Alan McDougall Posted January 9, 2014 Posted January 9, 2014 http://www.space.com/24207-dark-energy-galaxy-map-aas223.html The new results, presented by Schlegel and his colleagues here today (Jan. 8) at the 223rd meeting of the American Astronomical Society, also provide one of the best-ever determinations of the curvature of space, researchers said. In short, the universe appears to be quite "flat," meaning that its shape can be described well by Euclidean geometry, in which straight lines are parallel and the angles in a triangle add up to 180 degrees. "One of the reasons we care is that a flat universe has implications for whether the universe is infinite," Schlegel said. "That means — while we can't say with certainty that it will never come to an end — it's likely the universe extends forever in space and will go on forever in time. Our results are consistent with an infinite universe." BOSS astronomers use a spectrograph on the Sloan Foundation's 2.5-meter telescope at Apache Point Observatory in New Mexico to make their observations. "On a clear night when everything goes perfectly, we can add more than 8,000 galaxies and quasars to the map," Kaike Pan, who leads the team of observers working with the spectrograph, said in a statement. The team has presented other results from the galaxy survey. However, the new map extends the survey's reach, more than doubling the size of the examined area and thereby allowing for more precise measurements. The newly presented data also include earlier results that surveyed nearby galaxies, BOSS officials said. "Making these measurements at two different distances allows us to see how the expansion of the universe has changed over time, which will help us understand why it is accelerating," explained University of Portsmouth astronomer Rita Tojeiro, who co-chairs the BOSS galaxy clustering working group along with Jeremy Tinker of New York University. The new results should help lay the foundation for even more-precise measurements in the coming years, Schlegel said. "Future surveys will be doing more of this, both filling in this map of the universe, [and] the enormous volume of the universe we have yet to map out and doing this with even higher precision," Schlegel said here today at the AAS meeting. Interesting!
pantheory Posted January 11, 2014 Posted January 11, 2014 I think they finally have a firm grip on reality after almost 9 decades of false thinking. I still think they are missing the final piece of the puzzle concerning what space really is however. The question becomes: what would the meaning of space be in the total absence of matter and field? The seemingly obvious answer is that space would be meaningless without something to compare it with. Bottom line, I believe, is that space must be defined as simply the distance between matter and the volume that matter occupies. Any hypothetical volume outside of all matter, and with the total absence of everything else, it seems to me, could be no more than a foolish imagination of unreality
Alan McDougall Posted January 11, 2014 Author Posted January 11, 2014 (edited) I think they finally have a firm grip on reality after almost 9 decades of false thinking. I still think they are missing the final piece of the puzzle concerning what space really is however. The question becomes: what would the meaning of space be in the total absence of matter and field? The seemingly obvious answer is that space would be meaningless without something to compare it with. Bottom line, I believe, is that space must be defined as simply the distance between matter and the volume that matter occupies. Any hypothetical volume outside of all matter, and with the total absence of everything else, it seems to me, could be no more than a foolish imagination of unreality Astrophysics differentiate in their definition of space and that of an empty void, they imagine them as two different things. As for me I also don't know exactly what spacetime really is, but the analogy of sort of fabric, satisfies me until someone comes up with an exact description of the reality we call spacetime Edited January 11, 2014 by Alan McDougall
pantheory Posted January 11, 2014 Posted January 11, 2014 Astrophysics differentiate in their definition of space and that of an empty void, they imagine them as two different things. As for me I also don't know exactly what spacetime really is, but the analogy of sort of fabric, satisfies me until someone comes up with an exact description of the reality we call spacetime Yes, many or most theorists believe that the Zero Point Field embodies all of an infinite space, but that idea leads to the BB not being the beginning of everything (not saying that it was ). I believe a far simpler concept and explanation would be that the Zero Point Field is also limited in its extension like space, beyond which would be "non-existence" of anything, not even space. Again I think that space is best understood as the volume which matter and field occupies and nothing more. I expect what they now think is granularity of space of some kind is instead a simple type of finite aether, or if one prefers modern hypothesis, a finite quantity of dark matter or a finite Higgs field. With the revelation that space appears to be totally flat within the capabilities of our present observational capabilities at the farthest distances, and whether space can expand, bend, warp, etc. as in GR, I also think will be seriously challenged in the next decade if not sooner. I don't think René Descartes was too far off when he described space as an extension of matter.
Strange Posted January 11, 2014 Posted January 11, 2014 As for me I also don't know exactly what spacetime really is, but the analogy of sort of fabric, satisfies me until someone comes up with an exact description of the reality we call spacetime I think "fabric" is a very misleading analogy. On another forum someone came up with this (I'm sure he won't mind me pinching it): Space-time to me is simply a manifold at each point of which one can perform physical measurements with clocks, rulers and accelerometers. The curvature of space-time is simply how measurements at one point are related to measurements at another point. I do not think of it as some kind of "fabric" that is being stretched or distorted or whatever - do so leads to many misconceptions. If you want, you can picture space-time as a matrix of clocks connected by rulers, and examine what these clocks and rulers actually read. In other words it isn't "space" that is curved (after all, it doesn't exist) it is the lines (geometry) connecting points in space and time that are curved. Yes, many or most theorists believe that the Zero Point Field embodies all of an infinite space, but that idea leads to the BB not being the beginning of everything (not saying that it was ). "Embodies" is an odd choice of word. Even "pervades" would be odd, but perhaps more accurate. The zero point is just a statement of the fact that the minimum energy of empty space is non-zero. And I don't see why this value has any relevance to the big bang theory; it is a purely quantum effect.
Alan McDougall Posted January 11, 2014 Author Posted January 11, 2014 I think "fabric" is a very misleading analogy. On another forum someone came up with this (I'm sure he won't mind me pinching it): In other words it isn't "space" that is curved (after all, it doesn't exist) it is the lines (geometry) connecting points in space and time that are curved. "Embodies" is an odd choice of word. Even "pervades" would be odd, but perhaps more accurate. The zero point is just a statement of the fact that the minimum energy of empty space is non-zero. And I don't see why this value has any relevance to the big bang theory; it is a purely quantum effect. Very informative comments, thank you!
pantheory Posted January 11, 2014 Posted January 11, 2014 (edited) Strange, "Embodies" is an odd choice of words Yes, maybe not my exact intent of meaning. I probably should have said: I think that many or most theorists believe that the Zero Point Field/Energy is contained within an infinite quantity of space -- and that infinite space would embody an infinite Zero-Point-Field. Although I think the Zero-Point-Field exists throughout space at the macro-scale as well as the micro-scale, I expect it is just that the quantum scale is the only venue to-date that we have definitely recognized it. I also expect that both space and time will eventually be recognized as the simplest of all concepts -- both no more than simple definitions. I hope I will live long enough to see it finally recognized that reality is the place that I believe it to be -- very contrary to most modern physics, more like 19th century physics. My thinking parallels old sayings by Rutherford, "if you can't explain your physics to a bar-maid it is probably not very good physics." Rutherford liked to be crusty from time to time so he also said: "Physics that you can't explain to a bartender is probably no damn good." Alan McDougall, "......but the analogy of sort of fabric, satisfies me until someone comes up with an exact description of the reality we call spacetime " I think Einstein provided a good insight into a logical understanding of space-time when he said: "When forced to summarize the general theory of relativity in one sentence: Time and space and gravitation have no separate existence from matter." - Albert Einstein Below, I believe, is possibly the simplest explanation, but at least a valuable insight into space-time, IMO Space-time, like both space and time, is a simple indispensable concept, especially concerning the math of it. The following may be the simplest verbal explanation of it:: A point in cosmic space can be described in many different ways. In astronomy there are primarily two ways. One is the Cartesian geometry system using X,Y, & Z coordinates, and the other involves astronomical distances from us and triangulated angles from nearby reference stars or galaxies. Both require a coordinate system starting point. This is the problem. Although these systems may at first seem accurate based upon these reference points, it can be realized that we as well as the reference stars or galaxies are moving along with the point in space we are trying to locate. After all of these relative motions are estimated we also can consider that the distant background of galaxies as well as the micro-wave background are generally thought to be stationary and therefore may also be a good reference frame. So how can we fit this all together mathematically? We have to include time as a forth dimension since all our reference points are moving in some way relative to each other and relative to the background considered stationary. With this inclusion of time in the equations as relative movement continues forward in time, this movement can be calculated (estimated) for a future time and therefore the results of our calculations to determine what we may consider "an exact point in space at an exact point in time." Easy breezy. So at its most fundamental level one could define space-time as a simple necessary concept to explain/ calculate a point in space at any given point in time. This can be explained and understood by many barmaids, if not most, right ? In my opinion this is all there is to the concept of space-time. Of course if it really warps, bends, expands, accelerated expansion, etc. as in present theories of it, then it is certainly not a simple thing. But all these complicated concepts including the present perspectives of the meanings of GR, space, and time, I think in time, will greatly be simplified into explanations more like the ones I have given IMO. Edited January 11, 2014 by pantheory
AndresKiani Posted January 12, 2014 Posted January 12, 2014 Just reading you guys' comments in interest. I've wandered this myself, "What is space"?
michel123456 Posted January 12, 2014 Posted January 12, 2014 (edited) Just reading you guys' comments in interest. I've wandered this myself, "What is space"? That is not the right question. I think they finally have a firm grip on reality after almost 9 decades of false thinking. I still think they are missing the final piece of the puzzle concerning what space really is however. The question becomes: what would the meaning of space be in the total absence of matter and field? The seemingly obvious answer is that space would be meaningless without something to compare it with. Bottom line, I believe, is that space must be defined as simply the distance between matter and the volume that matter occupies. Any hypothetical volume outside of all matter, and with the total absence of everything else, it seems to me, could be no more than a foolish imagination of unreality Yes. The right question is: What is distance? Edited January 12, 2014 by michel123456
pantheory Posted January 12, 2014 Posted January 12, 2014 Him michel123456, "That is not the right question." Yes. The right question is: What is distance? I think most realize that distance is a relative measurement related to the meaning of space, but I think present measurements of it concerning cosmic distances and calculated brightnesses, are very incorrect via the Hubble formula, hence the conclusion of dark energy. If "distance" is a relative measurement based upon yardsticks of some kind, which I believe it is, then we would have to consider the merits of the yardsticks being used. What are your thoughts on this?
Alan McDougall Posted January 12, 2014 Author Posted January 12, 2014 (edited) Just reading you guys' comments in interest. I've wandered this myself, "What is space"? The space or void between two objects! Edited January 13, 2014 by Alan McDougall
pantheory Posted January 13, 2014 Posted January 13, 2014 (edited) The space or void between to objects! also AdresKiani, Yes, I think there is no more meaning to space than the distance between two objects as you mentioned, and/ or the volume that all matter collectively occupies. But with GR proposing that space warps or bends, that space expands according to the BB model, that the expansion of space accelerates according to the dark energy hypothesis -- If any of these concepts, theories, and hypothesis have validity, then one might expect that space would necessarily be more complicated than these simple concepts and definitions just given. On the other hand if space is flat at both the largest and smallest scales, and if space does not expand, warp, bend, accelerate etc., then present theory and hypothesis will eventually be proven to be wrong, and only then could time and space be considered the simple concepts that I believe them to be. Edited January 13, 2014 by pantheory
Rajnish Kaushik Posted January 13, 2014 Posted January 13, 2014 space time is 3D not flat and really infinite
Alan McDougall Posted January 13, 2014 Author Posted January 13, 2014 also AdresKiani, Yes, I think there is no more meaning to space than the distance between two objects as you mentioned, and/ or the volume that all matter collectively occupies. But with GR proposing that space warps or bends, that space expands according to the BB model, that the expansion of space accelerates according to the dark energy hypothesis -- If any of these concepts, theories, and hypothesis have validity, then one might expect that space would necessarily be more complicated than these simple concepts and definitions just given. On the other hand if space is flat at both the largest and smallest scales, and if space does not expand, warp, bend, accelerate etc., then present theory and hypothesis will eventually be proven to be wrong, and only then could time and space be considered the simple concepts that I believe them to be. Maybe the space or void between two object at a specific moment of relative time? I think most realize that distance is a relative measurement related to the meaning of space, but I think present measurements of it concerning cosmic distances and calculated brightnesses, are very incorrect via the Hubble formula, hence the conclusion of dark energy. If "distance" is a relative measurement based upon yardsticks of some kind, which I believe it is, then we would have to consider the merits of the yardsticks being used. What are your thoughts on this? Has there been any experiments or test to prove or disprove the Hubble red shift accuracy?
pantheory Posted January 13, 2014 Posted January 13, 2014 (edited) Alan McDougal, Maybe the space or void between two object at a specific moment of relative time? Yes, this could be a definition of a specific or changing quantity of space at a specific location. Has there been any experiments or test to prove or disprove the Hubble red shift accuracy? Theorists now know that the Hubble distance formula does not accurately calculate cosmic distances. Up to a redshift of .5, for instance, distances are now believed to be greater than the Hubble formula calculates. This was discovered by observations of type 1a supernovae. To explain this and other observations the dark energy hypothesis was proposed. As an alternative to dark energy, I and another theorist have reformulated the Hubble formula/ equation based upon a different cosmological model. The scientific paper is still in the peer review process of editing but I expect it to be published in February or March 2014, in the Journal of Applied Physics Research, by the Canadian Center of Science and Education. This site is a Science-News site on a different subject so no further discussion of this Hubble formula topic in this thread would seem appropriate. After publication I may ask permission to post this paper in this forum in an appropriate sub-forum. For some other science Forums posting your own peer reviewed-papers is not acceptable. This paper would probably be difficult reading for a non-astronomer or even for physicists having no background knowledge of supernovae observations. Edited January 13, 2014 by pantheory
swansont Posted January 13, 2014 Posted January 13, 2014 space time is 3D not flat and really infinite Flatness refers to how close to a Cartesian geometry it is. Flat vs curved, as opposed to 2D vs 3D.
michel123456 Posted January 13, 2014 Posted January 13, 2014 (edited) First of all Spacetime is 4D, not 3D. Secondly, distance is not only "the void between two objects" Distance has a lot of "strange" properties. For example take a lever and use the distance to transform the applied force. Take a balance and use the distance to make the balance shift on one or the other side, changing only and only the distance. Take a clock and use it to define distance. Use distance to look in the past. My thoughts about distance are oriented in various directions. Also if you want to change the distance beween 2 objects at rest relative to each other: you need a force to do that. Isn't that mind blowing? Also: you change the distance between 2 objects and the gravity between those 2 objects changes, isn't that fantastic? And not only that, gravity doesn't change in relation to the distance, but respectively to the square of the distance. That is absolutely incomprehensible: what is a distance squared? When we don't even know what a distance clearly "is". Edited January 13, 2014 by michel123456
Alan McDougall Posted January 13, 2014 Author Posted January 13, 2014 (edited) First of all Spacetime is 4D, not 3D. Secondly, distance is not only "the void between two objects" Distance has a lot of "strange" properties. For example take a lever and use the distance to transform the applied force. Take a balance and use the distance to make the balance shift on one or the other side, changing only and only the distance. Take a clock and use it to define distance. Use distance to look in the past. My thoughts about distance are oriented in various directions. Also if you want to change the distance beween 2 objects at rest relative to each other: you need a force to do that. Isn't that mind blowing? Also: you change the distance between 2 objects and the gravity between those 2 objects changes, isn't that fantastic? And not only that, gravity doesn't change in relation to the distance, but respectively to the square of the distance. That is absolutely incomprehensible: what is a distance squared? When we don't even know what a distance clearly "is". The distance between two object in a 3 dimensional void at a specific relative moment,I think is an adequate description of space, not Spacetime, which I agree has 4 dimensions. Distance is also not a static thing , everything in the universe is moving relative to everything else, thus my statement that the distance between two objects in a void can only be correct at the exact moment of time relative to the two objects in question. Then we are left with the enigma of exactly what a moment in time is and if such a thing exists in really , it become more of a philosophical question than one of pure physics . All those statements you say are mind blowing or fantastic are not they are just the the reality in which our universe operates.You also that the physics around gravity and the square of gravity are absolutely incomprehensible, not so many people find this comprehensible. Distance does not give us a peek into the past, it is the finite speed of light that allows that illusion Keep with your sense of wonder and awe about the universe and how it operates Albert Einstein.quoted once that without mystery things could become bland and uninteresting (not his exact quote), I will look it up) Here it is his actual quote! “The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science. He to whom this emotion is a stranger, who can no longer pause to wonder and stand rapt in awe, is as good as dead: his eyes are closed.” Edited January 13, 2014 by Alan McDougall
swansont Posted January 13, 2014 Posted January 13, 2014 And not only that, gravity doesn't change in relation to the distance, but respectively to the square of the distance. That is absolutely incomprehensible: what is a distance squared? In general it's an area, and one can view gravitational field strength in terms of flux line concentration, i.e. number of flux lines per unit area, which has a fairly simple geometric explanation. 1
Alan McDougall Posted January 13, 2014 Author Posted January 13, 2014 In general it's an area, and one can view gravitational field strength in terms of flux line concentration, i.e. number of flux lines per unit area, which has a fairly simple geometric explanation. My point exactly!
IM Egdall Posted January 14, 2014 Posted January 14, 2014 Back to the original link. Latest observations indicate "the universe appears to be quite flat." They are talking about the observable universe being flat. We can only see that part of the overall universe where light from stellar objects has had time to reach us. I think our best understanding is that there may be an overall non-flat curvature to the universe, e.g positive or negative. Inflation has enlarged the universe exponentially, so the part we can see appears to be very close to flat. An analogy is a balloon blown up to stupendous size. We ants on its surface see only a tiny portion -- which appears flat to us. So you cannot just assume the entire universe is flat. We just don't know. 1
Alan McDougall Posted January 14, 2014 Author Posted January 14, 2014 Back to the original link. Latest observations indicate "the universe appears to be quite flat." They are talking about the observable universe being flat. We can only see that part of the overall universe where light from stellar objects has had time to reach us. I think our best understanding is that there may be an overall non-flat curvature to the universe, e.g positive or negative. Inflation has enlarged the universe exponentially, so the part we can see appears to be very close to flat. An analogy is a balloon blown up to stupendous size. We ants on its surface see only a tiny portion -- which appears flat to us. So you cannot just assume the entire universe is flat. We just don't know. I think most astrophysicists support the idea of a flattish universe, but don't take that as gospel just I must check it out because the source of my statement is from my fallible memory.
IM Egdall Posted January 14, 2014 Posted January 14, 2014 I'd say, based on the evidence, that most astrophysicists support the idea of a flat observable universe. Again whether the entire universe beyond what we can see is flat is an open question. For example, in his book, A Universe from Nothing, Lawrence Krauss proposes that the entire universe may be positive curvature -- a closed universe. He says a closed universe has a total energy of zero, hence "a universe from nothing". Inflation expanded this closed universe exponentially, so what we observe in our tiny part of the universe today is nearly zero curvature or flat. Krauss says he based this idea on quantum gravity theory, which, as far as I know, has no supporting evidence. So I think his idea of a universe from nothing remains speculation. 2
Alan McDougall Posted January 14, 2014 Author Posted January 14, 2014 I'd say, based on the evidence, that most astrophysicists support the idea of a flat observable universe. Again whether the entire universe beyond what we can see is flat is an open question. For example, in his book, A Universe from Nothing, Lawrence Krauss proposes that the entire universe may be positive curvature -- a closed universe. He says a closed universe has a total energy of zero, hence "a universe from nothing". Inflation expanded this closed universe exponentially, so what we observe in our tiny part of the universe today is nearly zero curvature or flat. Krauss says he based this idea on quantum gravity theory, which, as far as I know, has no supporting evidence. So I think his idea of a universe from nothing remains speculation. I know this statement might be silly, but unimaginably colossal curved closed universe, would look flat unless one had some way to actually measure or observe its enormity from a distance.
Lightmeow Posted January 14, 2014 Posted January 14, 2014 This might be stupid to say, but what if the universe is really expanding more than the speed of light. If it is going faster than the speed of light, and nothing travels faster than light, then we wouldn't be able to observe the expansion, therefor calling space infinite. That's just want I thing. I can't imagine something infinite. But then, if space isn't infinite, then what is holding space, or the multiverse? Very confusing subject...
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