Talk:Metric expansion of space

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Former good article Metric expansion of space was one of the Natural sciences good articles, but it has been removed from the list. There are suggestions below for improving the article to meet the good article criteria. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.
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Contention That Evidence of Expanding Universe has been Misinterpreted[edit]

Following some edits to make this a bit more concise and to overall improve the writing, I would add the below as a section to the main article:

Expanding universe, smechspanding schmuniverse. I'm sorry but I believe that the astrophysicists are wrong. They've concluded that the universe is expanding based on one observation, an observation that I would say they may have misinterpreted. And they've gone down the path of inventing a bizarre hypothesis to try explain the contradictions between their conclusion and accepted and proven physics - rather than going back and correcting their error.

Let me explain. A while back some scientists happened to notice that light from distant objects (stars and galaxies) in space was red-shifted. Upon closer observation they learned that the more distant the object the bigger the red shift. And this was the case no matter which direction you looked. Interesting...

Redshift of light is nothing new. Einstein developed theories that said redshift occurs in the light sourced from an object when that object is moving away from you. Information on redshift: http://en.wikipedia.org/wiki/Redshift . Other people have gone on to measure light from objects that are moving away from us at known speeds and have proven Einstein correct in this - light sourced from objects moving away is indeed red shifted, and redshift increases as the departing velocity increases.

But there is nothing that says that there could not be other phenomena that might cause redshift.

When the scientists found redshift assiociated with distant space objects they jumped to the conclusion that they were moving away from us - and from only this one piece of evidence they went on to conclude the universe is expanding. But then, there was an issue with this idea. In a uniformly expanding universe the relative velocity between two objects grows in proportion to the distance between the objects. Based on the observed "expansion rate" of our universe if two objects are > 4.5 gigaparsecs apart then the relative velocity between the objects will exceed the speed of light. Since it is well established that the speed of light cannot be exceeded, you either have to question the expanding universe hypothesis, or you have to invent some new concept that says you're really not exceeding the speed of light, something else is going on.

The concept invented was that the objects are not really moving apart from each other, rather the space between them is just expanding. http://en.wikipedia.org/wiki/Metric_expansion_of_space Whaaaat?!! And then, on top of this, the theorists added the qualifier that the expansion of space is happening only on cosmic scales - this would explain why we don't see any "expansion of space" when we do precise measurements on things like the distance between the moon and the earth. Other theories have been formulated, and more are being formulated as we speak, to explain more of this picture of an expanding universe and to try to reconcile it with known and proven physics.

In my opinion the astrophysics community is long overdue take a big step back and re-consider the original, and in my belief mistaken, notion that the redshift of light from distant objects is proof that the universe is expanding.

So what alternative interpretation of the observed redshift could there be? Consider this: maybe light ages as it propagates across the universe. And as it ages, it loses energy - hence the red shift. Because of the fixed speed of light, light that we observe originating from more distant objects is of course older. So this ageing hypothesis explains the observed increased red shift with distance - without having to conclude that the universe is expanding, and without contradicting known and proven physics.

How would a person go about proving that light becomes red shifted as it ages? Well, how about shining some light at the moon and then precisely measuring the wavelength of the reflected light that comes back? — Preceding unsigned comment added by Keithsinterweb (talkcontribs) 18:20, 8 December 2012 (UTC)

That idea is called Tired Light, and it has already been considered, and rejected for lack of any supporting evidence, by the scientific community. Perhaps you should read about the observational evidence for the concordance cosmology, which is much more than just the observation that redshift and distance are correlated. Contrary to your assertion, the observed expansion of space does not contradict "known and proven physics", whereas any viable tired light hypothesis most certainly would. - Parejkoj (talk) 15:30, 9 December 2012 (UTC)

Red shift[edit]

All units in space times are imperfect. This means that they change, ether continuously or quantitatively, depending on the unit of measurement ‘now’ of the observer. The change is the difference in the unit observed in two ‘now’ of the observer. The units of change are additive and the sum manifests itself as an interval of time but also as the big difference between the beginning ‘0’ and the end ‘1’ in the transformation, or an evolution, contained within the space (0<1). Motivation for change originates in the immaterial space time. It causes, for example, quantitative change (explosion) of the neutron after 15 minutes. Applied to a photon the change is the ‘red shift’ in the units of electromagnetism. KK (83.22.28.60 (talk) 13:03, 14 January 2013 (UTC))

lol, WP:NOR.1812ahill (talk) 17:14, 28 October 2013 (UTC)

I have a problem with "gravitationally bound/unbound"[edit]

I suppose that basically Newton is still applicable here. Gravitation is inversely proportional to distance squared, a decent continuous function - no bumps. Thus, between two masses, depending on their distance yes but nevertheless, there is always gravitational attraction, near and far, all the way towards infinity. So in my opinion, two bodies are always gravitationally bound, regardless of distance. The link to explain "gravitationally unbound" points to an article on archery (?), it does in no way explain the difference between "bound" and "unbound". Yet I get the impression that in case of "bound" there are no traces of any Hubble expansion (the distance between Earth and Moon is indeed increasing, but only due to tide) and in case of "unbound" it is 100% Hubble. There seems to be no 50% in between. I think that this discontinuity should be explained. Especially if it disqualifies Newton's equation (Wouldn't that be a sensation!  ;-) So what I'm asking for is a decent explanation of "gravitationally bound/unbound". The current one is not. / Ola — Preceding unsigned comment added by 212.247.27.221 (talk) 15:50, 20 June 2013 (UTC)

virial theorem would be a more natural redirect. Thanks. jps (talk) 03:11, 20 January 2014 (UTC)

How the current explanation for the Cosmological Red-Shift, based on ‘metric-expansion-of-space’, can not be correct[edit]

In a paper recently published in Adv. Studies Theor. Phys., Vol. 7, 2013, no. 20, 971 - 976 http://dx.doi.org/10.12988/astp.2013.39102; titled: "Wave-Theoretical Insight into the Relativistic Length-Contraction and Time-Dilation of Super-Nova Light-Curves" by Hasmukh K. Tank, a sub-section reads as follows: "2. How the current explanation for the Cosmological Red-Shift, based on ‘metric-expansion-of-space’, can not be correct: Currently, the cosmological red-shift is understood in terms of ‘metric-expansion-of-space’. It is believed that after the big-bang the space-time started expanding; so the distances between galaxies are increasing, even at the rates faster than the speed of light, near the edge of the universe. So, the wavelengths of extra-galactic-photons get stretched with the expansion-of-space, resulting in the observed ‘cosmological-redshift’. Now, I present here an argument that this explanation can not be correct, as follows. Accepting that the space between the galaxies is expanding; but the space within the galaxies is not expanding, because galaxies are gravitationally bound structures. So, there has to be a smooth transition, from the expanding-space out-side the galaxies, to the non-expanding-space within the galaxy. Now, when the extra-galactic-photons, after their long-long extra-galactic-journey, with their wavelength stretched due to ‘expansion-of-space’, enters the ‘transition-region’ from expanded-space to ‘non-expanded-space’, then their wavelength should start shrinking-back, like it shrinks while entering stronger and stronger gravitational-field; and when they enter the non-expanded-space of our milky-way-galaxy, their wavelength should shrink-back to original wavelength! Isn’t it? Therefore, the current explanation for the ‘cosmological-red shift’, which is based on ‘metric-expansion-of-space’, can not be correct. Every scientist has accepted my argument, that: “there has to be a smooth transition, from the expanding-space out-side the galaxies, to the non-expanding-space within the galaxy” when I attempted to explain galaxies’ rotation-curves based on this smooth-transition of expansion-of-space. This has encouraged me to think of ‘shrinking-back’ of stretched-wavelength of extra-galactic-photons while entering the non-expanding-space of our milky-way-galaxy." 210.56.145.241 (talk) 16:39, 22 October 2013 (UTC)210.56.145.241 (talk) 16:43, 22 October 2013 (UTC) Regarding The Accelerated-Expansion of Space, this paper has this to say " This author has recently proposed four alternative-interpretations for the ‘cosmological-red-shift’ [3-5]. According to these new interpretations the red-shift depends only on distance traveled by the extra-galactic-photons, not on the relative-velocity of the source-of-light and observer. Therefore, as the photons travel a unit-distance, say one light-year, then there is certain amount of red-shift; say the frequency of photon which was f0, reduces to f = f0 / 1.1. Then for the next unit-distance f becomes the new input frequency which gets red-shifted to f / 1.1 = f0 / ( 1.1)^2. Then for the third unit-distance, new value of f = f0 / (1.1)^3. Thus the red-shift-distance-curve becomes automatically non-linear, as observed, without invoking any ‘dark-energy’. Perlmutter and Riess based their interpretation of non-linearity of red-shift-distance-curve, on the current, ‘metric-expansion- of-space-based-explanation' for the cosmological-red-shift, so they needed invocation of ‘dark-energy’[6,7], whereas here in section-2, we found that ‘metricexpansion-of-space’ can not explain the observation of the ‘cosmological-red-shift’. Thus there has been a need for considering alternative ways to understand ‘relativistic-length-contraction’, ‘time-dilation’ and the observations of ‘cosmological-red-shift’. 49.213.62.187 (talk) 08:11, 23 October 2013 (UTC)

Time-dilation of super-nova light curves can also be alternatively-explained

In a paper recently published in Adv. Studies Theor. Phys., Vol. 7, 2013, no. 20, 971 - 976 http://dx.doi.org/10.12988/astp.2013.39102; titled: "Wave-Theoretical Insight into the Relativistic Length-Contraction and Time-Dilation of Super-Nova Light-Curves" by Hasmukh K. Tank, time-dilation of super-nova light-curves is alternatively-explained as follows: 3.2 Explanation for the Time-dilation of Super-Nova Light-Curves: Super-nova-light-curves, described by Giacobbe, [2], can be viewed as a ‘gate-function’ in the ‘time-domain’; and it can be Fourier-transformed into frequency-domain; and it is this wide band of waves which travels in space and reaches us after millions of years. During its travel, when this wide-band of waves, being electromagnetic waves, gets red-shifted due to any mechanism then its band-width shrinks in the frequency-domain; so when it is transformed back into time-domain we find that the duration of the curve has got increased. Thus, time-dilation of supernova-light-curves is not an independent observation from the observations of the‘cosmological-red-shift’ due to any mechanism. Thus this paper reaches two interesting conclusions regarding the two predictions of General Relativity: 1. Metric-expansion-of-space can not explain the observation of the 'cosmological-red-shift' because if the wavelength can streatch due to expansion-of-space, then it should have got shrunk while entering the 'transition-region' from 'expanding-space-between-the- galaxies' to 'non-expanding-space-within-our-milky-way-galaxy'; and 2. 'Time-dilation-of-super-nova-light-curves' can be explained by any alternative-explanation for the 'cosmological-red-shift', i.e. observations of time-dilation-of-super-nova-light-cureve are not the exclusive tests of General Theory of Relativity.123.201.19.219 (talk) 16:31, 25 October 2013 (UTC)

I may be wrong, but I'm surprised that a journal as prestigious as "Advanced Studies in Theoretical Physics" doesn't have an entry in that font of all knowledge, namely Wikipedia, particularly as it has now reached the grand old age of 7. I'm also surprised that its publisher (Hikari Ltd.) is also not worthy enough to have found its way into Wikipedia, unless of course it is this Hikari company (ROFL).1812ahill (talk) 17:54, 28 October 2013 (UTC)

Hikari company mentioned in the above post is different from the publishers of the journal Advanced Studies in Theoretical Physics. Company mentioned in the above post is Japan-based food company; whreas Hikari Ltd. is based in Bulgaria, publishing various scientific journals, and books, like Springer publishers. Their web-site-address is www.m-hikari.com. 49.213.62.195 (talk) 15:08, 30 October 2013 (UTC)

Independent sources will be required before such "alternatives" can be addressed at this article. jps (talk) 03:16, 20 January 2014 (UTC)

Restored some text, moved some other text into a new section, tried to fix some of the heaviest non-sense[edit]

This article is complete chaos. The "sources" given are in most cases not real "sources" of research, but links to some sort of apparent authority upon some part of research somehow related to a subject related to the title of this article.

The article is heavily biased and does NOT express various views upon the exact nature of this expansion, even if we would accept without question that the universe is indeed expanding. Even those who believe so are in great disagreement about how to incorporate such a fact into a general theory, of which there are as many different versions as may be expected in a subject of this scale and complexity.

Large parts of the article is written in vernacular, "popular" or "American" English. This renders the article severely imprecise.

The question remains whether wikipedia should unanimously proclaim something absolute "truth" or not! If not, it should be clear that we are dealing with theories, and that several conflicting theories exist. Most important of all, it should be clear to all readers that the man after whom the "Hubble constant" and "Hubble's law" were named, did not himself from at least 1936 to his death in 1953 support an expanding universe interpretation. — Preceding unsigned comment added by 212.95.7.13 (talk) 07:51, 3 December 2013 (UTC)

This strange interpretation that Hubble didn't support the expanding universe is making a lot of hay out of two papers on the interpretation of his eponymous law. The quotes are apt and interesting and the full story is told by Norriss Hetherington in his various books, but, suffice to say, Owen Gingerich has the correct answer. Hubble wasn't one to believe or disbelieve. He simply put forward observations and made conclusions as best he could. That he messed up in getting too large a Hubble Constant is an interesting part of the story, but it is by no means the entire story. jps (talk) 03:15, 20 January 2014 (UTC)

Notes[edit]

Definition of "Stationary" must be provided[edit]

"if it were possible to place a tape measure between even stationary objects, one would observe the scale of the tape measure changing to show more distance between them." -- sorry, then the objects are not stationary. Obviously, an unusual definition of "stationary" is being used, but this has to be defined first. Otherwise I could claim that an airplane flying away at 600km/h is actually stationary relative to me and it's just the space between us two which is expanding. 46.126.115.103 (talk) 20:04, 14 December 2013 (UTC)

False claim: tracking a straight line doesn't measure distance[edit]

"this distance can be measured by tracking a straight line between two points" - that's an obvious nonsense. Try it. Take two nails, hammer them into a board at random location and take a piece of string. Connect the nails with a taught piece of the string. Now "track the straight line" (like with your finger). Do you know the distance now? Of course not! All you know is just the points through which the straight line goes! You need more than just "tracking a straight line between two points" - a kind of tape measure which spits out something like "14.3" or "8.87" and on top of that you even have to know what units these numbers are calibrated in. This sentence needs to be replaced with a different sentence which is not patently false. 46.126.115.103 (talk) 20:12, 14 December 2013 (UTC)

Thanks for the notes[edit]

Thanks for the notes, 46.126.115.103. I have tried to address all of your concerns. jps (talk) 03:15, 20 January 2014 (UTC)

A New Contributor to the Non-Linearity of Red-Shift-Distance-Curve Observed by Perlmutter and Riess: Namely the ‘additional-Red-Shift’ Caused Due to the ‘rate-of-Change-of-Brightness-with-Distance’[edit]

In a pre-print titled: "A New Contributor to the Non-Linearity of Red-Shift-Distance-Curve Observed by Perlmutter and Riess: Namely the ‘additional-Red-Shift’ Caused Due to the ‘rate-of-Change-of-Brightness-with-Distance’" is posted at 'viXra:1402.0058 [pdf] by Hasmukh K. Tank; whose abstract reads as, which may be found interesting: "According to the inverse square law, the brightness of every source-of-light reduces with distance. And the rate of reduction of brightness at various radial distances keeps on reducing with distance. From our experience of ‘amplitude-modulation’, we know that change of amplitude of a stable, single-frequency-source produces a wide spectrum, depending upon the ‘rate-of-change-of-amplitude’; so the varying ‘rate-of-reduction-of-brightness’ with distance of the galaxies and super-novae, must have contributed ‘additional-red-shift’; in addition to the well known Doppler-shift. It is proposed here, that: since this ‘additional-contribution-to-the-red-shift’ is non-linear, the ‘red-shift-distance-curve’ observed by Perlmutter and Riess shows non-linearity; but this ‘additional-contribution-to-the-red-shift’ does not mean ‘additional-recession-of-galaxies’ and ‘accelerated-expansion-of-the-universe’ Bold text" 180.87.227.170 (talk) 10:25, 12 February 2014 (UTC)

About Effects of expansion on small scales

I have read this section while searching for the answer to a question I have, but I was not able to find this answer… because – IMHO – this section fails to make clear the distinction between expansion of space on one hand, and recession of objects on the other.

I know that the neighbor galaxy Andromeda navigates towards our galaxy at about 300 km/s, despite the fact that, according to the Hubble's law, the space should be expanding between both objects at about 50 km/s.

I am not fluent in cosmology, I am just an amateur in astronomy who wants to know:

- if the expansion of space is acting everywhere, at any scale…

- or if the expansion of space is not acting at small scale.

Saying this differently:

- Is the Effects of expansion on small scales just a signal-to-noise issue? Is space always expanding between two objects, whatever be their mutual distance? Is the relative velocity between two objects always the superposition of the objects speeds relative to their local space and the expansion of the space between them, at any scale… making that close objects may show no mutual recession?

- or is there truly no space expansion between close objects?

Sorry if my English seems strange, I usually speak French…

Thanks in advance,

Pehachem (talk) 16:59, 13 June 2014 (UTC)