|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
The universe of Mr Tegmark
Max Tegmark "Our mathematical universe"
OK, at least Mr Tegmark doesn't avoid the question: What's our universe expanding into? ---------------------------------- Mr Tegmark writes about this question 16 lines. Some of those lines are wasted with the assurance that no chocks will occur because of space expansion. At least 4 lines reassuring us, poor souls, that no galaxy pileup is around the corner. Well, I am reassured Mr Tagmark. It always amazes me how cosmologists can hide behind words. Almost at the end of the 16 lines, almost as an afterthought Mr Tegmark comes to two "viewpoints". You can see it either as: Static space: Galaxies are receeding faster and faster from us in a static space. Well, static space means that there is NO space expansion, and galaxies are receeding from us at an accelerated rate. Assuming that red shift equals distance this view point leads to an horizon. Parts of the universe are receeding faster than light, in 3 dimensions there is no solution. The other solution is static matter: volume is not constant and new volume "is created", just like that. Obviously space is created when nobody is looking. Space hides when doing this kind of aberrations of course, very shy. Space hides conveniently in "the space between galaxies". Ahh ok. How clear. Imagine I am traveling smoothly between galaxy A and galaxy B. Suddenly, my space ship incrases its volume. Wow! The machine room got bumped left of the motor B22, an empty cube of several meters appeared between two parts of the motor, what made the connexions get loose and the computer to shut down. Ahh this dammed space that can't keep it steady and must bump new space at the worst moments somewhere! Vulgarisation is not just speaking about the questions with *some* seriousness. Obviously Mr Tegmark hasn't done any further thoughts into this particular question than those 16 lines... At least not in that book. A book that tells "the layman" a story like you tell it to a child. Look, laymans like the target audience of this book CAN exist. Do they actually exist? Maybe. But in the laws of big numbers, I would bet that in thousands of laymans about astronomy that buy this book, some of them will be pleased with a straightforward story of how the universe came into being, nice to know, you know? This is all very official, with NASA satellites, etc. Precision cosmology. I am a layman of course, but I do not agree that the answer is 16 lines of nothing really. For me this problem is unanswered by the BB people. The book is in itself interesting because it shows what is really the stand of BBs. "Volume appears", just like that! All this bang disappears if we asssume that (for an unknown reason) light for distant objects gets red-shifted. No Doppler effect, just red-shift, what is something different but not related to some "space expansion". This conceptual advance will allow astronomers to start looking for the reason of the red-shift instead of believing that they know what the red shift is! A VERY important conceptual step that Mr Tegmark doesn't do. [Mod. note: tired light theories have well-known problems and are too speculative to be discussed here -- mjh] |
#2
|
|||
|
|||
The universe of Mr Tegmark
In article , jacob navia
writes: Max Tegmark "Our mathematical universe" OK, at least Mr Tegmark doesn't avoid the question: What's our universe expanding into? Static space: Galaxies are receeding faster and faster from us in a static space. Well, static space means that there is NO space expansion, and galaxies are receeding from us at an accelerated rate. There are indeed various viewpoints in the literature. However, all of them agree regarding observable effects, so it's more a question of what is useful in a given context. Assuming that red shift equals distance this view point leads to an horizon. Parts of the universe are receeding faster than light, in 3 dimensions there is no solution. No. One can have a self-consistent solution in the static-space framework. (Note that neither a horizon nor faster-than-light recession is a problem here.) Obviously space is created when nobody is looking. Space hides when doing this kind of aberrations of course, very shy. Space hides conveniently in "the space between galaxies". Ahh ok. How clear. Imagine I am traveling smoothly between galaxy A and galaxy B. Suddenly, my space ship incrases its volume. Wow! The machine room got bumped left of the motor B22, an empty cube of several meters appeared between two parts of the motor, what made the connexions get loose and the computer to shut down. Calculate how much extra volume must appear in your spaceship in your lifetime. It is not noticeable. Vulgarisation is not just speaking about the questions with *some* seriousness. Obviously Mr Tegmark hasn't done any further thoughts into this particular question than those 16 lines... You probably mean "popularization". I'm sure that he, and others, have put more than 16 lines into this. At least not in that book. A book that tells "the layman" a story like you tell it to a child. The book covers a range of topics, with an emphasis on the multiverse. Certainly among the mainstream stuff, nothing is wrong. More detailed explanations can be found in other books. I am a layman of course, but I do not agree that the answer is 16 lines of nothing really. For me this problem is unanswered by the BB people. You need to find better evidence of a conspiracy than this. All this bang disappears if we asssume that (for an unknown reason) light for distant objects gets red-shifted. No Doppler effect, just red-shift, what is something different but not related to some "space expansion". It is not an unknown reason, but a firm prediction. Learn all you need to know about this and other topics in Edward Harrisons textbook COSMOLOGY: THE SCIENCE OF THE UNIVERSE. He uses the expanding-space picture, but Bunn and Hogg in an American Journal of Physics paper show an equivalent formulation in terms of the Doppler effect. (However, this is more an academic exercise in that in general no cosmological velocity, defined as the change in (some) distance with time, is described by the Doppler formula (relativistic or not). Harrison also wrote an ApJ paper entitled "The redshift-distance and velocity-distance laws", which clears up all confusion. This conceptual advance will allow astronomers to start looking for the reason of the red-shift instead of believing that they know what the red shift is! A VERY important conceptual step that Mr Tegmark doesn't do. Again, the emphasis of Tegmark's book is elsewhere, so one can't expect him to discuss everything in detail, especially not non-controversial mainstream stuff. Please read Harrison's book and the article I mentioned and ask again if you think that there is some problem in this area which cosmologists have got wrong. |
#3
|
|||
|
|||
The universe of Mr Tegmark
On Tue, 08 Jul 14 08:15:09 GMT, Phillip Helbig---undress to reply
wrote: The redshift-distance and velocity-distance laws You say we should read Harrison's article, but what can you really learn from a verbose article like this? What are we to make of an equation for the distance to a co-moving body where the units are so far out of balance: (where c must be the speed of light R is dimensionless) L = cR_0*r meters? section 6.2 I don't see how this is a useful equation and the failure to balance units makes us doubt any of the other results John Polasek |
#4
|
|||
|
|||
The universe of Mr Tegmark
In article , news
writes: The redshift-distance and velocity-distance laws You say we should read Harrison's article, It is one of the best on the topic. but what can you really learn from a verbose article like this? A wealth of information. What are we to make of an equation for the distance to a co-moving body where the units are so far out of balance: (where c must be the speed of light R is dimensionless) L = cR_0*r meters? section 6.2 Some authors have the scale factor dimensionless. Others prefer it to have a dimension and express "distance" via a dimensionless quantity, which has the advantage that such comoving distances do not change when the universe expands (the physical distance is the coordinate distance times the scale factor). However, you can be sure that Harrison's treatment is consistent and that he has not made a simple error such as an equation where the dimensions don't match. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
The Observed Universe, Our Universe, Our Big Bang. | Nicolaas Vroom | Research | 22 | July 22nd 14 06:29 PM |
can solid-body rotation alone prove the Universe is an atom? #131;3rd ed; Atom Totality (Atom Universe) theory | Archimedes Plutonium[_2_] | Astronomy Misc | 1 | August 9th 09 05:57 AM |
Finite Universe - Infinite Universe. | G=EMC^2 Glazier[_1_] | Misc | 0 | June 16th 09 01:09 PM |
Infinite Universe versus volatile Universe | G. L. Bradford | Policy | 3 | June 21st 06 12:49 PM |
parllel universe have diffrent speed of light 128 168 300 299 thats how you find diffrent universe i'm from the planet earth that is the 7th from the sun stuck on one that the planet is 3rd from the sun the speed of light is 128 and 32 dimentions | Roger Wilco | Misc | 1 | December 30th 03 11:15 PM |