Talk:Hubble's law/Archive 2

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Acceleration reference suggestion

Recent high red shift distance determinations show a departure from Hubble's law that has been interpreted as indicating an accelerated cosmic expansion.<ref| S. Perlmutter, " Supernovae, Dark Energy, and the Accelerating Universe", Physics Today, April 2003, pp 53-60 [supernova.lbl.gov/PhysicsTodayArticle.pdf] |/ref> (HCPotter (talk) 09:39, 1 January 2012 (UTC))

Photon expansion

Although the cosmic red shift is interpreted as a Doppler effect associated with remote light source recession relative to a local observer, actual spatial separation increase has not been verified. For photons with volume proportional to wavelength cubed, cosmic red shift is associated with photon expansion during the journey to the present from deep time and photons could be likened to bubbles rising in an effervescent liquid.Effervescence Such expansion could be mistaken for a Doppler red shift. If combined with the standard photon electromagnetic field <ref| H. C. Potter, "Metanalysis validates comprehensive two part photon", Apeiron 18:3(2011)254-69. [1] |/ref>, added per photon dimming would reduce determined stellar distances, decelerating cosmic expansion.(HCPotter (talk) 09:34, 15 January 2012 (UTC))

File:Edwin Hubble.jpg Nominated for Deletion

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Merger from Dimensionless Hubble parameter

I went ahead and merged the content from Dimensionless Hubble parameter into the article (with minimal alteration to italicise h and H₀). I probably didn't follow the exact merging procedure, but it seemed to me like a reasonably clear-cut case, since even Hubble's constant itself doesn't have an article. I put the content under Interpretation, as it seemed too long to put in the intro. Hopefully, that's a good place for it. -Anagogist (talk) 22:55, 29 February 2012 (UTC)

This is really not 'dimensionless', since it really amounts to the measure of $H_{0}$ in parsec.seconds/dm. It's like saying that measures in millimetres (on engineering diagrams, numbers without measures are m/m measures) are also dimensionless numbers.

The hubble constant is $H_{0}$ = $h$ dm/pc.s. The hubble unit is then "dm / pc.s " or (100 km/s)/(MPc). Wendy.krieger (talk) 07:24, 5 June 2012 (UTC)

Cumulative Phase-Alteration of Galactic-Light Passing Through Cosmic-Microwave-Background: Possible New Mechanism for the Cosmological-Redshift

Possible New Mechanism for the Cosmological-Redshift: In the volume-III of Progress in Physics, July 2012, possible new mechanism for the cosmological-redshift has been proposed by Hasmukh K. Tank. This mechanism can account for a large percentage of the redshift; reducing the requirement of 'dark-energy', may be, to the observable 5% mass of baryonic-matter. [Ref. Tank H. K. "Cumulative-Phase-Alteration of Galactic-Light Passing Through the Cosmic-Microwave-Background: A New Mechanism for Some Observed Spectral-Shifts" Progress in Physics, Vol 3, July 2012, pp 39-42] — Preceding unsigned comment added by 122.102.126.92 (talk) 17:26, 8 August 2012 (UTC)

Perhaps in a few years, when there are wp:secondary sources for this. - DVdm (talk) 18:06, 8 August 2012 (UTC)

Spherically-Expanding-Wave-Front of Light Viewed as Gated-Plane-Wave, to Understand the Cosmological Red-Shift

"A spherically-expanding-wave can be viewed as a plane-wave passing through a gate, of slit-width Δ d = 2 c t . As the wave-front progresses, the equivalent-width of the gate-function goes on increasing. This is equivalent to multiplying in space-domain, a sinusoidal-wave with a gate-function of width Δ d = 2 c t ; and when we Fourier-transform it, we get a spectrum which goes on shifting toward lower-wave-number-side, as the wave-front expands. This attempt leads to an insight that it is the wave-front which expands, and not necessarily the ‘space’! And the ‘cosmological-red-shift’ may be simply due to this ‘propagation-property’ of light." From the abstract of a manuscript by: Hasmukh K. Tank, who had previously proposed a view that a spherically-expanding-electromagnetic-wave-of-light can be veiwed as a wave within a wave-guide-cavity, which goes on increasing with the wave-front of the spherically-expanding-wave. 121.246.200.77 (talk) 10:48, 4 March 2013 (UTC)

Not Lemaître's Law

If you search Google Lemaître's law, you won't find any citations except on Wikipedia of references to that name. Yes, there is evidence recently that Lemaître may have actually first derived the law, but that doesn't mean the law's name suddenly changes. As far as I can tell, there is no real effort in the scientific community to change the name; as a result, the name is as it stands right now: Hubble's law. I removed the "or Lemaître's law" portion a while ago with a detailed rationale in the comment, but that change appears to have been reverted by someone who failed to provide any reason for doing so. As Wikipedia is not the place to start such a movement to change the name of a scientific law, I will (again) remove that portion. ALK (Talk) 04:19, 20 December 2012 (UTC)

I agree. The bibliographic credit for discovery has been discussed in the recent 2-3 years, as is indicated by the references in this article, and Hubble's role is less god-like than it was earlier. But there's little movement to change the name "Hubble's Law" to "Lemaitre's Law" (or the Slipher-Wirtz-...-Lemaitre-Hubble Law). In the absence of a reliable source, I'm reverting to your (ALK)'s correction. Boud (talk) 22:21, 30 October 2013 (UTC)

Doppler shift → relative velocity

April 3, 2013 the very first sentence in this article states: "Hubble's law is the name for the astronomical observation in physical cosmology that: (1) all objects observed in deep space (intergalactic space) are found to have a Doppler shift observable relative velocity to Earth, and to each other...". I challenge the assertion that we have OBSERVED their Doppler shift from anyplace other than Earth. It is a simple statement of fact, which I am confident is just plain wrong. It is disappointing that the authors can not distinguish between measurements and theory. Most high school students can, when taught the difference.173.189.76.217 (talk) 12:53, 3 April 2013 (UTC)

• You might have mistaken what is meant by relative velocity. From earth we can observe two light sources in the same area of the sky that have different red shifts compared to each other (an observable "fact"). We infer that the source with the greater red shift is moving away faster (and thus is farther away) (according to theory). 75.208.245.67 (talk) 06:54, 2 July 2013 (UTC)

In Galilean relativity or Minkowski spacetime, velocity in general is a vector, so talking about "to each other" is ambiguous to the reader. In reality, in general relativity velocity is a local property of a worldline - you can't arbitrarily shift it somewhere else without saying (at least implicitly) in what way you shift a four-vector from one spacetime location to another. For the lead of this article, IMHO stating that the speeds are approximately proportional to the distance is reasonable as an approximate explanation. Boud (talk) 02:37, 31 October 2013 (UTC)

proportionality regime

From a hidden comment in the article: I though this was applicable to anywhere from a few 10 Mpc to the edge of the observable universe.

I've added refs to the main SNe type Ia papers - Fig 1 of Perlmutter et al and Fig 4 of Riess et al have log-log redshift-luminosity diagrams. Divide the vertical axis (m-M) by 5 to get a log10 axis scale in comoving radial distance (to match the log10 z scale), provided that we ignore the extra (1+z)^2 effect in the luminostiy distance. On a log-log scale, the non-linearity is not so obvious, but it's easy to see that at z about 1 or so the dependence on the curvature parameters (Omega_m, Omega_Lambda) is significant.

Depending on what is interpreted as "approximately", going to z=0.3 or z=1 could be considered approximately linear. But then there's the problem of when to inform the reader that z is not proportional to the Minkowski spacetime Doppler interpretation of a cosmological redshift as a speed (which is a valid interpretation after parallel transporting the velocity four-vector along a null geodesic from the emitter to the observer). Leaving these aspects until later/deeper articles is possible by limiting the "approximately valid" scale to a few 100 Mpc, maybe 1 Gpc.

The image at File:CosmoDistanceMeasures_z_to_1e4.png also makes it clear that above a redshift of about 0.1, the various notions of distance that can be useful in cosmology start diverging. Boud (talk) 02:54, 31 October 2013 (UTC)

There's also a linear distance vs log10 redshift diagram at File:Distance compared to z.png - you can invert this mentally by imagining a (positive) exponential that fits the left part of the main curve - it's clear that this has to fail somewhere no higher than z about 1. Or you could download the cosmdist GPL'd commandline tool (or use its C or fortran library) and make an actual calculation... Boud (talk) 03:13, 31 October 2013 (UTC)

And finally, even easier: a linear-linear plot: File:CosmoDistanceMeasures z to onehalf.png. Divergence of various distance measures is clear starting from about z=0.1, depending on which sort of distance you choose. This gives zc approx 30000km/s, divide by H₀ approx 70km/s/Mpc, and we get 400 Mpc. So "a few 100 Mpc" is reasonable. Boud (talk) 03:30, 31 October 2013 (UTC)

Santilli's IsoRedShift Interpretation

Comments by blocked WP:SPA
The following discussion has been closed. Please do not modify it.
In accordance with Wikipedia rules, I took the liberty of adding a tentative section in the main article because Santilli's IsoRedShift interpretation of the cosmological redshift without expansion of the universe has been considerably discussed in the new media (see, e.g., listings at www(dot)santilli-foundation.org(/)Conf-2013-No-Univ-Exp(dot)php) and, quite honestly, I felt embarrassed by the silence at Wikipedia in the field. Hence. the hope of this intervention is that of promoting "scientific" comments, if at all possible, without the usual dubbing and the like, since we are dealing with apparent experimental verifications published in various refereed journals by a number of authors we simply cannot dismiss with personal views, thus requiring a serious scientific process, preferably based on counter-experiments. Regards to all Aabrucadubraa — Preceding unsigned comment added by Aabrucadubraa (talk • contribs) 20:28, 12 December 2013 (UTC) The rapid removal from the article of measurements published in refereed journals by independent scientists under the "fringe" dubbing without any technical argument whatsoever is highly disqualifying and abusive for Wikipedia. It makes me wonder what's happening to Beautiful America. Aabrucadubraa — Preceding unsigned comment added by Aabrucadubraa (talk • contribs) 20:54, 12 December 2013 (UTC) Following a wave of comments, again due to the treatment of the topics by over 500 newspapers, TV and radio shows listed in www(dot)santilli-foundation.org(/)Conf-2013-No-Univ-Exp(dot)php without a quotation as yet in Wikipedia, I request permission to re-upload the section on "Santilli's invariant derivation of Hubble's law z = H_oD" in a reduced text format, but maintaining the important refereed publications, particularly from independent scientists, and then initiate a "scientific" debate in these Talks, i.e., one without self-damaging dubbing. Aabrucadubraa — Preceding unsigned comment added by Aabrucadubraa (talk • contribs) 19:25, 13 December 2013 (UTC) Santilli's stuff is utter nonsense and pseudoscience and completely unfit for inclusion in Wikipedia, except on his own article, and then again, only if very clearly labelled as pseudoscience. See WP:FRINGE and WP:PROFRINGE for further details. Headbomb {talk / contribs / physics / books} 19:33, 13 December 2013 (UTC) How can you sit in judgment of a lifetime of Santilli's research, you being expectedly unemployed (being an article spotter.....) and scientifically uneducated because you do not know is that Santilli is providing mathematical, theoretical and experimental support of Hubble's historical rejection of the expansion of the universe because the implied acceleration is radial in all directions from Earth, thus implying a necessary return to the Middle Ages with Earth at the center of the universe. Your stand proves you are a "fringe" supporter of such nonphysical cosmological politics and confirms the conspiracy at Wikipedia denounced elsewhere and reproduced below. Also, you claim to be a supporter of Karl Popper. but then you did not read the Foreword of his last book in which he describes Santilli as the only scientist bringing science back to reality. Aabrucadubraa

Denunciation of an organized conspiracy at Wikipedia

More comments by blocked WP:SPA
The following discussion has been closed. Please do not modify it.
Dear Arthur Rubin, Steven Weinberg, Sheldon Glashow, Samuel Thing. Gabbriele Veneziano and other known physics administrators of Wikipedia, I have removed the "fringe" dubbing in the heading of the Santilli's article on the following grounds you should consider seriously: 1) The "fringe" dubbing is in violation of the basic rule of Wikipedia to provide factual information without advance judgments that must be left to the visitors; 2) The "fringe" dubbing is in violation of the second rule of Wikipedia to avoid discrimination. In fact, the dubbing is used for Santilli's theories but not for other theories supported by the administrators such as the conjectures of big bang, dark matter, expansion of space itself, and the like; 3) The "fringe" dubbing violates the third Wikipedia rule of avoiding repetitions. The article is full of statement to the effect that Santilli's theories are not accepted by the physics community at large. These statements should stay because true. However, the "fringe" dubbing in the top of all these repetitions shows a malignant intent whose implications should be pondered by the administrators; 4) The "fringe" dubbing was appropriate indeed fifteen years ago, but now Santilli's main theories (Magnecules, MagneHydrogen, IsoRedShift, IsoBlueShift, isodual theories, nuclear fusions without radiations, etc.) have been experimentally verified by independent scholars in refereed publications, thus causing evident credibility problems that Wikipedia administrators should appraise. Additionally, Santilli's theories have produced technologies currently developed by U. S. publicly traded companies (magnegas(dot)com, thunder-fusion(dot)com, and others and their foreign associates) following millions of dollars of investments both in USA and abroad whose dubbing as "fringe" is clearly self-damaging; 5) The last event that triggered this intervention (in the hope of preventing a predictable reaction by Scientific Ethics because damaging to all) was the immediate removal without any due process by the administrator of the article on Hubble's Law two days ago of my uploading of independent refereed publications on Santilli's invariant derivation of Hubble's law on grounds of being "fringe." This provides documentation on the existence at Wikipedia of an organized conspiracy by the Wikipedia administrators for their personal political agenda against due scientific process on Santilli's theories and against their industrial development of munch needed new technologies, including nuclear fusions without harmful radiations. Wikipedia administrators should ponder whether their documented decades of opposition to Santilli's studies is worth maintaining in this internet era where the control of science is impossible. Respectfully yours, Aabrucadubraa — Preceding unsigned comment added by Aabrucadubraa (talk • contribs) 14:44, 14 December 2013 (UTC) This article, like any other, will conform to Wikipedia policy. Accordingly, it will not be used to promote the fringe concepts of Ruggero Santilli. And cut out the batshit-crazy bollocks about 'conspiracies', 'ethics' and 'political agendas'. Santilli's ideas are rejected by the scientific mainstream on scientific grounds alone, and represented as such by Wikipedia accordingly. AndyTheGrump (talk) 15:29, 14 December 2013 (UTC) Aabrucadubraa, nothing originatng from the source http://www.santilli-foundation.org would qualify as a reliable source—see wp:reliable sources— for this edit. Wikipedia needs solid secondary sources—see wp:secondary sources—to establish contributions' dueness—see wp:DUE and wp:FRINGE. Taking on board that content will probably take some time and a significant number of secondary sources in main-stream scientific publications. What you call an "organized conspiracy" is nothing more than Wikipedia's baked-in policy. DVdm (talk) 15:33, 14 December 2013 (UTC) I don't think anything we say will make a difference. He doesn't even know what an Administrator is. Conspiracy theorists are usually impossible to budge. — Preceding unsigned comment added by Dougweller (talk • contribs) 19:13, 14 December 2013 (UTC) Doughweller, you are an example that it is impossible to defeat an ignorant man in argument as Wlliam McAdoo said. Have a life and go back to school — Preceding unsigned comment added by 100.44.112.221 (talk) 20:42, 14 December 2013 (UTC) Here is a source to address some of those concerns: http://www.santilli-foundation.org/Confirm-No-Exp.php Recently published, comprehensive and independent experimental measurements conducted in the U.S.A and in Europe [15] have confirmed Santilli IsoRedShift (IRS) of Sunlight at Sunset and Sunrise discovered by R. M. Santilli (Curriculum) in mathematical, theoretical and experimental publications [7-14] initiated back in 1978 when he was at Harvard University under DOE support. [....] [7] R. M. Santilli. Foundation of Theoretical Mechanics, Volume I (1978) [7a], and Volume II (1982) [7b], Springer-Verlag, Heidelberg, Germany, http://www.santilli-foundation.org/docs/Santilli-209.pdf http://www.santilli-foundation.org/docs/santilli-69.pdf [8] R. M. Santilli, "Lie-isotopic Lifting of Special Relativity for Extended Deformable Particles," Lettere Nuovo Cimento 37, 545 (1983), http://www.santilli-foundation.org/docs/Santilli-50.pdf [9] R. M. Santilli, Isotopic Generalizations of Galilei and Einstein Relativities, Vols. I [9a] and II [9b] (1991), International Academic Press, http://www.santilli-foundation.org/docs/Santilli-01.pdf http://www.santilli-foundation.org/docs/Santilli-61.pdf [10] H. Arp. {\it Quasars Redshift and Controversies.} Interstellar Media, Berkeley (1987). [11] R. M. Santilli, "Experimental Verifications of IsoRedShift with Possible Absence of Universe Expansion, Big Bang, Dark Matter, and Dark Energy," The Open Astronomy Journal 3, 124 (2010), http://www.santilli-foundation.org/docs/Santilli-isoredshift.pdf [12] R. M. Santilli, "Experimental Verification of IsoRedShift and its Cosmological Implications," AIP Proceedings Vol. 1281, pp. 882-885 (2010) http://www.santilli-foundation.org/docs/Isoredshift-Letter.pdf [13] G. West and G. Amato, "Experimental Confoirmation of Santilli's IsoRedShift and IsoBlueShift," Journal of Computational Methods in Sciences and Engineering, 12, 169 (2012), http://www.santilli-foundation.org/docs/Confirmation-IRS-IBS.pdf [14] R. M. Santilli, G. West and G. Amato. "Experimental Confirmation of the IsoRedShift at Sun at Sunset and Sunrise with Consequential Absence of Universe Expansion and Related Conjectures, " Journal of Computational Methods in Sciences and Engineering, 12, 165 (2012). http://www.santilli-foundation.org/docs/Confirmation-sun-IRS.pdf siNkarma86—Expert Sectioneer of Wikipedia 86 = 19+9+14 + karma = 19+9+14 + talk 20:02, 14 December 2013 (UTC) Regarding the fusion claims, here is a paper (http://www.santilli-foundation.org/docs/ICNF-Conf-2013.pdf). It cites the following references: REFERENCES [1] Santilli, R.M. Foundations of Hadronic Chemistry, with Applications to New Clean Energies and Fuels, Kluwer Academic Publishers: The Netherlands, 2001. [2] Day, D. Report on GC-TCD analysis and density measurements of Santilli Magne-hydrogen; Laboratory Report; 2011. http://www.santilli-foundation.org/docs/Eprida-MH-Certification-10-11.pdf [3] Yang, Y.; Kadeisvili, J.V.; Marton, S. Experimental Confirmations of Santilli’s MagneHydrogen: Int. J. Hydrogen Energ., 2013, 38, 5002. [4] Yang, Y.; Kadeisvili, J.V.; Marton, S. Additional Experimental Confirmations of the New Chemical Species of Santilli Magnecules. Open Phys. Chem., 2013, 5, 1-16. [5] Santilli, R.M. Elements of Hadronic Mechanics, Volumes I and II. 1st ed.; Ukraine Academy of Sciences; Ukraine, 1994-1995. [6] Santilli, R.M. Apparent consistency of Rutherford’s hypothesis on the neutron as a compressed hydrogen atom: Hadronic J., 1990, 13, 513, http://www.santilli-foundation.org/docs/Santilli-21.pdf [7] Santilli, R.M. Recent Theatrical Experimental Evidence on the Apparent Synthesis of the Neutron from Protons and Electrons. Chinese J. Sys, Eng. Electron., 1995, 6(4), 177. [8] Borghi, C.; Giori C.C.; Dallolio, A. CENUFPE Communication, 1969, Number 8 and (Russian) Phys. Atomic Nuclei 1993, 56, 205. [9] Santilli, R.M. Apparent confirmation of Don Borghi’s experiment toward the synthesis of neutron from protons and electrons. Hadronic J., 1997, 30, 709. [10] Kadeisvili, J.V. The Rutherford-Santilli Neutron. Hadronic J., 2008, 31, 1. [11] Santilli, R.M. The novel Intermediate Controlled Nuclear fusions, a repor for its industrial realization. Hadronic J., 2008, 31, 15. [12] Santilli, R.M. Experimental Confirmation of Nitrogen Synthesis from deuterium and Carbon without harmful radiations. New Adv. Phys., 2011, 4, 29. [13] Brenna, R.; Kuliczkowski, T.; Ying, L. Verification of Santilli intermediate Controlled Nuclear Fusions without harmful radiations and the production of magnecular clusters. New Adv. Phys., 2011, 5, 9. [14] Santilli, R.M. Additional Confirmation of the “Intermediate Controlled Nuclear Fusions” without harmful radiation or waste: Proceedings of the Third International Conference on the Lie-Admissible Treatment of Irreversible Processes, C. Corda, Editor, Kathmandu University: Kathmandu, Nepal, 2011, pp. 163-177. [15] Rossiter, D. ONEIDA gas chromatographic report. http://www.santilli-foundation.org/docs/Oneida-analyses.zip [16] Lynch, C.; Yang, Y. Collected recorded data on the Nitrogen synthesis. http://www.santilli-foundation.org/docs/Collected-recordeddata.zip [17] Panton, R.L. Incompressible Flow, 2nd ed., John Wiley & Sons, Inc., 1996. [18] Gandzha, I.; Kadeisvili, J. New Sciences for a New Era: Mathematical,Physical and Chemical Discoveries of Ruggero Maria Santilli: Sankata Printing Press: Nepal, 2011. siNkarma86—Expert Sectioneer of Wikipedia 86 = 19+9+14 + karma = 19+9+14 + talk 20:30, 14 December 2013 (UTC) — Preceding unsigned comment added by ClenserBlastAaa (talk • contribs) I request the administrators to terminate authority to arrogant, dishonest and ignorant members so that I can do the job I first approached you for with respect: finally a due scientific process after one century of organized cosmological adulterations to maintain Einstein's doctrines all over the universe by abusing billions of dollars of taxpayr money. Aabrucadubraa — Preceding unsigned comment added by ClenserBlastAaa (talk • contribs) 21:19, 14 December 2013 (UTC) The first paper is published by the Santilli foundation, which is neither independant of Santilli, nor a reliable source, and what papers Santilli cites is irrelevant. I could write that the moon is made of cheese and cite all the physics nobel prizes and it still wouldn't give my views any credence. Now please stop beating a deadhorse. Headbomb {talk / contribs / physics / books} 22:32, 14 December 2013 (UTC)

Doppler shift interpretation

Recently an IP made some changes to the Doppler interpretation section [2], and I revert them on grounds of accuracy. However, they gave a link to arXiv:0808.1081, which contains very convincing arguments that things can be interpreted as a Doppler shift. I think the section should be rewritten with the arguments made by arXiv:0808.1081 in mind. Headbomb {talk / contribs / physics / books} 14:27, 18 December 2013 (UTC)

Hubble Diagram - in initial explanation why is it not considered to show velocity again time

I visited this page to find why Hubble diagram is not interpreted as expansion velocities being greater the further back in time you look (because light has taken longer to travel from more distant galaxies). The verbal description didn't answer this fairly obvious issue of interpretation. Is it possible to add a little more explanation about how the time aspect of these observations is incorporated in calculation of the Hubble constant, or why it is generally not mentioned in the verbal descriptions aimed at non-cosmologists. Dr S Richardson (talk) 21:37, 3 March 2014 (UTC)

Proposed Changes to "Observed values" table

I believe the dates in the first column should be changed to YYYY-MMM-DD format, ie. 2001-May, 2009-Feb, 2013-Mar-21. At first I thought 2001-05 meant that the data was from the period 2001 to 2005, rather than May 2001. I believe my proposal will improve clarity. Tdf4638 (talk) 22:01, 27 March 2014 (UTC)

Derivation of the Hubble parameter - Needs Reliable Sources

Can someone who knows what they are talking about please check if this edit is correct? Thank you in advance. Richard75 (talk) 17:00, 5 May 2013 (UTC)

Yes, help citing Reliable Sources seems needed for the Hubble's law article - trying to validate derivations seems to be quite a challenge esp since there seems to be few Reliable Sources cited - are some of the derivations and/or uncited statements Original Research? - added several relevant templates ({ {Citation needed |reason=reliable source needed to validate derivation |date=May 2013}}) to the article - in any case - Enjoy! :) Drbogdan (talk) 20:20, 5 May 2013 (UTC)

• No, they are not. This section derivations are quite standard. See most courses on Cosmology, eg. Cambridge Part III — Preceding unsigned comment added by 128.232.251.85 (talk) 14:33, 5 April 2014 (UTC)

Graphic

File:Hubble-constant-vers2.png should be removed as it contains outdated data. Correct (up to date) information is more important to the reader than pretty pictures. 00:08, 10 April 2014 (UTC)

I would argue that it is not "outdated," but "historical" in nature. The entire section the image is found in pertains to the narrowing down of H₀ and the different values researchers have found for it over the years. If anything should be changed it should be the description, so that it is more obvious that there is historical context. In the meantime, I'll start work on an updated graphic. Primefac (talk) 08:50, 10 April 2014 (UTC)

Variable Hubble constant

Since Hubble constant redirects here I suggest making more clear that the Hubble constant is actually not a constant but a variable that is increasing. Thank you 82.20.80.246 (talk) 20:39, 20 December 2014 (UTC)

The "Interpretation" section states this fact, however I see your point that it could potentially be made more clear in the lede. Primefac (talk) 20:51, 20 December 2014 (UTC)

Why the so-called Hubble constant is called a "constant" when it is the inverse of the age of the universe and therefore not at all constant has been a conundrum for me for quite some time now. Only today I discovered the explanation buried in the article. The term is awfully misleading. I have to reiterate the call for making this clearer. The alternative (and far more accurate and less confusing) term "Hubble parameter" should be mentioned, in bold, in the intro. I would do it myself but I feel uncomfortable editing natural science articles (apart from tweaks) because I consider myself anything approaching well-versed only in the social sciences. --Florian Blaschke (talk) 13:32, 23 February 2015 (UTC)

Doppler/redshift

This article defines the Hubble law in terms of Doppler shift, but it properly ought to be redshift or cosmological redshift. While cosmological redshifts and Doppler redshifts are observationally indistinguishable, they have very different causes. Thinking of it in terms of Doppler effect leads to problems. For instance, Doppler shifts greater than the speed of light are not possible, but cosmological redshifts greater than the speed of light are.

74.142.32.130 (talk) 11:47, 5 January 2016 (UTC) Danny Faulkner

In the "combining redshifts" section, it states that it's not actually a Doppler shift, but I can see how just reading the lead may be confusing. Primefac (talk) 15:31, 5 January 2016 (UTC)

Hubble acceleration scale

I've seen in various astrophysical papers[3][4] mention of the "Hubble acceleration scale" a₀ = cH₀ ≈ 6.59×10⁻¹⁰ m/s². I'm guessing this is the gravitational acceleration requires to bind objects together against Hubble expansion, but all the sources I can find are rather technical and don't have a good WP-level explanation of the significance of the number.

It sould definitely be nice to have a subsection on this value. Has anyone got a simple explanation? 71.41.210.146 (talk) 23:36, 11 November 2016 (UTC)

How did Hubble determine distances?

I can't see where this is mentioned here or in the linked articles. — Preceding unsigned comment added by Keith McClary (talk • contribs) 05:19, 2 December 2016 (UTC)

Keith McClary, see Hubble's_law#Cepheid_variable_stars_outside_of_the_Milky_Way. Primefac (talk) 12:46, 2 December 2016 (UTC)

Correction of Hubble law by German astronom Walter Baade

The observations of German astronom Walter Baade led him to define distinct "populations" for stars (Population I and Population II). The same observations led him to discover that there are two types of Cepheid variable stars. Using this discovery he recalculated the size of the known universe, doubling the previous calculation made by Hubble in 1929. He announced this finding to considerable astonishment at the 1952 meeting of the International Astronomical Union in Rome. --AustEngla (talk) 00:25, 11 December 2017 (UTC)

References

Is it possible to have the value of the constant in a different form?

On science shows like 'Cosmos' etc, when they say "if the nucleus was the size of a marble, the stadium size would be the electrons cloud" type of thing? Just a bit more graspable than a megaparsec. The best I got so far was something like, space expands (approximately) 1mm for every 75 million kilometers, per hour? If I did that right. For us laypeople :) just a thought thanks 92.23.182.12 (talk) 11:07, 12 April 2018 (UTC)

How to find the Hubble constant, the easy way.

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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The furthest we can see (in theory) is 13.8 billion light years, the Universe being that old.

Divide that up into megaparsec sections (of 3.26 million light years) and that comes to just over 4,233 sections.

At the furthest point, redshift is light speed as in 298,051 kms per second.

Divide 298,051 by just over 4,223 and you get 70.409 kms per second per megaparsec, the Hubble constant for expansion (185.181.236.222 (talk) 15:39, 18 August 2018 (UTC))

Are you suggesting that this is an easy way others missed? That'll give one an average over the history of the universe if you already know the age, but working backwards from the age of the universe doesn't contribute anything new, as the age itself was determined partly from the methods you may think you're shortcutting. H has also varied over time, so using the relationship between the age and the apparent recession of the CMB is actually complicated by the need integrate the function over the period. The speed of light (c) is actually 299,792 km/s and redshift (z) is a measure of wavelength; perhaps you're talking about the the fact that for a z of 1100, the recession velocity is 0.9999983501099652 * c, but that's still 299791.963375, so I'm confused as to where your "298,051" figure is from. —Undomelin (talk) 22:46, 17 September 2018 (UTC)

There is now a very simple way to calculate Hubble’s Constant, by inputting to an equation, the numerical value of Pi and the speed of light (C) from Maxwell’s equations, and the value of a parsec. NO space probe measurements (with their inevitable small measuring / interpretation errors) are now required. Hubble’s Constant is ‘fixed’ at 70.98047 PRECISELY. This maths method removes the errors / tolerances that is always a part of attempting to measuring something as ‘elusive’ as Hubble’s Constant. This has very deep implications for theoretical cosmology.

The equation to easily and precisely 'fix' Hubble's Constant is 2 X a meg parsec X light speed (C). This total is then divided by Pi to the power of 21. This gives 70.98047 kilometres per sec per meg parsec. Its reciprocal is 13.778 BLY's.

This is known as ‘The Principle of Astrogeometry'. David. David Michael Hine (talk) 17:39, 19 September 2018 (UTC)

This is numerology and is physically meaningless. Headbomb {t · c · p · b} 17:50, 19 September 2018 (UTC)

So by your 'weird reasoning, Maxwell's equations and Relativity must also be 'numerology'? David Michael Hine (talk) 17:54, 19 September 2018 (UTC)

Please indent your talk page messages as outlined in wp:THREAD and wp:INDENT — See Help:Using talk pages. Thanks.

It doesn't really matter. If you have reliable sources (see wp:Reliable sources and wp:Secondary sources) where this is discussed, we might take something onboard in the article. Otherwise we cannot even discuss this here, and this discussion is off-topic. This talk page is for discussions about the article, not about the subject — see wp:Talk page guidelines. - DVdm (talk) 18:05, 19 September 2018 (UTC)

Both relativity and maxwell's equations have sound theoretical and experimental support. The above is just mashing numbers together until you get something close to the value. Headbomb {t · c · p · b} 18:08, 19 September 2018 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.