Strange

Length, distance, time, ...

There are many cases where it is not possible to isolate causes and effects and study each independently. In such cases, other approaches are used. Also, time is not an "event", and there is no "force" slowing the clock down, so this feels somewhat irrelevant. And, as always, any objection you raise to the temporal dimension applies equally to the spatial dimensions (which also change in the example you give). But you can't observe length. You can only observe marks on a stick, or more general, distance.

You have clearly demonstrated that you do not have the necessary competence or background knowledge to make any such judgements. That belongs in the other thread. This thread is about your claim that photon emission does not conserve momentum. You need to provide some support for this.

By the way, Bjarne: your thread is now in Speculations so it is time for you to stop asking questions and stop rejecting evidence. It is time for you to produce evidence that conservation of momentum is violated. It is time for you to produce evidence that a force is not produced by the emission of photons. (Which will, of course, require you to provide detailed alternative explanations for all the examples where this fact is observed.)

I rarely disagree with Ophiolite, but in this case I do. I might copy that list and keep it handy for when it is needed.

Hmmm... I read it when you first posted it. And I think I have seen others mention it (but maybe only moderators - maybe only you!) I suspect the "views" count is not very accurate. (I wasn't logged in when I read it; I don't know if that makes a difference.) I think it is a very good summary of the requirements (for both sides). I have already failed to live up to the spirit of it... Must try harder....

Sorry, as you are incapable of reading and deny the sky is blue, I have nothing else to say to you. As Ophiolite noted, "if you have nothing nice to say, don't say anything".

No. And no. It seems more and more certain that anything said by this clown (related to science, at least) can be just ignored. (Just to be clear, "this clown" refers to Deepsit Chapra, not Petrushka!)

Imatfaal provided a 25 page paper on this in post #22. This explicitly shows that emitted photons cause a force. Despite the Nichols radiometer, solar sails, spectroscopy, the Yarkovsky effect, Compton scattering, the Mossbauer effect (which are all solid, practical, hard evidence of the sort you claimed you wanted). It is hard to know how to react to this sort of extreme denialism and wilful ignorance. My little example conversation about the sky being blue was obviously too generous: "What colour is the sky?" "Blue." "How do we know that?" "Look: it's blue" "Yes, but what real hard evidence do we have that it is blue?" "Look at it. Look! It's blue!" "But I am still not convinced. So long as I am not sure that specific experiments have been done. After all, I have personal reasons to think it might not be blue" "Look. Just look. <sobs>" Perhaps you would be happier if we admitted that you are right: it is the unicorns that did it. IKAROS. There is no link in post 37. The Nichols radiometer, solar sails, spectroscopy, the Yarkovsky effect, Compton scattering, the Mossbauer effect are all solid, practical, hard evidence of the sort you claimed you wanted. You just dismiss them because you don't like the results. But you are not even honest enough to say that. You pretend the information isn't there. As they say, keep an open mind, but not so open that your brain falls out. Don't be so modest. You have done a fantastic job of rejecting facts. There should be some sort of award for this level of denialism. There are many other options. But they belong in the other thread.

Well, I can't stop you stopping, obviously. But I am disappointed. (And a little puzzled as to why you think you need to.) You see, that is why I think this is an interesting discussion. I think I (and many scientists) would agree with much of what you say there. Which is why I was pursuing this line of thought. And, again, I largely agree with this. Well, some of it ... Do you mean not allowed in science or not allowed on the forum? That is interesting. I was always under the impression that materialism (and any other philosophical position) is not refutable (nor provable). As you are unwilling to discuss this further I will have to remain under that impression. While I agree with that. I don;t really think it is a prediction in the scientific sense. (Neither would I "dismiss" it.) But what it says is that the subject is not one amenable to scientific investigation (because it doesn't lend itself to quantifiable predictions and objective measurements. I wouldn't expect you to. I was interested in the more general implications for science and, as an extension of that, perhaps getting an understanding of what you think "science" is and does. The only reason it "didn't go well" is because you refuse to discuss anything and because you appear to think any question or comment at all is some sort of personal attack. People put links to further information here all the time. It isn't "advertising". I think you are being ridiculously coy. I'll provide the link for you: http://thisquantumworld.com/wp/ (See, the world hasn't ended.) http://theworldknot.wordpress.com/

We have just had a timely update to the forum rules reminding us all to be polite. However, Your gross dishonesty is truly offensive and makes it quite hard to write this response. But, in short, ALL of the links I provided were to answer specific points that you made. Anyone can look back at your previous posts and see exactly how dishonest your are being. It does not look good. From that page: "The momentum of the radiation causes a reactive force, expressed as a pressure across the radiating surface." How hard is that to understand? No "university math" required. And, being Wikipedia, it included links where you could check that the statement was correct. At this point, I pointed out that the Crooke's radiometer was not relevant and I gave you the link to the Nichol's radiometer because it gave exactly the "hard evidence" you were requesting. You can't blame anyone else but yourself if you were unable to read that very short Wikipedia page. This is not a link to "advanced math". This was another example of the "hard evidence" you requested. The page is about OBSERVED line widths in spectroscopy and the effects that cause it. One of the effects, from that page: "When an atom emits a photon, the atom must recoil to conserve momentum." I quoted that sentence before, and pointed out that it is OBSERVATIONAL EVIDENCE. There is no advanced math involved in reading one short sentence. Again, the failure is yours. You may not have asked for it but it was in response to your claim that the existence of dark matter was not questioned. It very obviously is (because that is what science does). Again, this was in direct response to your ignorant statement that there was no evidence for dark matter. There very obviously is. At this point you have been given one theoretical explanation (from Wikipedia, so dumbed down to be easily understood) and at least four practical examples (you have skipped the solar sail example and the Yarkovsky effect). But you dishonestly chose to ignore all these. I assume you mean post 39. This was where I summarised, again, all the evidence that had already been provided and that you had chosen to ignore. And you weren't given it. However, if you are not smart enough or not well educated enough to understand basic science, whose fault is that? Not mine. Lesson No. 1 in schoolboy science: what you personally find hard to imagine is irrelevant. The universe doesn't care.

They only appear to get further apart in the past because they are moving away. Once you take that expansion into account, you find that the more distant (further back in time) they are, the closer together they are. You could demonstrate this by doing diagrams with galaxies at different distances and times. But you have convinced me that you are not interested in learning (because it might mean you have to change your mind) so I am not going to waste my time on it.

OK. Your problem seems to be the fact we see things further apart than they were in the past. This seems to be because you are not taking into account that the light they emit is being "dragged back" by expansion. I'm not sure this diagram will help (I'm not quite sure it is 100% correct) but ... The galaxies appear farther away then they were when the light was emitted. (Because of expansion.) This also means that they look further apart from each other. And you could populate that with more stars at different ages and convince yourself that the older they are, the further away and further apart they appear.

Sorry, it doesn't work like that. Time and distance are observer dependent. Imagine that you are here on Earth and Alice is in a spaceship travelling at 87% of the speed of light to her new home at Alpha Centauri. You will both agree on measurements of the speed of light, but you will think it is 4 light years (23 trillion miles) to her destination, but she will think the journey is half that distance.

I am not presenting counter-arguments. I am just commenting and attempting to clarify. If I had no interest, I wouldn't be asking. I didn't reject it; sorry if I gave that impression. I just pointed out that such a simple statement is ambiguous, but could be correct for some interpretations. I can imagine that physicists would say that distance is relative, or observer dependent. Or that the units of measurement are arbitrary. But it isn't clear exactly what you mean by "distance is arbitrary" without more context (such as a reference to a physicist using the term). Why not post them here (I have PMs disabled because this is a discussion forum). I'm sure that is true. But, as I say, it is the implications for physics that interest me. Well, I'm not riled up. And I'm not sure why you are. I am walking on eggshells now, trying not to upset you further. I have no idea what we differ about. I am just trying to explore the idea of metaphysics having implications for science. It is a little frustrating that (once again) you seem unwilling to discuss a topic that you brought up. Last time you brought something up and said it was off-topic, I started a new thread because I thought it was an interesting point. Would you like me to do that again? Could you at least answer the question about materialism: do you think that the correctness or otherwise of this philosophical position has implications for physics? I suspect (but I don't know) that this could be a good starting point for me (and maybe you?) to get a clearer idea about the implications for physics you think may exist. And then have an interesting discussion about it.

My general policy is to assume that unreferenced quotes have been invented. So I will ignore this. I think you should ask that in the Pioneer thread. You might find someone who knows or cares about the answer. THERE IS NO SUCH THING AS "CERTAIN KNOWLEDGE". You had better provide some supporting evidence. That is all that is required. And that is why it hasn't made any progress, I suppose. You keep saying that science will not accept anything contrary to "certain knowledge"; and yet there are plenty of examples of science accepting radically new ideas (including several just in my lifetime). So you agree that there is no such thing as "certain knowledge" and that science does accept new ideas? Make your mind up. But you are also appealing to a fallacy known as the "Galileo Gambit"; just because someone's ideas were initially rejected but turned out to be right does not mean that your ideas must be right because they are rejected. Or, as Carl Sagan put it: They laughed at Galileo. But they also laughed at Bozo the Clown. Obviously. That is how science progresses. THERE IS NO SUCH THING AS "CERTAIN KNOWLEDGE". Indeed. As Asimov said, "The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'" See post 39: http://www.scienceforums.net/topic/86724-photons-and-conservation-momentum-split-from-pioneer-anomaly/page-2#entry839932 See post 39: http://www.scienceforums.net/topic/86724-photons-and-conservation-momentum-split-from-pioneer-anomaly/page-2#entry839932

It still has energy (e=mc2). So you could (in principle) create a black hole just from getting photons into less than the Schwarzschild radius. Then you seem to mean something different by the "grid" than I assumed.

A couple of points. The important point is "relatively large amounts of mass". You are talking about very small volumes and therefore very small masses. Secondly, there is no "grid" as a physical thing. So talking of things being separate from it doesn't really make sense. Arguably, a black hole is purely a result of [the curvature of] that notional "grid".

It may be well know, but it isn't a fact. Well, their calculations fit the data. If there is an alternative explanation, then their calculations must be wrong. Otherwise there is no room for an alternative. That's my point: if you have an alternative explanation, then their explanation based on the radiation must be wrong in some way. There is nothing in science that is "certain knowledge". Not even something as fundamental as Lorentz invariance (equivalent to conservation of momentum). That is why people are constantly doing more and more precise tests - because it would be really exciting to show it is wrong. Not really. But there have been many examples of very bright people coming up with new ideas. (Contrary to your claims about the nature of science.) I can't think of a single answer of an "idiot" (a rather offensive term) contributing to science. I doubt that. But, if true, it shows once again that you are wrong. Maybe the theory is wrong. That will be determined by the evidence. That is why people are looking. (Again proving you wrong.) There is no such thing as certain knowledge. (Why do you keep saying this?) The whole basis of science is testing (attempting to break) existing theories. We have just had an entire thread on this subject: it is not the question that is the problem. Anyone can ask questions. It is often said that there is no such thing as a stupid question. It is refusing to accept answers and evidence that is irrational. "What colour is the sky?" "Blue." "Why?" "Raleigh scattering ... blah blah blah ..." "OK, but what if it isn't really blue. What if it just looks blue?" "That is what blue means." "But maybe it isn't blue." repeat ad nauseum

Just because lots of other people repeat the same nonsense, doesn't mean it isn't nonsense. It isn't ugly; it is based on fundamental symmetries of the universe. And you have now been given "hard evidence" and theoretical justification. That might be your problem: the Internet ≠ Science. If you (or someone) comes up with an alternative explanation then that will have to include an explanation of where the Anderson/Turyshev analysis is wrong. That won't be related to the momentum of electromagnetic radiation. But it could be because they have wrongly estimated temperatures, surface characteristics, or incorrectly calculated the effect on the velocity, etc. (I think one of the regular posters here is convinced there are such errors.) Of course. Why would I care? If that analysis is shown to be wrong, then that is how science makes progress. Well, good luck. But you should start with the possible, then try the impossible before resorting to magic. So you dismiss fundamental aspects of physics as "speculation" but latch on to some unconfirmed (*) results as overthrowing "immovable facts". This is pretty irrational. For example: http://arxiv.org/abs/0810.3265

I am sorry you perceive it that way. It isn't intended. I'm not sure what to do about that. (Apart from stop asking questions and I don't want to do that.) Well, quite. That is sort of why I was hoping that some who does know could explain it. Maybe we can make progress if we stick with one point you have made a couple of times: materialism. Do you think that this philosophical view (or its disproof, if such were possible) has any implications for science?

People who have studied evolution.

I would give them an explanation at the level I was able, and that I thought was appropriate for them, and suggest places to more information. (Others here would do a far better job than me in this case!) I don't fully understand all your terminology (knowing little about the subject) but I was calling the sort of (false) dichotomies that you are opposed to unrealistic. I thought that was something we agreed on. But maybe I understand even less of what you say than I think. I am not particularly interested in philosophy (if you will forgive the traditional British understatement) but was very interested in the idea that there might be implications for science. Which, as I say, has nothing to do with (modern) science. I would have thought that was pretty simple: objective, quantifiable predictions from models, which can be tested against measurements. (That is off the top of my head, so I'm sure it could be improved...) Objective, quantifiable predictions from models, which can be tested against measurements. I am going to skip over the stuff about consciousness mainly because it has nothing to do with physics. (And also because it might lead to an argument! I see no great mysteries beyond the bounds of science there.) I can see how the concept of consciousness can appear slippery because it is ill-defined and hard to quantify. But ... again ... I don't see how any of that relates to physics. Maybe. But (with a few exceptions) interpretations of quantum mechanics are not physics. Some of these clearly have no connection to physics (or science in general). For example, "materialism is false". Meh. So what. There are many scientists who believe that already. (Some days I do and some days I don't But then I am not a scientist, so it doesn't matter.) "Distance is arbitrary" is so vague as to be meaningless. It could be consistent with general relativity or it could be an anti-scientific statement that all our measurements are wrong. Who knows. Indeed. For someone who is so convinced that there must be implications for physics, you seem to be struggling to identify them.

Nonsense. Yes you are. But we don't "know" (with that sort of certainty) anything. I can only assume you have been reading poor quality journalism. Even conservation of momentum is not sacrosanct if you can provide evidence. That is why people keep coming up with more and more accurate tests. Nonsense. This is contradicted by the article itself: "their measurements matched the 'magnetic seeds' predicted by theoretical studies" Of course. That is what science does. (Despite your ludicrous claims about "immovable facts".) I don't understand your problem. On the one hand you complain about "immovable facts" (which don't exist) and then you worry that we might discover something new. If more evidence or a better analysis or some new physics is found that results in a better answer, then that will be good news. It is not a religion. No one is worshiping Pioneer. The Anderson/Turyshev work is just a good detailed analysis that fits the facts pretty well. Maybe someone will come up with something better. There is nothing to stop you or anyone else trying to do that. It would be great. You could get a paper published. But sitting there saying "I find physics implausible so I propose ... magic" is not going to impress anybody.

Hey, you know what: when the text is bright blue and underlines it is what we call a "hyperlink". It means you can "click" on the links and they take you to another "page" on the "web" where you can find more information. That "page" might have more "hyperlinks" to further "pages" which have yet more information. This amazing "web" of information is enabled by the success of science and technology (which you think is implausible). For example, this is the Wikipedia page about solar sails: http://en.wikipedia.org/wiki/Solar_sail It inlcudes information about real, practical, functioning solar sails and (wow!) links so you can find even more details about them. I suggest you read some of them instead of just repeatedly typing "I don't believe in science because it is too amazing... I don't believe in science because it is too amazing..." You did mention it before. And I did reply. My reply was that you are mistaken. It is the CROOKE'S radiometer where the movement is due to thermal effects. The NICHOL'S radiometer moves due to radiation pressure. Here is an overview, again from Wikipedia (so there are more references to read up): http://en.wikipedia.org/wiki/Nichols_radiomete There was also the original paper that imatfaal provided a link to. You should read it because they explain the reasons for using mirrored surfaces. http://mesoscopic.mines.edu/mediawiki/images/3/39/Radiationpressure.pdf There was also information on the effect on spectra caused by atoms recoiling when a photon is emitted. http://quantummechanics.ucsd.edu/ph130a/130_notes/node429.html And finally, the Yarkovsky effect: http://en.wikipedia.org/wiki/Yarkovsky_effect I don't know how much more direct evidence you need. Momentum IS conserved. If you are still going to deny this then you will more evidence than "I don't believe it". Only in your head. Presumably because you don't understand what you are saying.