and direction of your own reference frame. But even then, wouldn't a Doppler shift in the amount of energy of the 'dark energy' still occur for some speeds / directions? Or perhaps is it that space has 'substance' - and it is space itself that is increasing between the galaxies - and dragging the galaxies with itself? But then wouldn't the same problem occur for objects generally moving through space, in that they would experience a 'drag' from the space, and slow down? Just wondering if these are valid issues or not?

A small point, but to be pedantic... The absence of a 'feel' of acceleration isn't an absolute test that acceleration isn't occurring. For example, acceleration by gravity affects all the atoms in your body - free falling in space in a gravity field doesn't produce a feeling of acceleration. If I am understanding this correctly... IF space were to be expanding at a constant rate, then the amount of separation between two galaxies is irrelevant, for the rate of separation between the two galaxies would remain the same. [in the escalator example above, when you run, either you can always reach the other person, or you can never reach the other person. The starting distance between you and the other person is irrelevant.] So, even when the distance between the two galaxies is very large, with a constant rate of separation, and assuming a rate of separation less than the speed of light, then light can always reach any other object. The only impact of two galaxies being a great distance apart, is that the light will take longer to reach the other galaxy. Please can some one step through the explanation of how expansion (whether at a constant rate or increasing over time) is able to prevent light from reaching a distant galaxy? I do not understand how that is possible.

I think this refers to the suggestion that if objects with mass were to 'prefer' to be in a state with the least rate of time, then this would cause objects with mass to move towards other objects with mass. Since mass bends space-time, and time runs slower the nearer the objects are to each other, thus the attraction attributed as gravity could be just the objects moving so as to be in a state of lesser time. I don't know if this idea has any merit.

I read this as meaning that logically it is impossible for the universe to exist - therefore it is amazing (shocking) that it does exist. The steps in logic being... i) If starting from a state of true nothingness, then it is not possible for the universe to come into existence. ii) Therefore the alternative must be true - that the universe started from a state of something. iii) But that then leads to the question of where did the "something" itself come from? and we are back to i) Hence a logical paradox that must be flawed - since the universe does exist.

Evolution of us is an example that intelligence is not needed to create intelligence. There is no intelligence driving what changes should / do occur to a life form.

Since entanglement versus classical pairing predicts different results when the filters are at the same angle, does anyone have a reference to those experimental results? Those results will be easy to analyse. Thanks, seeing the results for such a straight forward experiment would be really helpful - I've only been able to find results for when the polarizing filters are at angles. At the moment, I have a mental block on quantum entanglement being real, but on seeing the results, would accept it in preference to 'spooky action at a distance'. Thanks, this is starting to become clearer as to what local hidden variables means and why something was needed to discount them, i.e. Bell's inequalities.

I've only seen results that support entanglement... but those experiments do not have the polarizing filters at the same angle. Those experiments typically have the polarizing filters at a difference of 120 degrees and Bell's inequalities are used to assess if the results agree with entanglement or classical pairing. The analysis of those experimental results are complex to follow. Since entanglement versus classical pairing predicts different results when the filters are at the same angle, does anyone have a reference to those experimental results? Those results will be easy to analyse. Indeed, why is it even necessary to devise a complicated experiment involving Bell's inequalities?

Thanks Swansont. Is it possible to perform the experiment such that the photon pairs can be detected as individual hits on their respective photon detectors and therefore the hits correlated as being from the same photon pair? If so, then entanglement will produce pairs of hits being detected at the same time (for a perfect experiment, entanglement will produce detection at the same time or both detectors nothing). Whereas classical pairing will, as you mention, produce 25% of the time you get both photons, 25% of the time you get no photons, and half the time you get one photon at one detector but not the other. Assuming the above to be correct, has this type of experiment be performed? If so, did it demonstrate entanglement or classical pairing?

I find it difficult to follow the analysis on experiments that investigate quantum entanglement, there seems to be something fundamental about quantum entanglement that I am missing. Perhaps if I step through a simple example, it will show up what it is that I am misunderstanding. Say a source of entangled photon pairs are used in an experiment, such that the photons pass through two vertically orientated polarizing filters, positioned either side of the photon source, with one filter slightly further away from the source than the other. For the sake of simplicity, it is assumed that the polarizing filters are perfect - that any photons that make it through are polarized to the orientation of the polarizing filter. For the photon of an entangled pair that reaches its filter first, its wave function collapses and its orientation is at some, random angle to the filter. At that same moment, the other photon collapses its wave function too - and its orientation is at 180 degrees to the other photon's orientation. The probability of a photon passing through a filter is dependent on its angle of orientation, and with an equal probability of any angle occurring, 50% of the photons will make it through the filters, and 50% of photons will fail to make it through the filters. Except for the special cases when the photons are at 0 degrees to the filters, or at 90 degrees to the filters - where either both photons pass through the filters, or both photons fail to make it through the filters, there is a probability of whether a photon is absorbed or not, based on the angle of the photon's orientation to the filter. In these cases, there is no guarantee that if one photon of the pair makes it through its filter, then the other photon will too, and vice versa. So how is this different to the classical view, where the photon pairs are emitted with an orientation that is at some random angle to the filters, with the orientation of the two photons being at 180 degrees to each other? Or is it, that for this particular set up, there is no difference between the two explanations?

Tim, even if some processes have random outputs, I don't think that will give us free will as we have no control over that output? Eise, evolution means that our brains are constructed so as to produce rational thoughts but nonetheless we are constructed from atoms. So yes, atoms can produce rational reasoning but I don't see how atoms can produce free will?

Something that is lawful, or something that is accepted by a majority, does not make that something ethical. Ethical and lawful are separate things - although hopefully the two overlap. As Tampitump says, ethical / moral has a predefined intention - it is not relative. Ethics deals with such concepts as: upholding rights that are self-evident, protecting those that need protecting, ensuring fairness, etc .. Legalities deal with such concepts as what is allowed / not allowed by a society, punishments etc... .

It could be that it only seems to be indeterminate because we do not have enough knowledge of the system. Take a double pendulum for example. If all you can see is the tip of the pendulum swinging under the glare of a strobe light, you could be forgiven for thinking that you are watching random movement that over time obeys a probability wave function. https://en.wikipedia.org/wiki/Double_pendulum#Lagrangian

I think my original question was incorrect - as my concerns are probably with explanations of relativity (such as space-time etc) and not relativity itself. Since it would be incorrect to now re-direct this thread along those lines (and there are a couple of space-time threads currently on-going anyway), I would just like to conclude by thanking everyone for their help on this discussion.

Thanks for spotting that. Even though relativity isn't an explanation (nor does it have to be in order for its equations to work and to be useful), I am still thinking about whether there is a logical contradiction in there somewhere. There is something that doesn't seem to be quite right when trying to apply an explanation of what happens to a clock when it changes from one reference frame to another. But since relativity is not an explanation per se, it could well be that any such issues would be irrelevant to relativity anyway.

I thought it would be easier to follow if I plugged some numbers in! Never mind, in that case best to just ignore those example speeds.

Putting together the above and all the other points people have made to help me, I believe the following shows how two clocks moving relative to each other can both lose time with respect to each other... So that we do not have to worry about clocks accelerating / decelerating, as someone mentioned previously, passing clocks can be used to communicate / compare times. So the stay at home / travelling clock example can be stated like this... The stay at home clock (a) is at rest and a travelling clock (b) flies past the stay at home clock, say from right to left at speed '1s'. As the travelling clock passes the stay at home clock, the two clocks are synchronized. The travelling clock continues on its way to the left at speed '1s'. A second travelling clock ( c ) that is moving from left to right at speed '1s', passes the first travelling clock, and at the moment of passing synchronizes its clock with the first travelling clock. This second travelling clock continues left to right at speed '1s' until it passes the stay at home clock, at which point its time is compared to the stay at home clock's time. It is found that the travelling clock ( c ) has lost time compared to the stay at home clock (a). But who is to say which clock is the 'travelling' clock and which clock is the 'stay at home' clock? To demonstrate that point, here is a slightly extended version of the above scenario... This time, instead of describing the stay at home clock's reference frame as stationary (i.e. speed '0s'), it will be considered to be moving from left to right at speed '0.5s' and the travelling clock (b) moving at speed '0.5s' from right to left. This is still the same scenario as before, as the relative speed between the two clocks is still '1s'. [Any reference frame could be used to state the relative speeds of the clocks, but this one conveniently emphasizes the symmetry between the stay at home clock and the travelling clock.] As before, when the travelling clock (b) passes the stay at home clock (a), the two clocks are synchronized. The second travelling clock ( c ) that is moving from left to right at speed '1.5s', passes the first travelling clock, and at the moment of passing synchronizes its clock with the first travelling clock. The second travelling clock continues left to right at speed '1.5s' until it passes the stay at home clock (a), at which point its time is compared to the stay at home clock's time. It is found that the travelling clock ( c ) has lost time compared to the stay at home clock (a). And to show that it is equally valid to consider that it is the stay at home clock (a) that loses time compared to the travelling clock (b), a fourth clock (d) travelling from right to left at speed '1.5s' can pass the stay at home clock (a) and synchronize its time with the stay at home clock. When this travelling clock catches up with the travelling clock (b) and their times compared, it is found that the stay at home clock (a) has lost time compared to the travelling clock (b). So if I have got the above correct, then what I need to demonstrate is does the above lead to a logical contradiction?