Hi Peter,

Thanks very much for your comment. I look forward to reading your essay.

Best,

Amanda

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Hawking assumes the speed of light is constant in a gravitational field (and so contradicts both general relativity and Newton's emission theory):

Stephen Hawking: "Both Mitchell and Laplace thought of light as consisting of particles, rather like cannon balls, that could be slowed down by gravity, and made to fall back on the star. But a famous experiment, carried out by two Americans, Michelson and Morley in 1887, showed that light always travelled at a speed of one hundred and eighty six thousand miles a second, no matter where it came from. How then could gravity slow down light, and make it fall back."

Stephen Hawking, A Brief History of Time, Chapter 6: "Under the theory that light is made up of waves, it was not clear how it would respond to gravity. But if light is composed of particles, one might expect them to be affected by gravity in the same way that cannonballs, rockets, and planets are.....In fact, it is not really consistent to treat light like cannonballs in Newton's theory of gravity because the speed of light is fixed. (A cannonball fired upward from the earth will be slowed down by gravity and will eventually stop and fall back; a photon, however, must continue upward at a constant speed...)"

Do you agree with Hawking? Is the speed of light constant in a gravitational field? Did the Michelson-Morley experiment show "that light always travelled at a speed of one hundred and eighty six thousand miles a second, no matter where it came from"?

Pentcho Valev

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Dear Ms Gefter,

You are welcome.

ps:The observation permits to improve the knowledges. The dynamics seem universal at all 3D scales. A hymenoptera(a bee) see the same dynamic with a pure relativity. If on an exoplanet, some intelligent creations see, they see the same relativistic dynamic of rotations of spheres. If a bird flies, so it utilizes the same physical laws, like made an airplane. In fact it is the same for all lifes in fact and all dynamics, so all rotations and motions implying rules of complementarity of evolution. The observations everywhere inside our universal sphere shall be always under the same universal dynamic of spherization in fact. The Universe is unique and bounded, with a specific universal equation of spherization of spheres.

I beleive strongly that in fact the importance is to differenciate the philosophical interpretation(multiverse) and the pure realistic determinism of uniqueness and the correlated intrinsic laws(Universe).

Fortunaly for our equations, laws, constants and SI :) furthermore. If not, we violate our laws, physical and universal of this homogene and intrinisic and bounded spacetime.

Best Regards

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Thanks for this provocative and persuasive argument. The notion that reality may be observer-dependent by virtue of it being tied to perception which is necessarily user-specific leads me to wonder if what actually IS can ever be truly known. Also, I wonder if what actually is could be subject to the Hawthorne effect (from the social sciences, I think) whereby that which is being observed changes as a result of efforts to observe it. And then what?

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Dear Amanda,

a very relevant, well written essay. Good luck.

    Dear Amanda:

    What a nice and provocative essay.

    I have one, very basic, question: For concreteness I will focus on the question of observer dependence of the notion of particles. If one looks at Unruh's calculation that gives a thermal spectrum of particles for the accelerated Rindler observer and no particles for the Minkowski observer isn't it true that the calculation starts from the same state in the same space-time for both these observers? While it is true that the two descriptions by the two observers are different it is also true that there is one description from which both of these can be derived.

    So why shouldn't I call this one description (Minkowski space R^4 together with vacuum state |0>) the one universe? If you want the description for a particular observer just tell me how she moves and I will tell you what she sees.

    I think what I said here for particles remains true for the other examples you cite (with the possible exception of quantum mechanics).

    All the best.

    Olaf

      Hi Olaf,

      Thanks so much for taking the time to read my essay, and for your great question.

      I agree with you that in the Rindler case, you can think about two observers that start in the same universe, then have radically different but equally correct views of that same universe (rendering particles observer-dependent). As you say, you can translate between them (with a Bogoliubov transformation rather than a Lorentz transformation). That alone doesn't obviously demonstrate the solipsism I'm arguing for, though the observer-dependence of the vacuum (with none being more "true" than another) is kind of the first clue that there is some degeneracy in the nature of the universe. But take the case of an elephant falling into a black hole. An accelerated observer outside the black hole will see the elephant burn up before it crosses the horizon, its ashes radiated back out to infinity. But an inertail observer who falls in with the elephant sees it alive and well inside the black hole before it hits the singularity. If you assume that these two observers occupy one single universe, then it's a universe in which the elephant's quantum state has been cloned, violating the laws of quantum mechanics. If you want to keep the laws of physics intact, you're forced to give up the notion of a single, shared universe and instead restrict to a single observer's frame. I suspect there's a way to make this same argument for a Rindler observer, but it's not as intuitive, since he can always stop accelerating, rejoin the inertial observer and compare notes. Nonetheless, while he is accelerating you would surely violate the laws of physics if you described both their points of view with a single global geometry. This becomes especially relevant when you consider that we live in an asymptotically de Sitter universe, and that each observer has their own event horizon.

      To my mind, this tells us something very powerful. That's not an original insight - I am taking cue from Susskind, Bousso, Banks, etc. Banks in particular argues that we have to generalize this argument to say that physics only makes sense within a single causal patch and that everything outside that observer's horizon should be considered pure gauge. What's original (and undoubtedly controversial!) in my piece is the attempt to connect this view with the low quadrupole in the CMB and with quantum logic.

      Thanks again.

      All best,

      Amanda

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      With not long to the end of community voting your consideration of my own would be very much appreciated. Kind regards Georgina.

      This is a very original and thought provoking idea, good luck.

      • [deleted]

      Did you rate my essay?

      Dear Amanda

      Very interesting essay! Thanks for the suggestion! Now I could for the first time understand some of the basic ideas about the problem of information in black-holes. But I have a question, if the universe is not shared by all the observer, what is shared by all observers?

      I have some ideas about it that can possibly give you some insight, well I hope so... One of the main problem was that apparently there was information being cloned if you look from to observers at the same time. However, there should be some correlation between any two observers. In this case, the total entropy (or information) will not be the sum of each observer's entropy. Actually I think two observers are completely correlated such that their total entropy equals each one' entropy. This might explain why "we can never speak about more than one at a time." and also why "according to which each observer's reference frame defines a complete universe, and anything outside the frame is considered merely a redundant description.". In information theory, if you add a redundant description the information content is not increased!

      I also agree that the existence of more than one reference frame can lead you to non compatible Boolean logics, each frame has a Boolean logic but the comparison cannot be done using a Boolean logic. But I think this notion is different from the notion of quantum mechanics. I mean, your ideas add something new to quantum mechanics (general relativity reference frames and observers), so they cannot be explained by pure QM, we'll need something new, probably quantum gravity or quantum general relativity.

      Wish you all the best! And good luck on this contest!

      Frederico

      Dear Amanda,

      I liked very much your New Scientist article about mathematics and reality, especially the part about the dodecahedron, it is our consciousness but not in our reality. Tegmaark has some points, especially with the limits of our causal universe and the math's that go untill these limits, it is furtheron that our consciousness takes over and goes ad infintum.

      It was Benjamin Dribus who draw again my attention on your essay (I posted before (september 10) in a post on [link:fqxi.org/community/forum/topic/1370] my thread [/LINK] , regarding the aspect of subjective reality that we both are treating.

      I understand you are very busy, but perhaps you will find a split moment to read and or rate (or comment) my participation.

      best regards

      Wilhelmus

      Hi Amanda -

      I came across this paper today. It's too technical for me, but if you haven't already seen it I think you'll be interested in the introductory section -- as a way of thinking about how the different universes of different observers are connected.

      The Principle of Relative Locality

      Conrad

        Amanda,

        I'd like to pass you a link to the paper I referred above with strong analogies to your work, if you have time to read it and discuss.

        I hope you manage to read my essay first as I look forward to your comments.

        Best wishes

        Peter

        Dear Amanda,

        The New Scientist special issue "WHAT IS REALITY" is very good, the perceptions of Henry Stapp and Matthew Donald have a lot of paralels with my own perception of reality.

        I would like to sent my essay to them, is it possible that you give me their e-mail ,

        mine is

        wilhelmus.d@orange.fr

        If not possible, I understand, but a question is always possible.

        Thanks

        Wilhelmus

        Dear Amanda,

        Wow! Your essay deserves the highest possible note -- and you got a 10 from me -- because it brilliantly explores (In the right direction!) which of our basic physical assumptions are wrong. Many thanks to Ben Dribus, who told me yesterday evening about your excellent essay.

        So I would not argue with you when you "... argue that the basic assumption of a single universe shared by multiple observers is wrong." On the contrary, I fully agree with your perspective, and in my essay From Minkowski's Diagram to the Multispace Model of the Universe I make the first step in the same direction by explaining "why" and most important "how" it happens that this universe is a multispace.

        Yes, as you say, "... each observer lives in their own unique universe", but I realized that telling this fact like that was quite scary for some people, and that they had a tendency to disconnect themselves from my subject. Didn't you notice the same thing?

        So in my essay, I preferred to use 'spacetime reference frames' instead of 'universes' and 'multispace' instead of 'multiverse,' nicely reminding the audience that this confirms Minkowski's 1908 declaration that the world is composed of an infinite number of spaces, as well as his multispace relativity.

        You say "that we must never speak of more than one observer or universe at a time."

        On one side, I completely agree. Each observer exists in his own universe. It is not for nothing that we instinctively feel we live in a 'bubble of perception.' And it's also true that we perceive the surrounding reality through our sense organs, filters that project this reality into our 'bubble universe,' our conscious self. So yes, each of us is 'one observer in his own universe.'

        Yet, on the other side, it's not so simple. When do we start to talk about this 'own unique universe?' Is it the space surrounding our body? If you and me are ten feet away are we still in the same universe? What if we hug each other? If I look at my hand, is it inside or outside my universe?

        Even more, we agree that in a multispace/multiverse world, "... each observer lives in their own unique universe." But each observer -- in fact each of us -- is made out of various organs, cells, and so on until these nagging pieces of matter called elementary particles. Do we have the right to say that quantum spaces are also little universes? After all, besides the size, the only difference between me looking at you through our universes, and seeing you, and looking at an elementary particle through its universe -- its quantum space -- is that I don't see this elementary particle. But there is a simple and very physical explanation for that, which I also advance in my essay From Minkowski's Diagram to the Multispace Model of the Universe.

        In fact, what I want to say is that this essay is just the tip of the iceberg. I spent several years to prove the Multispace Model beyond any possible doubt by finding convincing supportive evidence not just in physics, but also in cosmology and in Earth sciences.

        I hope you have a moment to check it out and share your thoughts with me.

        Best of luck in the contest.

        Eugeniu Alexandrescu

        If you do not understand why your rating dropped down. As I found ratings in the contest are calculated in the next way. Suppose your rating is [math]R_1 [/math] and [math]N_1 [/math] was the quantity of people which gave you ratings. Then you have [math]S_1=R_1 N_1 [/math] of points. After it anyone give you [math]dS [/math] of points so you have [math]S_2=S_1+ dS [/math] of points and [math]N_2=N_1+1 [/math] is the common quantity of the people which gave you ratings. At the same time you will have [math]S_2=R_2 N_2 [/math] of points. From here, if you want to be R2 > R1 there must be: [math]S_2/ N_2>S_1/ N_1 [/math] or [math] (S_1+ dS) / (N_1+1) >S_1/ N_1 [/math] or [math] dS >S_1/ N_1 =R_1[/math] In other words if you want to increase rating of anyone you must give him more points [math]dS [/math] then the participant`s rating [math]R_1 [/math] was at the moment you rated him. From here it is seen that in the contest are special rules for ratings. And from here there are misunderstanding of some participants what is happened with their ratings. Moreover since community ratings are hided some participants do not sure how increase ratings of others and gives them maximum 10 points. But in the case the scale from 1 to 10 of points do not work, and some essays are overestimated and some essays are drop down. In my opinion it is a bad problem with this Contest rating process. I hope the FQXI community will change the rating process.

        Sergey Fedosin

        Please make note of this correction:

        In my essay's section on holographic spacetime, I attributed the theory to Tom Banks. However, it should have been attributed to Willy Fischler as well. My apologies for the omission.

        Many thanks,

        Amanda

        5 days later