• IAU: Hubble-Lemaitre Law?

    From Steve Willner@21:1/5 to All on Thu Oct 4 12:57:07 2018
    The IAU is considering recommending that the expansion of the
    universe be referred to as the "Hubble-Lemaitre Law" instead of the
    "Hubble Law." More details, including the resolution text and
    background material, are at https://www.iau.org/news/announcements/detail/ann18048/

    My French isn't as good as I'd like it to be, but in Lemaitre's paper http://adsabs.harvard.edu/abs/1927ASSB...47...49L
    I don't see any data, though the paper summarizes some data from
    Hubble and Stromberg at the top of p 56 (or just above Eq 24 if I'm
    not reading the page number correctly). Am I missing something?

    Any comments on the resolution? If interested, please examine the
    background material linked from the IAU announcement rather than rely
    on my summary.

    --
    Help keep our newsgroup healthy; please don't feed the trolls.
    Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu Cambridge, MA 02138 USA

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  • From Phillip Helbig (undress to reply)@21:1/5 to willner@cfa.harvard.edu on Thu Oct 4 20:12:08 2018
    In article <pp5gue$g00$1@dont-email.me>, Steve Willner <willner@cfa.harvard.edu> writes:

    The IAU is considering recommending that the expansion of the
    universe be referred to as the "Hubble-Lemaitre Law" instead of the
    "Hubble Law." More details, including the resolution text and
    background material, are at https://www.iau.org/news/announcements/detail/ann18048/

    My French isn't as good as I'd like it to be, but in Lemaitre's paper http://adsabs.harvard.edu/abs/1927ASSB...47...49L
    I don't see any data, though the paper summarizes some data from
    Hubble and Stromberg at the top of p 56 (or just above Eq 24 if I'm
    not reading the page number correctly). Am I missing something?

    Lemaitre didn't have any data of his own, but he was the first to
    actually calculate a numerical value for the "Hubble" constant. This
    crucial bit was left out of the English translation for MNRAS, which is
    one reason (Hubble's ego being another) why he wasn't given much credit.
    Also, Hubble---otherwise not one to shy away from glory---remained
    sceptical about the INTERPRETATION of the magnitude-redshift relation he
    (and others) found.

    Why it was left out of the English translation was something of a
    mystery for a while, but has now been solved. Basically, he published a
    paper in French, and it was later translated for MNRAS, but with (from
    today's perspective) the most interesting bit left out. To make a long
    story short, it turned out that he suggested leaving it out, because it
    was of no current interest (he said "actual interest", but since
    "actuel" means "current" in French, that is not what he meant). This is
    an interesting story in itself. Check out Nussbaumer & Bieri's book Discovering the Expanding Universe. I don't have the reference at hand,
    but I believe that it was Mario Livio who solved the mystery.

    See also a post from today on Peter Coles's blog "In the Dark".

    Any comments on the resolution? If interested, please examine the
    background material linked from the IAU announcement rather than rely
    on my summary.

    I think that one could make a case for calling it just Lemaitre's Law.
    On the other hand, I'm not sure how effective such top-down resolutions
    are nor whether, in general, they are a good idea. In this particular
    case, I think that it is justified.

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  • From Richard D. Saam@21:1/5 to All on Sat Oct 6 12:04:49 2018
    On 10/4/18 10:12 PM, Phillip Helbig (undress to reply) wrote:
    In article <pp5gue$g00$1@dont-email.me>, Steve Willner <willner@cfa.harvard.edu> writes:

    The IAU is considering recommending that the expansion of the
    universe be referred to as the "Hubble-Lemaitre Law" instead of the
    "Hubble Law." More details, including the resolution text and
    background material, are at
    https://www.iau.org/news/announcements/detail/ann18048/

    My French isn't as good as I'd like it to be, but in Lemaitre's paper
    http://adsabs.harvard.edu/abs/1927ASSB...47...49L
    I don't see any data, though the paper summarizes some data from
    Hubble and Stromberg at the top of p 56 (or just above Eq 24 if I'm
    not reading the page number correctly). Am I missing something?

    Lemaitre didn't have any data of his own, but he was the first to
    actually calculate a numerical value for the "Hubble" constant. This
    crucial bit was left out of the English translation for MNRAS, which is
    one reason (Hubble's ego being another) why he wasn't given much credit. Also, Hubble---otherwise not one to shy away from glory---remained
    sceptical about the INTERPRETATION of the magnitude-redshift relation he
    (and others) found.

    Why it was left out of the English translation was something of a
    mystery for a while, but has now been solved. Basically, he published a paper in French, and it was later translated for MNRAS, but with (from today's perspective) the most interesting bit left out. To make a long
    story short, it turned out that he suggested leaving it out, because it
    was of no current interest (he said "actual interest", but since
    "actuel" means "current" in French, that is not what he meant). This is
    an interesting story in itself. Check out Nussbaumer & Bieri's book Discovering the Expanding Universe. I don't have the reference at hand,
    but I believe that it was Mario Livio who solved the mystery.

    See also a post from today on Peter Coles's blog "In the Dark".

    Any comments on the resolution? If interested, please examine the
    background material linked from the IAU announcement rather than rely
    on my summary.

    I think that one could make a case for calling it just Lemaitre's Law.
    On the other hand, I'm not sure how effective such top-down resolutions
    are nor whether, in general, they are a good idea. In this particular
    case, I think that it is justified.

    In this continuing discussion towards Lemaitre,
    perhaps Fred Hoyle's physical universe beginning notion
    expressed as the pejorative Big Bang
    will be replaced by George Lemaitre's notion:
    "hypothesis of the primeval atom" or the "Cosmic Egg"
    RDS

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  • From Steve Willner@21:1/5 to helbig@asclothestro.multivax.de on Sat Oct 6 22:21:08 2018
    In article <pp5tic$qc8$1@gioia.aioe.org>,
    "Phillip Helbig (undress to reply)" <helbig@asclothestro.multivax.de> writes:
    Lemaitre didn't have any data of his own, but he was the first to
    actually calculate a numerical value for the "Hubble" constant.

    Thanks. On that basis, it seems to me the response should be to
    change "Hubble constant" to "Lemaitre constant." As an observer, I
    favor those papers that actually present data, so my initial thought
    is that "Hubble Law" should remain.

    Basically, [Lemaitre] published a paper in French, and it was
    later translated for MNRAS, but with (from today's perspective) the
    most interesting bit left out. ... I don't have the reference at
    hand, but I believe that it was Mario Livio who solved the mystery.

    Yes, that's one of the references in the IAU link. Livio's paper is
    behind the _Nature_ paywall, though. I haven't looked for an open
    version.

    On the other hand, I'm not sure how effective such top-down resolutions
    are nor whether, in general, they are a good idea.

    Both valid concerns, to be sure. Probably changing "Hubble constant"
    is more of a stretch than "Hubble law," and that may have influenced
    the IAU body proposing the change.

    Hubble also has a "variable nebula" (NGC 2261 associated with R Mon).
    You missed that one. :-)

    --
    Help keep our newsgroup healthy; please don't feed the trolls.
    Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu Cambridge, MA 02138 USA

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  • From Phillip Helbig (undress to reply)@21:1/5 to Willner on Sat Oct 6 19:47:06 2018
    In article <ppamuh$ibn$1@dont-email.me>, willner@cfa.harvard.edu (Steve Willner) writes:

    In article <pp5tic$qc8$1@gioia.aioe.org>,
    "Phillip Helbig (undress to reply)" <helbig@asclothestro.multivax.de> writes:
    Lemaitre didn't have any data of his own, but he was the first to
    actually calculate a numerical value for the "Hubble" constant.

    Thanks. On that basis, it seems to me the response should be to
    change "Hubble constant" to "Lemaitre constant." As an observer, I
    favor those papers that actually present data, so my initial thought
    is that "Hubble Law" should remain.

    Ironically, many of "Hubble's" redshifts came from other people, often
    without due credit. In the biography Edwin Hubble, Mariner of the
    Nebulae by Gale Christensen (not sure if the spelling is right), he
    comes across as someone who was not only interested in his own fame, but
    was also willing to take credit where it was also due others. He had
    more than enough work of his own to be proud of, but some folks just
    can't get enough. :-|

    See also https://arxiv.org/abs/1307.2289 .

    Both valid concerns, to be sure. Probably changing "Hubble constant"
    is more of a stretch than "Hubble law," and that may have influenced
    the IAU body proposing the change.

    There are two things to keep in mind: the observational relation between redshift and apparent magnitude, and the theoretical relationship
    between velocity and distance. Both are sometimes referred to as
    Hubble's Law. The latter must be completely linear in any model which
    remains homogeneous and isotropic with time; no physics here, only
    kinematics. The former is linear at low redshift (taking redshift as a
    proxy for velocity and apparent magnitude as a proxy for distance). In general, things are more complicated. Probably the best description, as
    is often the case, comes from Ted Harrison:

    @ARTICLE {EHarrison93a,
    AUTHOR = "Edward R. Harrison",
    TITLE = "The Redshift-Distance and
    Velocity-Distance Laws",
    JOURNAL = APJ,
    YEAR = "1993",
    VOLUME = "403",
    NUMBER = "1",
    PAGES = "28",
    MONTH = jan
    }


    Hubble also has a "variable nebula" (NGC 2261 associated with R Mon).
    You missed that one. :-)

    So did Sandage. :-)

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