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From: Martin Brown on 7 Jan 2010 11:09 John Fields wrote: > On Wed, 06 Jan 2010 03:54:02 GMT, J Thomas <jethomas5(a)gmail.com> wrote: > >> John Fields wrote: >> >>> The reality is that galaxies are receding from us at velocities which >>> increase as their distances from us increase, and that they're >>> accelerating, while the theory is that that can't happen because there's >>> no gravitational force which can power the acceleration if the universe >>> started with a big bang. That isn't a correct interpretation of the Einstein field equations as applied to Lemaitre universes. The equation and its solutions do include the possibility of acceleration at cosmological distance scales. It wasn't expected to be seen but the observational evidence for it from supernovae and structural analysis of CMB against galaxy statistics suggests that Einsteins biggest mistake may not be a mistake after all. http://www.space.com/scienceastronomy/astronomy/universe_expansion_020320.html If it had just been the supernova evidence I would personally have preferred to believe there was something slightly odd about early massive star supernova that prevented them being ideal standard candles. AFAIK That possibility cannot as yet be ruled out. >>> Consequently, my argument was, and is, that since the creation of a >>> universe from a putative "big bang" cannot explain the anomalous >>> acceleration of galactic red shift with distance, then perhaps there was >>> no big bang, but rather a big bubble at the beginning of time which does >>> allow galactic red shift acceleration with distance. >>> >>> Do you have a better idea? Big Bang is just a name given to the set of cosmologies which are radically different from the old Steady State models. Your bubble idea is in principle no different to Guth's inflation. But there need not be anything outside our universe or even any meaning to questions about events happening before the Big Bang. String theorists and their brane collisions would beg to differ eg. http://www.space.com/scienceastronomy/astronomy/bigbang_alternative_010413-3.html >> The problem with a better idea is that it is necessarily limited. >> >> There's a big army of people working out justifications and explanations >> and just-so stories that fit the current accepted theory. If you are one This is paranoid rubbish. Some of the best minds on the planet are working on ways to model the universe with mathematics and experimentalists are gradually confining their wilder flights of fancy. The challenge is always to find the experiment that breaks the mould. The mathematics of string theory might ultimately be shown to be correct, but at present the classical GR solutions predictions are as good as it gets. Astrophysics allows our understanding to be tested at energies that are simply not available in terrestrial laboratories. > --- > That's exactly the predicament Galileo found himself in when he rejected > the geocentric Ptolemaic system in favor of the heliocentric Copernican > system, the guilt of that heresy only being "pardoned" by the Church > after 360 years! > > So, it matters less that a battle is lost rather than the war. > --- You cannot reject something until you have something better to put in its place. And if you are going attempt to argue that Big Bang cosmology is wrong you have to understand what it is first. > Indeed, and it seems to me that Occam's razor favors a mass external to > our bubble causing galactic acceleration rather than the added epicycles > of dark matter and energy invented to bolster up the big bang. For every complex problem there is a simple wrong answer. You have found one. It is a well known result of inverse square laws that inside symmetric shells of matter you feel no net effect from them. The same applies to electromagnetism and gives us Faraday shielding. Dark matter incidentally was not invented to fix the Big Bang, but to explain the speed that stars move around galaxies. When I was in the field dark matter could easily have included anything non-luminous not a star and now a gas or plasma. This included old-biros, rocks, asteroids, chair legs and sticks of rhubarb. These days the much more sensitive observations constrain most of it to be something more exotic. Some cosmological dark mass may well be hiding in the neutrinos. > Not necessarily the known universe, just the matter within it > accelerated by a mass external to our bubble attracting matter within > our bubble according to an inverse square law. Forbidden by Gauss's theorem. Doesn't work. >> One possible explanation is that the universe is not accelerating in all >> directions but that for some reason light gets slowly red-shifted as it >> travels. So called tired light theories. Tested and found wanting. Ned Wrights cosmology FAQ deals with some of your misconceptions but you would be better off with a modern graduate text like Peacock if you have the necessary mathematics to read it and understand the arguments. http://www.astro.ucla.edu/~wright/cosmo_01.htm > That would require the photons to slow down for some reason, causing > their wavelengths to increase. Photons travel at the speed of light in a vacuum. They may lose a bit of energy climbing out of a gravitational potential well - see Mossbauer effect which can be easily demonstrated on Earth. eg http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/mossb.html But it isn't enough to explain quasars. > > However, once they traversed whatever medium was slowing them down > they'd speed up to 'c' again and the wavelength would decrease to what > it was before the slowdown. You have this exactly backwards. When entering a medium with a slower speed of propagation the continuity condition at the boundary requires that in the slower medium the wavelength is shorter. > --- > >> Or perhaps atoms used to emit light that was red-shifted compared >> to the light they emit now. > > --- > Only if they've slowed down, I think. Dirac considered the possibility that the fundamental constants of nature were variable on the cosmological timescale. No satisfactory evidence of this has ever been found. Neutral hydrogen appears to emit at 21cm everywhere we can detect it and the same for Lyman alpha which is visible at great distances. > > Consider: > > If one of the electrons of an atom at rest is excited to the point where > it jumps an orbital and then releases a photon when it jumps back, the > wavelength of that photon can only decrease if the atom moves away from > a reference at rest. > > So, it seems that if the light was once red shifted, compared to what it > is now, it can now only be less highly red shifted if the atom's speed > decreased relative to the reference at rest. > > But that's not what we see, which is that the more distant the galaxy > the more highly red-shifted the light from it is. And that latter observation is simply down to the expansion of the intervening space. You can get a long way with handwaving arguments, but if you want to understand modern cosmology you really need to get one of the introductory graduate texts. Otherwise you are simply arguing against strawmen of your own construction. > --- > >> I see no obvious way to test these ideas. > > --- > It can be done with atomic clocks and airplanes. Not a chance. The atomic clock tests on airplanes is done and is exactly consistent with the predictions of GR as are the GPS satellites which would not have worked if GR was wrong. >> How could anyone possibly tell whether something is a better idea, until >> it became the standard model that most physicists agree on? > > --- > Galileo did, Newton did, Einstein did... > > All the giants did. You have to show that the idea actually works and predicts answers that the prevailing theory cannot get correct. To do this you actually need to understand the current theories and supporting observations in some detail and not some tabloid journalists half baked interpretation. This might be better off in sci.astro, but unfortunately that group attracts every conceivable nutter and raving loon with a new theory of everything. Most of them type all in capitals too. There are a also few good guys there who might point you towards other references that would help you refine your ideas. Regards, Martin Brown
From: Martin Brown on 7 Jan 2010 11:32 John Fields wrote: > On Tue, 05 Jan 2010 09:52:32 +0000, Martin Brown > <|||newspam|||@nezumi.demon.co.uk> wrote: > >> Exponential inflation has made >> a very large universe, we can only hope to see a fraction of it, and to >> a very good approximation it looks similar in all directions. And >> amazingly smooth at the furthest extremes in the CMB wavelengths. > > --- > If we do live in a bubble universe such as I envision, then the > exponential inflation came about and continues to exist because of the > tugging on what matter lies within our bubble by what lies beyond it, on > the other side of the wall. > --- Gauss's theorem says you are wrong. >>> Looking at it from the point of view that matter is accelerating away >>> from us as its distance from us increases makes no sense in a big bang >>> universe since, after the initial acceleration, nothing would be driving >>> the mass and one would expect that matter would either recede at a >>> constant velocity if the universe was open, stop if the universe was >>> static, or accrete if the universe was closed. >> Not quite. Open universes expand forever and matter still has a finite >> velocity at infinity, and closed or bound ones it reaches zero and moves >> in again at some period - cyclic if you allow it to rebound. > > --- > How is that different from what I stated? They don't recede at constant velocity. Work is being done moving the masses away from each other against gravity and they slow down. In the limit the barely open universe just halts when it gets to infinity. >>> Such is not the case however, and for matter to accelerate as it gets >>> farther way from us requires that some force be attracting it. >> Or some force to be repelling it which is how the field equations >> represent dark energy (not a term I like). > > --- > Nor I. > > My feeling is that dark energy and dark matter were invented in order to > hold on to the proposition that the big bang really existed, rather than > to seriously consider other origin scenarios. Dark matter was invented a long time ago to explain the observed motion of stars in galaxies. There simply is not enough luminous mass in the stars and nebulae to allow the velocities seen in the outer spiral arms - something else is providing additional gravity. NB The earth counts as dark matter as do any asteroids, black holes and other non-luminous material. But that still isn't enough so there has to be something else heavy and not interacting electromagnetically that comes into play at galactic scales. Neutrinos may be a part but again still not enough. > > Time will tell, I suppose. Dark energy was originally invented to allow the Einstein field equations to model a Steady State universe. It fell out of favour when the Big Bang cosmologies defeated Steady State. Now it has become a possibility again that it is non-zero although small. The observed acceleration is a relatively small correction at very high Z. >> NB Cosmological expansion of space itself at large distances is not >> limited by the SR restriction of being less than c. This means there are >> or could be parts of our universe moving away so fast that they can >> never be reached even at the speed of light. > > --- > Which would also mean that our universe wasn't surrounded by uniform > shells of external matter, since we actually _do_ see galaxies flying > toward the wall, and going faster and faster as they get closer and > closer to the wall. But we see it symmetrical in all directions. Spherical symmetry and Gauss's law means you cannot feel the external shells of material inside. > --- > >> You cannot have uniform shells of external matter accelerating things >> towards them Gauss's Theorem prohibits that entirely. > > --- > Then, since we _do_ see acceleration, that must mean that the > gravitational attraction from what's behind the wall isn't uniform. But the observed acceleration is uniform in all the directions we can see. >>> As you say, there are, interestingly, blue shifts in our local group >>> which indicate that some of our members are being attracted to each >>> other. >> It is called gravity. > > --- > Please, try to be a little less condescending and keep from turning this > discussion into a flame war, OK? You need to think a lot more carefully about the various length scales involved. It is no surprise that local cluster galaxies are gravitationally bound and some are moving towards each other. >>> Even as that happens, though, we're _all_ accelerating toward the wall, >>> sort of like people walking toward each other on a train accelerating >>> toward a mountain. >> You seem to be using the word "wall" in a non-standard way. > > --- > Perhaps, but since I'm using it to describe the delineation between a > bubble universe and what lies beyond it, its meaning should be clear. It might be clear to you but if you are using a term already used in the literature with another meaning entirely it isn't a wise choice. http://en.wikipedia.org/wiki/Great_Wall_(astronomy) >> Observations >> of galaxy distributions have put some pretty tight constraints on what >> is possible. >> >> http://en.wikipedia.org/wiki/Galaxy_filament > > --- > Since all of those structures lie within the bubble, that has little to > do with my hypothesis since the wall I describe is used to indicate the > delineation between a bubble universe (of which the galaxies you cite > are members) and what lies beyond it. Whatever is out there is so far away that its gravitational influence has not yet had time to reach us. GR has certain game rules. Regards, Martin Brown
From: Bill Miller on 17 Jan 2010 14:47 "Jonah Thomas" <jethomas5(a)gmail.com> wrote in message news:20091229155326.79864524.jethomas5(a)gmail.com... > "Bill Miller" <billmillerkt4ye(a)worldnet.att.net> wrote: >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote >> > Paul Keinanen <keinanen(a)sci.fi> wrote: >> > > > I'd say there's pretty strong evidence that some oil has organic > sources. But that doesn't say it all does. If it turns out that oil > precursors are formed deeper and then percolate upward through the rock, > to sometimes get captured by oil domes where they gradually get > converted into polycyclic forms -- we might be able to collect more of > it in the precursor form, beyond just getting it from existing domes. > There are more exciting possibilities than I can keep track of, and I > have no idea to tell which handful of them will actually pay off. Now that the "flame wars" seem to have died out, I'd like to explore the above a bit. I've done a bit of looking for laboratory evidence that *any* oil has biotic precursors. The Fischer-Tropsch process used by Germany in WWII to produce Synthetic Gasoline from CO, Hydrogen and catalysts is well known. But the results are impossible to achieve *outside* of a laboratory, and the "ingredients" are not biotic compounds. Other than this, there seems to be a lot of theoretical rambling not too far removed from hand waving. I would be interested in links to actual experiments that started with biotic materials and ended up with any or all the compound(s) that are also found in petroleum. In contrast, there seems to be a fair amount of theoretical and lab activity in taking carbonates (limestone, marble etc.) and subjecting them to intense heat and pressure in the presence of water and Iron oxide (as a catalyst). The outcomes contain all of the compunds usually found in petroleum. Unfortunately, almost all this work is in Russian. Here is a US site that links to many of the Russian works and also to an impressive (to me) English language experiment re carbonates-to-oil. http://www.gasresources.net/ All the best, Bill Miller
From: Archimedes' Lever on 18 Jan 2010 19:50 On Mon, 18 Jan 2010 16:33:21 -0500, Spam(a)ControlQ.com wrote: >On Sun, 17 Jan 2010, Bill Miller wrote: >> I've done a bit of looking for laboratory evidence that *any* oil has >> biotic precursors. The Fischer-Tropsch process used by Germany in WWII to >> produce Synthetic Gasoline from CO, Hydrogen and catalysts is well known. >> But the results are impossible to achieve *outside* of a laboratory, and the >> "ingredients" are not biotic compounds. Other than this, there seems to be a >> lot of theoretical rambling not too far removed from hand waving. I would be >> interested in links to actual experiments that started with biotic materials >> and ended up with any or all the compound(s) that are also found in >> petroleum. > >I heard recently that German scientists had found a way to convert kitty >cats into diesel fuel. Does that count? That depends on what a kitty cat is.
From: Bruce McFarling on 18 Jan 2010 21:07
On Jan 17, 2:47 pm, "Bill Miller" <billmillerkt...(a)worldnet.att.net> wrote: > I've done a bit of looking for laboratory evidence that *any* oil has > biotic precursors. That would be quite on topic too, as long as that laboratory equipment or some of the data processing was programmed in Forth. |