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Investigations on Proper Motion by Adriaan van Maanen and others
Former title was: On Spiral Nebulae, Adriaan van Maanen et al
Robert S. Fritzius, Shade Tree Physics
Installed 28 September 2003. Latest update 09 Oct 2017.
This research has made use of
NASA's Astrophysics Data System
(NADS) Bibliographic Services.
This page consists of a chronologically ordered bibliography of articles related to the astrometric
measurements of internal motions of stellar systems. (In essense, Adriaan van Maanen resurrected.)
The main area of concern has to do with, but is not limited to, spiral nebulae (currently called galaxies).
Abstracts, highlights, and thumbnail sketches of a number of the articles, are being added.
The compiler of this bibliography is fully aware that, at the present, about 97 percent of the
articles in print since 1935 (and especially those on the world wide web) dealing with van
Maanen's sixteen plus Mt. Wilson papers on internal motions of spiral nebulae (published in the
1916-1930 timeframe), paint him as being mistaken in his findings. In contrast to the majority
opinion against van Mannen, it can be seen that he was not a lone voice crying in the
wilderness. There may even come a need to resume astrometric studies on the internal
motions in spiral nebulae.
Key words: apparent radial velocity, photographs over time, proper motion,
redshift, spiral nebulae,
Bibliography with Abstracts, Highlights, and Thumbnail Sketches
A&A - Astronomy and Astrophysics
AJ - Astronomical Journal
ApJ - Astrophysical Journal
AN - Astronomische Nachrichten
ASPL - Astronomical Society of the Pacific Leaflets
BAN - Bulletin of the Astronomical Institute of the Netherlands
JRASC - The Journal of the Royal Astronomical Society of Canada
MNRAS - Monthly Notices of the Royal Astronomical Society
Obs - The Observatory
PA - Popular Astronomy
PASP - Publications of the Astronomical Society of the Pacific
PNAS - Proceedings of the National Academy of Sciences of the United States of America
Slipher, V. M., "The detection of nebular rotation,"
Lowell Observatory Bulletin, 2, 66 (1914)
[This pertains to the Virgo Nebula, now known as the Sombrero Galaxy, M104.]
Curtis, Heber D., "Proper Motions of the Nebulae," -
[This is a report on an early nebular proper motions study done using
photographs made with the Crossley Reflector at Lick Observatory.] The
average time between early and late plates was
13.85 years. [pp.214-215]
The general results [for average yearly proper motions], by classes are
1. Large, Diffuse Nebulosities: 0."036 - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10 objects.
2. Planetary and Annular Nebulae: 0."028 - - - - - - - - - - - - - - - - - - - - - - - - - 17 objects.
3. Very Small Nebulae (many show evidence of spiral character ): 0."040 - - - - 47 objects.
4. Large Spiral Nebulae: 0."033 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 66 objects.
The accuracy of the measures varies considerably, ... and would be much
higher were the old plates as uniformly sharp and good as the late plates.
A number of the better determined nebulae showing numerous condensations
were examined graphically for possible evidence of rotation, but none were
The average radial velocity of 73 planetary type nebulae . . . is thirty-nine
kilometers per second. This value, combined with the average proper motion
found, would make the average distance of this class of nebulae about one
thousand light years, a value which is not improbable, as all these objects
are Milky Way Phenomena. [p.217]
The radial velocities of very few spirals have been determined as yet; the
mean of SLIPHER'S results is 400 kilometers per second, a truly enormous
value, which may be considerably changed when a larger number have been
determined. On this basis and on the assumption that these objects are
moving truly at random in space, the average distance of the spirals is
of the order of ten thousand light years, a distance that many will regard
as too small. [pp. 217-218]
van Maanen, Adriaan, "List of Stars with Proper Motion Exceeding 0".50 Annually,"
ApJ, 41, 187 (1915)
Porter, J.G., "Note on van Maanen's list of stars with motion exceeding half
a second annually,"
AJ, 29, 46 (1915)
These two articles are included because investigations into nebular motions
hinged on the use of selecting slowly moving foreground stars as a reference
system. [Added 22 March 2010.]
Lampland, C. O., "Preliminary Measures of the Spiral Nebulae N.G.C. 5194
and N.G.C. 4254
for Proper Motion and Rotation,"
PA, 24, 667 (1916)
Pease, Francis G., "The Spiral Nebula Messier 33,"
A spectroscopically determined radial velocity of -278 km/sec for a
bright knot some ten minutes of arc from the nucleus of M33, as compared
to the systemic [motion as a whole] radial velocity of -70 km/sec,
implies some degree of internal motions for the nebula. "Unfavorable
weather has prevented the obtaining of spectra of other knots to determine
whether there is a progressive change in type from the nucleus to the edge
and also whether or not the difference in velocity means a rotation." [See
the (1971) Gordon entry below.]
van Maanen, A., Ritchey, G.W., Keeler, J.E., Perrine, C.D., Curtis, H.D.,
"Preliminary Evidence of Internal Motion in the Spiral Nebula Messier 101,"
ApJ, 44, 210 (1916) -
[Plate VII is not scanned. NADS abstracts does not list van Maanen's
See van Maanen's Plate VII that shows his measurements of
Internal Motions in Messier 101. [This scanned in image,
found with Google.com, was tucked away
in the Astronomy and Astrophysics section of
Science in the Twentieth Century webpages.
Professor Doel kindly disagrees with this compiler's contention that van
Maanen's internal motions of spiral nebulae were unfairly treated by his
Underwood, Ralph, "A determination of the proper motion of three faint stars near Sirius"
PA, 25, 481 (1917)
[Master's Thesis Submission: University of Minnesota]
Barnard, E. E., "The Proper Motion of the Great Nebula of Andromeda,"
AJ, 30, 175-176 (1917)
"Though the distances are discordant, they show that no considerable
relative motion has occurred in the past eighty years."
Jeans, J. H., "Internal Motion in Spiral Nebulae,"
Kostinsky, S., "Probable Motions in the Spiral Nebula Messier 51 (Cannes
Venatici) Found With the Stereo-comparator. Preliminary Communication,"
MNRAS, 77, 233 (1917)
Stereoscopic comparison of plates of Messier 51, taken in March 1896 and
in April 1916, found "almost indisputable displacements of some
characteristic knots lying on the spirals."... "Preliminary stereoscopic
measures on the above-mentioned plates of 36 single knots showed me that
their observed proper motions with regard to the centre of the nebula
seem to have a systematic character in the different parts. They led
me to the following preliminary conclusions: -
(a) On the outer spiral the motion proceeds as though in general
the single parts were moving away from the centre, so that the spiral
has a tendency to draw itself together in the direction opposite
to the hands of a clock;
(b) On the contrary, on the inner spiral in its eastern part the
motion towards the centre prevails, and if there is any tendency to draw
together it is rather in the opposite direction, i.e. with the
hands of a clock;
(c) In the mean the annual proper motions of the single knots and
stars are of the order of 0".04 - 0".05, but vary within wide limits.
Shapley, Harlow, "Note on the Magnitudes of Novae in Spiral Nebulae,"
PASP, 29, 213-217, (1917)
Their authenticity [eleven novae in spiral nebulae] can hardly be doubted,
. . . On the basis of chance, Curtis has noted the
impossibility of considering these novae [to be] physically unrelated to
the spirals with which they are associated. [p. 214]
Taking the averages as referring to similar luminosity, possibly an
uncertain procedure . . . , we observe that the difference in apparent
brightness calls for a distance at least 50 times as great for these
larger spiral nebulae as for the average novae of the galactic system.
If we are to believe that a spiral nebula, . . . , is a remote stellar
system, its most luminous stars must be fainter than magnitude 21, since
even in its thinner parts there is no hint of resolution into distinct
stars on the best of plates; nor can the nebulous condensations, with
magnitudes between 15 and 20, be considered an accumulation of stars
brighter than magnitude 21. This point is important, for, if in the
hypothetical galactic system the brightest stars are comparable with
the bright stars of our own galaxy, the minimum distance of the Andromeda
Nebula must be of the order of a million light years.
van Maanen, A., "Investigations on proper motion. First paper: The motions of 85 stars
in the neighborhood of Atlas and Pleione,"
Contributions from the Mount Wilson Observatory / Carnegie Institution of Washington,
vol. 167, pp.1-15 1919)
Atlas and Pleione are members of the Plieades group. "Of the 85 stars,
down to magnitude 15.7, which were measured in a region of the Plieades, five
show proper motions equal to the group." (P. 419)
van Maanen, A., "Investigations on proper motion. Second paper: The motions of 162 stars
in the neighborhood of the Orion Nebula,"
Contributions from the Mount Wilson Observatory / Carnegie Institution of Washington, vol. 168, pp.1-15 (1919)
Schouten, W.J.A., "Probable Motions in the Spiral Nebula Messier 51
Obs, 42, 441-444 (1919)
"The numerous measures performed by Mrs. Dorothea Roberts on photographs of
Messier 51 (Rivista di Astronomia, 1910, pp. 31-41 & 62-85) have
been published in a form making it impossible (alas!) to deduce the
proper-motion of the nebulous points. Therefore we have not been able
to compare our results with hers. Kostinsky (Monthly Notices,
1910, pp. 31-41 & 62-85)* has found annual motions of the order
0".04 - 0".05 for a number of points in Messier 51. This agrees with our
"The rotational movement (2) found for the nebula Messier 51 is considerably
smaller than that determined by Dr. van Maanen (Contr. Mount Wilson
Observ. No. 118) for the spiral nebula
* [Year and page numbers are typographical repeats from
Shouten's first reference in the previous sentence. The actual
reference is: MNRAS, 77, 233 (1917).]
van Maanen, A., Willis, H.C., Oosterhoff, P.T., Investigations on Proper
Library of Congress Call Number QB4.M93 no. 167-168, (1919)
[Abstract not available.]
van Maanen, A., "Evidence of Stream Motion Afforded by the Faint Stars Near the Orion Nebula,"
PNAS 5, 225 (1919)
Curtis, Heber D., "Modern Theories of the Spiral Nebulae,"
14, 317-327 (1920)
The most anomalous and inexplicable feature of the spiral nebulae is found
in their peculiar distribution. They show an apparent abhorrence for our
galaxy of stars, being found in greatest numbers around the poles of our
galaxy. In my counts I found an approximate density of distribution as
Galactic Latitude +45° to +90° - - - - - - - - - - - - - - - - - - - - - 34 per square degree.
Galactic Latitude –45° to –90° - - - - - - - - - - - - - - - - - - - - - 28 per square degree.
Galactic Latitude +30° to +45° and –30° to –45° - - - - - - - - - 24 per square degree.
Galactic Latitude –30° to +30° - - - - - - - - - - - - - - - - - - - - - - 7 per square degree.
van Maanen, A., "Internal Motion in Four Spiral Nebulae,"
33, 200 (1921)
For the rotational and radial components the results are collected in
Table I. The rotational components would
correspond to the following periods: For Messier 101, 85,000 years;
for Messier 33, 160,000 years; for Messier 51, 45,000 years;
for Messier 81, 58,000 years.
van Maanen, A. "Investigations on proper motion. Third paper: The proper motions of stars
in and near the double cluster in Perseus",
Contributions from the Mount Wilson Observatory / Carnegie Institution of Washington, vol. 205, pp.1-29 (1921)
van Maanen, A., "Investigations on Proper Motion - Fourth Paper: The Internal Motion in the Spiral Nebula Messier 51,"
A comparison of a plate taken by Mr. Duncan on April 8, 1921, with one
taken by Mr. Ritchey on February 7-8, 1910, both at the 25-foot focus of
the 60-inch reflector, enabled the proper motion of the nebula
and the relative motion of its parts to be determined. Measurements of
80 points of the nebula compared with those of 20 stars give for the nebula
an annual proper motion of +0".006 in right ascension and +0".001 in
declination. The internal proper motion is not a pure rotation
since the mean radial component is outward and is 42 percent of the mean
tangential component which is 0".019 ENWS; rather it is a spiral
motion out along the arms at the rate of 0".021 per year together with
a slight outward radial motion of 0".003.
Two sixteenth magnitude stars with large proper motions, about
0".15 per year, were found near Messier 51. They are called
f and r.
[Plate II (in hardcopy original) shows internal motions of M51.]
[With respect to his selected reference stars, van Maanen's measures of
bulk internal motions for M51 are approximately three times greater
than his measure of its systemic proper motion..]
van Maanen, A., "Investigations on Proper Motion - Fifth Paper: The
Internal Motion in the Spiral Nebula Messier 81,"
See related pages:
[Plate IV (in hardcopy original) shows internal motions of M81.]
Table III - Summary of Internal Motions in Spiral
M81 Internal Motions, van Maanen (Follow-up on
Cosmology's Missing Mass Problems
Lundmark, Knut, "The Spiral Nebula Messier 33,"
On small scale photographs the spiral appears as a bona fide nebulous
object but photographed with large instruments especially the outer parts
of the spiral arms seem to be resolved into numerous star-like objects.
Many of these secondary nuclei look exactly like stars but a number of
them have a soft appearance which has led Ritchey to call them nebulous
stars. . . .
There is in the spiral structure a great number of dark lanes and it is to
be noted that these do not always define the space between the spiral arms
but many times go across them. . . .
[To see an example of a dark lane cutting across spiral arms, see
Robert Gendler's CCD
M81, Spiral Galaxy in Ursa Major.]
[To this writer, the cross-cutting dark lane phenomenon is
suggestive of a wake-like action caused by the rapid passage of some
massive object (or a compact system of objects) skimming across the
face of a spiral. The object transient time would have to be
much shorter than the rotation period of the spiral, otherwise the trace
would be curved by the differential motions in the spiral arms. If this
is the case, it absolutely requires that the spirals have the
relatively small spatial dimensions and distances from us,
consistent with van Maanen's findings. RSF 25 Oct 2003.]
From an unpublished investigation on the proper motion of 100 spiral
nebulae, derived from micrometric and photographic measures, we give the
following results for N.G.C. 604
nebulous star forming region in M33] measured as one mass to
illustrate the accuracy of the measures. [The units are in decimal
fractions of arcseconds per year.] [p. 326]
[Note that Lundmark seems to have no problems with annual proper
that are much smaller than the nominal one arcsecond limit for ground
van Mannen, A., Investigations on proper motion. Sixth paper:
The motions of 65 stars in the neighborhood of 65 Tauri",
Contributions from the Mount Wilson Observatory / Carnegie Institution of
Washington, vol. 224, pp.1-7 (1922)
van Maanen, A., "Investigations on Proper Motion - Seventh Paper:
Internal Motion in the Spiral Nebula NGC 2403,"
van Maanen, A., "Investigations on Proper Motion - Eighth Paper:
Internal Motion in the Spiral Nebula M94=NGC 4736,"
Jeans, James Hopwood.,
The Nebular Hypothesis and Modern Cosmogony: Being the Halley Lecture delivered
on 23d May 1922, Oxford, The Clarendon Press, London, New York [etc] H. Milford (1923). [No
article or abstract available.]
Jeans, J. H., "Internal Motions in Spiral Nebulae,"
MNRAS, 84, 60 (1923)
No interpretation, and very little discussion, has so far appeared on
Mr. van Maanen's highly interesting measurements of the internal motions of
spiral nebulae. ... The theoretical part of the present paper has been held
back for over a year, the first part of which was spent in an unsuccessful
effort to find some less revolutionary interpretation of the observed
motions than that here tentatively put forward, the second part being spent
in an effort, again unsuccessful, to connect up the suggested interpretation
with the general scheme of the theory of relativity....[p. 60]
[More to come.]
van Maanen, A., "Investigations on Proper Motion - Ninth Paper:
Internal Motion in the Spiral Nebula Messier 63, NGC 5055,"
ApJ, 57, 49 (1923)
van Maanen, A., "Investigations on Proper Motion - Tenth Paper:
Internal Motion in the Spiral Nebula Messier 33, N.G.C. 598,"
ApJ, 57, 264 (1923)
Comparison of two photographs taken in 1910 and 1922 by Ritchey and
Humason, respectively, gives, with respect to twenty-four comparison
stars, the annual proper motion of
and the motions of 399 nebular points freed from this motion. The internal
motions are shown on Plate XIX. They can be interpreted as a rotation or
as a motion outward along the arms of the spiral, preferably the latter.
Taken as a rotation, the motions indicate periods from 60,000 to 240,000
years. [p. 264]
See M33 Internal Motions according to van Maanen
Excel spreadsheet for reference stars
There seems to be a considerable increase of motion with distance from the
center. Error analysis of measured displacements within seven spirals
indicates that actual internal motions exist and are in agreement with
Jeans' cosmogony. Parallaxes of larger spiral nebulae suggest diameters
ranging from several light years to several hundred light years. Larger
spirals are enormous compared to our solar system, but are small compared
to the Milky Way. [p. 264.]
For internal motions expressed as rotation (+ = N-E-S-W) and radial
(+ = outward) components, the component means were found to be
rotation = +0.020 ± 0.001 arcsec/year,
radial = +0.003 ± 0.001 arcsec/year. [p. 273.]
Jeans J. H., "Note on the Distances and Structure of the Spiral Nebulae,"
MNRAS, 85, 531 (1925)
Results recently published by Hubble and Shapley seem to establish the
inaccuracy of estimates I made some time ago of the distances and other
quantities associated with the spiral nebulae. Hubble estimates
the distance of M 31 (the Andromeda nebula) as 950,000 light-years, as
against my estimate of 5000 light-years. Even apart from this, however,
the time has come when my calculations may reasonably
be revised in the light of new nebular knowledge. . . .
My original calculations made use of v. Maanen's determinations of the
angular velocities of the nebulae. Recently Eddington has drawn attention
to the close correlation between the luminosities and masses of actual
stars. If the same correlation is assumed to hold for the stellar
condensations in a nebula, we can dispense with v. Maanen's measurements
altogether and (in theory at least) determine the distance of the nebula
from the observed stellar magnitudes of its condensations. The method is
[Method is described]
The method, although simple in theory, may encounter in practice a
difficulty which may render it almost valueless. [Describes the potential
[In a footnote Jeans says, "The controversy does not appear to be one
between Professor Shapley and myself, so much as one between the estimates
of van Maanen and Hubble as to nebular distances."]
[Using Pease's formula for line-of-sight velocity as a function of angular
distance from the center of M31, and Hubble's estimated distance to the
same object, Jeans arrives at a rotation period for M31 of 18 million
years.] [pp. 533-534]
It is difficult to imagine that those nebulae which exhibit a lenticular
centre and filamentous arms with pronounced condensations can have a
similar constitution [to that of our galactic stellar system and perhaps
to the nucleus of the Andromeda nebula]. It seems more likely that the
Andromeda nebula may be in a far later stage of development than the
typical spiral; it may exemplify a state intermediate between the typical
spiral and the galactic system. [p. 534]
van Maanen, A., "Investigations on Proper Motion - Eleventh Paper:
The Proper Motion of Messier 13 and its Internal Motion,"
ApJ, 61, 130 (1925)
Lundmark Knut, "Internal Motions of Messier 33,"
ApJ, 63, 67 (1926)
[T]he motion of translation--the total proper motion of the nebula--was
found to be
= -0.0015 arcsec/year;
= -0.0050 arcsec/year, which
is in good agreement with the corresponding values of van Maanen, namely
+0.0034 arcsec/year and -0.0044 arcsec/year, respectively. Internal motions
were found to be: rotation = +0.0016 arcsec/year (NESW), and
radial = - 0.0057 arcsec/year (outward). [The negative
outward measurement may be interpreted as representing an inflowing motion.]
Hubble, E.P., "No. 310. A spiral nebula as a stellar system. Messier 33,"
Contributions from the Mount Wilson Observatory / Carnegie Institution
of Washington, 310, pp. 1 (1926)
Hubble, E. P., "The Spiral M33 as a Stellar System,"
ApJ, 63, 236-274 (1926)
The present contribution to the subject consists of observational data
concerning the particular spiral, Messier 33. The data lead to a
conception of the object as an isolated system of stars and nebulae,
lying far outside the limits of the galactic system. To this extent
the evidence favors the island-universe hypothesis, but, in
respect to dimensions and luminosity, the spiral is more closely
comparable with the Magellanic Clouds than with the galactic system
itself. [p. 237. Also, see pp. 273-274.]
The ratio of minor to major axis appears to be about 2:3; the tilt is
therefore about 42°, and the differential velocity of 200 km/sec can be
interpreted as the radial component of a linear velocity of rotation
about the nucleus of
200 sec 42° = 270 km/sec. ??
This corresponds to a period of rotation on the order of twenty million
years at a distance of 1.83 x 108 astronomical units from the
nucleus. ... [p. 268]
Six stars within 11' of the nucleus show conspicuous proper motions on the
blink comparator on plates of fifteen years' interval made with the 60-inch
reflector. The photographic magnitudes of two have been measured as 17.3
and 18.25, the proper motions being of the order of 13" and 10" per century,
both toward the south-following quadrant. The brighter of these is No. 367
in van Maanen's measures of Messier 33 for rotation[*]
Astrophysical Journal, 57, 264, (1923).
The magnitudes of the other four are estimated to be 14.2, 15.8, 16.4,
and 17.8, with proper motions between 5" and 10" per century. [p.269.]
*[Strictly speaking, van Maanen was not looking for rotation, rather
he was seeking to characterize internal motions whatever their form. To
say that van Maanen was doing measures of rotation is to ignore the
thrust of his investigation. Further evidence of a lack of communication
between Hubble and van Maanen (or something worse) can be seen on page 270.
There, Hubble concludes that it is probable that such rapid stars
(as mentioned in the preceding paragraph) belong to the nebula. Actually,
van Maanen omitted his star No. 367 from the internal motions analysis
because its proper motion was so large that he felt it couldn't be
part of the nebula. See the last sentence on page 265 of van Maanen's
Tenth Paper (1923). ]
[See: Messier 33 Internal Motions on this website.
Lundmark, Knut, "Studies of Anagalactic Nebulae - First Paper,"
Nova Acta Regiae Societatis Scientiarum Upsaliensis, Volumen
Extra Ordinem Editum, (1927).
van Maanen, A., "Investigations on Proper Motion - Twelfth Paper:
The Proper Motions and Internal Motions of Messier 2, 13, and 56,"
Contributions from the Mount Wilson Solar Observatory, 66,
89-112, (1927); ApJ, 66, 89 (1927)
van Maanen, A., "Investigations on proper motion. Thirteenth paper: The proper motion of N.G.C. 2264,
Contributions from the Mount Wilson Observatory / Carnegie Institution of Washington, vol. 405, pp.1-6 (1930)
van Maanen, A., "Investigations on proper motion. Fourteenth paper: The proper motion
of six planetary nebulae,"
Contributions from the Mount Wilson Observatory / Carnegie Institution of Washington,
vol. 406, pp.1-6 (1930)
Lindblad, Bertil, "On the Nature of the Spiral Nebulae,"
87, 420-426 (1927)
In his Leçons sur les Hypothèses Cosmogoniques, p. 262, Poincaré
attempts to draw a parallel between the figure of a rotating stellar
system and the figure of equilibrium of a rotating incompressible liquid.
The stellar system is considered in the picture of a gaseous mass with
stars as molecules. ...
The possibility of explaining the spiral arms rests in this case on
principles quite different from those suggested by Poincaré. Our point
of departure is simply a theorem on the motion of a material particle
under gravitation in the equatorial plane outside of a homogeneous
spheroid. ... [p. 422]
A comparison between such orbits [described above] and the spiral arms of
the nebulæ Messier 33 and 81 was made in the paper cited. ...[p. 423]
[This may be Hubble, E., ApJ, 64, 349 (1926) or it may refer
to an unpublished statistical investigation by Lundmark. Checking.]
It may be remarked that the arms evidently wind out form the "mother-system"
in the same direction as the rotation of the system, while the opposite is
the case according to the suggestion by Poincaré.
The present theory connects a multitude of facts concerning our stellar
system [the Milky Way galaxy] and the spirals, which have only been touched
upon very incompletely in this exposition of the general principles. With
full appreciation of the beautiful* theory of Jeans, I have therefore
ventured to give the present account of the theory which treats the problem
from an older, though considerably modified, point of view. [p. 426]
* [Beware of unrequired adjectives!] [This seems to be one of the seminal
papers in the development of one of
cosmology's missing mass problems.]
Brown, E. W., "Gravitational Motion in a Spiral Nebula,"
51, 277-286 (1928)
[No abstract or article.]
Curtis, Heber D., "The Unity of the Universe,"
Hubble, E. P., "A Spiral Nebula as a Stellar System, Messier 31,"
ApJ, 69, 103 (1929)
Resolution. -- The outer regions of the spiral arms are
partially resolved into swarms of faint stars, while the
nuclear region shows no indications of resolution under
any conditions with the 100-inch reflector. Intermediate regions
show isolated patches where resolution is pronounced or suggested.
Distance of M31 derived from Cepheid criteria. -- Comparisons of
period-luminosity diagrams indicate that M31 is about 0.1 mag. or 5
percent more distant than M33, and about 8.5 times more distant than the
Small Magellanic Cloud. Using Shapley's value for the cloud, we find
the distance of M 31 to be 275,000 parsecs.
Relative dimensions of M31 and the galactic system. -- A tentative
comparison of sizes, masses, luminosities, and densities suggests that
the galactic system is much larger than M31 but that the ratio is
not greater than that between M31 and other known extra-galactic systems.
Early visual observers of the spectrum reported bright lines on a
continuous background. In 1899, however, Scheiner photographed the now
familiar solar-type absorption spectrum and announced emphatically that
the nebula must be a system of stars. Radial velocities of the order of
-300 km/sec. have since been measured by several observers. ... The linear
velocity of rotation as indicated by the measures is of the order of 0
.48x km/sec., where x is the distance from the nucleus in
seconds of arc. The measures extend to about 150" from the nucleus, and
the rotation is in the sense that the south preceding end of the nebula
is approaching us relative to the nucleus. [pp 104-105]
Hubble, Edwin P., "A Relation Between Distance and Radial Velocity among
PNAS, 15, 168 (1929) -
[PNAS PDF. Subscription needed.]
Markov, A., "On the Nature of Spiral and Gaseous Nebulae,"
234, 329 (1929)
Markov, A., "Verbesserungen zu dem Artikel (On the Nature of Spiral and
AN, 234, 329 (1929)
Perrine, C. D., "The Motions and Status of the Spiral Nebulae and Globular
AN, 236, 329 (1929)
Lemaître, Georges, "On the Random Motion of Material Particles in the
Expanding Universe. Explanation of a Paradox,"
BAN, 5, 273 (1930)
Perrine, C. D., "The High Velocities of the Spiral Nebulae,"
AN, 240, 319 (1930)
van Maanen, A., "Investigations on proper motion. Fifteenth paper: The proper motion of the spiral
nebula N.G.C. 4051,"
Contributions from the Mount Wilson Observatory / Carnegie Institution of Washington, vol. 407,
van Maanen, A., "Investigations on Proper Motion - Sixteenth Paper:
The Proper Motion of Messier 51, NGC 5194,"
Contributions from the Mount Wilson Solar Observatory, 408, 1 (1930)
Humason, Milton L., "Apparent Velocity-Shifts in the Spectra of Faint
ApJ, 74, 35-42 (1931)
With one exception, possibly the velocity of an isolated object seen in
projection on a remote cluster, the new data fully confirm the
velocity-distance3 previously formulated and extend the
observational range to a distance of about thirty-two million parsecs.
3It is not at all certain that the large red-shifts observed
in the spectra are to be interpreted as a Doppler effect, but for
convenience they are expressed in terms of velocity and referred to as
Lemaître, Georges, "Expansion of the Universe, A Homogeneous Universe of
Constant Mass and Increasing Radius accounting for the Radial Velocity
of Extra-galactic Nebulæ,"
MNRAS, 91, 483 (1931)
According to the theory of relativity, a homogeneous universe may exist
such that all positions in space are completely equivalent; there is no
center of gravity. ...
Two solutions have been proposed. That of de Sitter ignores the existence
of matter and supposes its density to be equal to zero. It leads to special
difficulties of interpretation ... but it is of extreme interest as
explaining quite naturally the observed receding velocities of
extra-galactic nebulæ, as a simple consequence of the properties of the
gravitational field without having to suppose that we are at a point
of the universe distinguished by special properties.
The other solution is that of Einstein. It pays attention to the evident
fact that the density of matter is not zero, and it leads to a relation
between this density and the radius of the universe. This relation
forecasted the existence of masses enormously greater than any known at
the time. These have since been discovered, the distances and dimensions
of extra-galactic nebulæ having become known. From Einstein's formulæ and
recent observational data, the radius of the universe is found to be some
hundred times greater than the most distant objects which can be
photographed by our telescopes. . . .
Lemaître, Georges Edouward, "Discussion on the Evolution of the Universe,"
[States the theory of the Big Bang.]
[The following two papers are products of the imposed settlement
between Hubble and van Maanen on the issue of astrometric evidence of
internal motions in spiral nebulae. See: Hubble's Demolition of van
Maanen? on this website's Cosmology's Missing
Mass Problems page. Scroll down about 2/3rds of the way from the top
of that page.]
Hubble, E., "Angular Rotations of Spiral Nebulae,"
van Maanen, A., "Internal Motions in Spiral Nebulae,"
336-337 (1935) -
Hubble, Edwin, The Realm of the Nebulae, Yale University Press,
New Haven (1936), Page 141.
Messier 33 -- ...The nucleus resembles in appearance a
giant globular cluster, although no evidence of resolution is found. It is
semistellar, M = -8, spectral type F5, color excess-appreciable,
radial velocity, -320 km/sec.*, as derived from moderately large-scale
* [A recent best value for M33's systemic heliocentric radial
velocity is -180 km/sec. Hubble's disparity may need explaining. See
the Gordon (1971) entry below.]
Humason, Milton L., "Is the Universe Expanding?,"
The interpretation of these recessional velocities beyond the observable
facts is still controversial. So far as is known at the present time,
the only cause which can produce the observed displacements of the lines
in the spectrum of a nebula is motion toward or away from us. On the
assumption that the displacements represent motion, the observations tell
us that almost without exception the extra-galactic nebulae are moving
away from us. The most reasonable explanation of this fact at present
is that the universe is expanding. [p. 164]
. . . If the displacements are not interpreted as motion, we find
in the redshifts a hitherto unrecognized and highly important phenomenon
whose implications are unknown. [p.164]
Zwicky., F., "On the Masses of Nebulae and of Clusters of Nebulae,"
ApJ, 86, 217 (1937)
Lindblad, Bertil, "On the State of Motion in the Stellar System and the
Probable Relation of the Galaxy to the Sequence of Types of Spiral
POBV Conference, 1 September (1938), Page 15 [No
abstract or article.]
Babcock, Horace W., "Spectrographic Observations of the Rotation of the
Andromeda Nebula," (Abstract)
PASP, 50, 174-175 (1938)
The central core of the nebula, to a radius of some 4', appears to rotate
with constant angular velocity, in agreement with the results of Pease.
A linear velocity of rotation of 90 km/sec in the plane of the spiral is
measured at this distance. From this point the velocity falls off,
reaching zero at a distance of 10' from the center. Beyond 10', the
velocity increases again, in the same direction, and from 22' to 30'
maintains a value of about 150 km/sec. [p. 175]
Lindblad, Bertil, "On the Interpretation of Spiral Structure in the
ApJ, 92, 1 (1940)
Previous work had indicated that the full development of spiral structure
is likely to give an approximate logarithmic shape of the arms, in which
the particles of the arm describe roughly circular orbits of uniform angular
velocity around the center. It is concluded here that such a formation
is possible. . . .[p.1]
The verification of the theoretical results by observational data is
discussed in some detail. H. W. Babcock's results concerning the rotation
of the Andromeda nebula are in good agreement with the main theoretical
result concerning the possibility of a uniform rotation of the spiral
Mayall, N.U. and Aller, L.H., "The Rotation of the Spiral Nebula
ApJ, 95, 5 (1942)
...the velocity of the system is found to be -167 ±5 km/sec...
the main body of the spiral, some 18' in radius, appears to
rotate [based on spectroscopic measurements and assumption of simple
circular motion in the plane] almost like a solid body (rotational velocity
increases fairly uniformly with distance), while the outer parts,
represented by a zone having least and greatest radii of 18' and 30'
respectively, appear to rotate like a planetary system (rotational velocity
decreases with distance). The transition between these two types of motion
occurs in the general vicinity of 16' (1000 parsecs) from the center, at
which the rotational velocity attains a maximum of approximately
120 km/sec. ... In most of these [earlier] investigations [with the
exception of Babcock's study of the Andromeda nebula] the rotational
velocities were measured only in the immediate vicinity of the nucleus.
Joy, Alfred H., "Adriaan van Maanen, 1884-1946,"
[According to Joy, van Maanen died of a heart attack on
January 26, 1946. His article is a tribute to van Maanen's scientific
career. The following quote from the article deals with van Maanen's
long term study of internal motions of spiral nebulae.]
"From 1914 until 1923, in addition to his parallax program, he [van Maanen]
spent a great amount of time and effort in an attempt to measure the
internal motions in spiral nebulae by comparing plates taken at different
epochs from 5 to 15 years apart. Although the material was not homogeneous,
some of the plates being taken at the Cassegrain focus, some at the
Newtonian, and some even with other instruments, the results were strangely
accordant in showing a rotation period of the order of 100,000 years or,
perhaps a motion outward along the arms of the spirals. Slow as this
motion is, it is much too rapid to be admitted with our present knowledge[*]
of the distances of these extragalactic bodies. The fact seems to be that
the time intervals between the plates were too short and the observational
material inadequate to cope with the difficulties of the problem. For the
present, at least, we shall have to rely on spectroscopic results for our
picture of the motions in the spiral nebulae." [p. 109]
*[This would be knowledge based on redshifts being used as measures
of cosmological distance. Arp's discordant redshifts, regardless of their
ultimate cause, may eventually lead to a re-evaluation of van Maanen's
See: Arp, Halton,
Seeing Red: Redshifts, Cosmology and Academic Science;
Apeiron, Montreal (1998), and Arp, Halton,
Research with Fred.[Fred Hoyle]
Milne, E. A., "Star-streaming and the Stability of Spiral Orbits in Spiral
Nebulae I - Motion round a point-nucleus,"
MNRAS, 108, 309 (1948)
Gordon, Kurtiss J., "History of our Understanding of a Spiral Galaxy:
Messier 33," QJRAS, 10, 293-307 (1969) -
Smith, M.G., Weedman, D.W., "Internal Motions in Galactic and Extragalactic
H II Regions,"
ApJ, 161, 33 (1970)
Emission profiles have been observed for the total Hα emission from
nine H II regions in the galaxies M101 and M33. ... The most probable
velocities of internal motions are found to range from 19 to 34 km
sec-1. [Added 07 Feb 2007.] [Chandar (2002) found young cluster
velocities of 87 ± 11 km sec-1 in M33.]
Berendzen, Richard,; Hoskin, Michael, "Hubble's Announcement of Cepheids
in Spiral Nebulae,"
ASPL, 10, 425 (1971)
Gordon, Kurtiss, J., "A 21-CENTIMETER Study of the Spiral Galaxy Messier 33,"
ApJ, 169, 235-270 (1971)
The "best value" for the systemic radial velocity of M33 is S = -180 km/sec
(heliocentric). The rotation peaks at Vr = S ± ~85 km/sec at 30'
from the galactic center. ...Velocities in the wings deviate by 40-50
km/sec from those predicted by the rotation curve. [Measures of the
systemic velocity for M33, since 1942, have been within eight percent of
Gordon's "best value" of -180 km/sec. It is of interest to note that
in 1916 Pease's measurement was -70 km/sec and in 1936 Hubble's stated
value was -320 km/sec. Hubble did not specify who made the
See: Systemic Radial Velocity Measurements of
Messier 33. [This website]
Hart, Richard Cullen, "Adriaan van Maanen's Influence on the Island-Universe
Theory," Thesis (Ph.D.)--Boston University Graduate School, (1973).
Dissertation Abstracts International, Volume: 34-04,
Section B, page: 1356 (1973) [No abstract or article.]
Berendzen, R., Hart. R., "Adriaan van Maanen's Influence of the Island Universe Theory: Part 2,"
Journal for the History of Astronomy, 4, 73 (1973).
Hetherington, Norriss S., "Edwin Hubble on Adriaan van Maanen's Internal
Motions in Spiral Nebulae," Isis, 65, 390-393 (1974)
[Added 12 Apr 2007.]
Faber, S. M., Gallagher, J. S., "
Masses and Mass-to-Light Ratios of Galaxies," Annu. Rev. Astron.
Astrophys. 17, 135-187 (1979).
Sulentic, Jack W., Arp, Halton, and Lorre, Jean, "Some Properties of
the Knots in the M87 Jet,"
ApJ, 233, 44-55 (1979)
Photographs taken in 1956 by Baade show the knots in the jet of M87 to be
polarized. In 1978, these plates were repeated under the conditions as
identical as possible. A careful comparison indicates that the
polarization and intensity of the knots have changed in the 22 year
interval. . . . [p. 49]
ii) Proper Motion in the Jet - Measurements were made of the
separation of knot A from the nucleus of M87 in order to see if the knots
had shown detectable radial motion over the 22 year time scale. . . .
[The investigation seems to have evolved into seeing whether or not
there was a measurable change in the angular distance between knots A and B
in the jet. No quantitative result for proper motion, null or otherwise,
for knot A with respect to the nucleus was published.]
No evidence of a separation change [between knot A and B] was
found. . . . [p. 49]
Rohlfs, K. and Kreitschmann, "A Two Component Mass Model for M81 (NGC 3031),"
A&A, 87, 175-182 (1980)
By combining radial velocity data of optical and radio measurements with
resolution ranging from a few arc seconds to 9' a well determined rotation
curve of M81 has been compiled that shows rather clearly two maxima located
at R=1kpc and R=6.5kpc. [The rotation curve is shown on page
176 of ref.] ...
Unfortunately the distance to M81 is still not well determined, we will
adopt here the usual value of D=3.25 Mpc (Tammann and Sandage,
1968) resulting in a scale of 0.945 kpc/arcmin. [p.175] [A comparison of
the details of the two maxima above will be made with
van Maanen's internal motions for M81.]
Berendzen, Richard; Seeley, Daniel, Man Discovers the Galaxies,
Columbia University Press (1984) - Key words and phrases: Slipher,
spiral nebulae, Kapteyn, van Maanen, Maanen, globular clusters, Shapley,
proper motions, nebulae, Mt. Wilson, Lundmark, radial velocites, Trumpler,
internal motions, Cepheids, Edwin Hubble, Albert Einstein, Harlow Shapley,
Huntington Library, United States - Keywords are searchable online at
Search. - [Added 12 Apr 2007.]
Smith, Robert W., "The Expanding Universe. Astronomy's 'Great Debate'
1900-1931," 4S Review, 2, 15-17 (1984) - Available online
through JSTOR. [Added 12 Apr 2007.]
Van den Bergh, Sidney, "Novae, Supernovae, and the Island Universe
PASP, 100, 8 (1988)
Brashear, Ronald W., Hetherington, Norriss S., "The Hubble-van Maanen
conflict over internal motions in spiral nebulae: yet more information on
an already old topic," Vistas in Astronomy, 34, 415-423 (1991)
[Added 12 Apr 2007.]
Hetherington, N., and Brashear, R., "Walter S. Adams and the Imposed
Settlement Between Edwin Hubble and Adriaan van Maanen," Journal for
the History of Astronomy, 23, 53-56 (1992) - [See the 1935
Hubble and van Maanen entries above.]
Kroupa, P., Röser, S., and Bastian, U., "On the motion of the Magellanic
MNRAS, 266, 412-420 (1994)
We have measured the proper motion of the Large and Small Magellanic Clouds
using Magellanic Cloud stars in the PPM Catalogue, and obtain mu =
1.7 +/- 0.9 mas/yr for the LMC. [Added 27 Jul 2006.]
Jones, B.F., Klemola, A.R., & Lin, D.N.C., "Proper Motion of the Large
Magellanic Cloud and the mass of the galaxy. 1: Observational Results,"
AJ, 107, 1333-1337 (1994)
We have measured the proper motion of the Large Magellanic Cloud (LMC)
using 21 plates taken with the Cerro-Tolodo Inter-American Observatory
(CTIO) 4 m telescope and covering an epoch span of 14 yr. The mean absolute
proper motion of the LMC stars in our region is mualpha =
0.120 sec +/- 0.029 sec/century, mudelta =
0.26 sec +/- 0.027 sec/century.
[Added 27 Jul 2006.]
Larson, Richard B., "Formation of Small and Large Stellar Systems,"
Current evidence indicates that stars form in a hierarchy of groupings of
various sizes, within which binary systems stand out as distinct tightly
bound units. The distribution of separations of binaries resembles the
internal spatial distributions of stars in larger systems, including massive
young star clusters and elliptical galaxies, and this suggests that similar
mechanisms may be involved in structuring stellar systems on a wide range
of scales. ...
Gingerich, Owen, "The Scale of the Universe: A Curtain Raiser in Four Acts
and Four Morals,"
PASP, 108, 1068-1072 (1996)
We normally think of Shapley's pioneering work at Mt. Wilson Observatory
as delineating the scale of the Milky Way without any quantitative concern
for the spiral nebula. It may therefore be a surprise to learn that in
1917 he proposed in the PASP, on the basis of observed novae, that
M31, the Andromeda nebula, was at least a million light years away
1917). What happened? Why did he retreat so quickly from his
published opinion? [Details are summarized.] [p. 1070]
Is there a moral here? Shapley did not have a clue then about
supernovae, interstellar absorption, or the distinction between Population
I and Population II cepheids, . . . The moral, with
its warning to today's debaters, I draw from Shakespeare:
There are more things in heaven and earth than are dreamt of in your
In the annals of modern science, the publication date, or the date of
presentation to some august body, is generally used to set priorities and
time tables for significant discoveries. . . . Consequently, we
tend to date Hubble's great discovery of cepheids in M31 to 1925, to his
formal announcement, in absentia, in Washington at the joint meeting of
the AAS and the AAAS on New Year's Day of that year.
As Allan Sandage (1961, pp. 4-5) put it in the introduction to The Hubble
Atlas of Galaxies,
"The announcement of Hubble's discovery was dramatic... When Hubble's paper
had been read, the entire Society knew that the [great] debate had come to
an end, that the island-universe concept of the distribution of matter in
space had been proved, and that an era of enlightenment in cosmology had
begun." . . .
Richard Berendzen and Michael Hoskins (1971) have written, any account
of an instantaneous, overnight resolution of a controversy arouses the
suspicion of the historian.
. . . [A summary of Hubble's earlier disclosures to his colleagues, and
their reactions to the news is given.]
Sulentic, Jack, and Smith, Brett, "A Fresh Look at Discordant Redshift
Galaxies in Compact Groups,"
Astrophys. Space Sci., 244,23-28 (1996)
Astronomy in Sweden 1860-1940. Uppsala Newsletter: History of
Science, 26, (1997).
Offers a commentary on Lundmark's work on spiral nebulae in Sweden.
(Comments are in the fourth and third paragraphs from the end.)
Arp, Halton C., Seeing Red: Redshifts, Cosmology and Academic Science,
Apeiron, Montreal (1998).
Chandar, R., Bianchi, L., Ford, H.C., Sarajedini, A., "Kinematics of Star
Clusters in M33: Distinct Populations," ApJ, 564, 712-735
AAS online publication
We present velocity measurements for 107 star clusters in the nearby,
low-luminosity spiral galaxy M33...The young clusters
have a maximum circular velocity of 87 ± 11 km sec-1.
[Added 07 Feb 2007.] [Smith (1970) found velocities ranging from 19 to 34
km sec-1 in H II regions in M101 and M33.]
Duerbeck, H.W., "Extragalactic Research in Europe and the United States
in the Early 20th Century,"
AN, 323, 534-537 (2002)
While the theoretical foundations of modern relativistic cosmology were
laid, to a large extent, by European researchers like Einstein, de Sitter,
Friedmann, Lemaître, and others, observational cosmology was (and to a
large extent, still is) dominated by US astronomers, working at Lick and
Mt. Wilson observatories. From today's viewpoint, Hubble appears to dwarf
all his - national and international - peers. However, Keeler and Curtis,
Fath and Slipher carried out pioneering work in the US, as did Wolf, Wirtz,
Lundmark, de Sitter in Europe, . . . European extragalactic research
during the early 20th century is outlined and compared with studies in the
United States. Reasons for the small impact of European research are a
mixture of deliberate and accidental neglect and suppression, as well as
the lack of technical and organizational infrastructure, which was
especially noticeable after World War I. [Abstract © 2002:
Brunthaler, A., Reid, M.J., Falcke, H., Greenhill, L.J., Henkel, C.,
The Geometric Distance and Proper Motion of the Triangulum Galaxy (M33),
Science, 307, 1440-1443 (2005)
Sciencemag Abstract - Article
These researchers seem to be working under the assumption that the internal
motions in M33 behave more or less homogeneously (similar to that expected
for a semi-rigid disk) and that rotational velocity, as a function of
distance from the center of the disk, can be approximated by a smooth
mathematical function. According to van Maanen, the motions could more
likely be represented by spiraling river-like streams with regions
of stagnation between the spiral elements. Brunthaler's team studied
maser regions which do not coorespond to any regions that van Maanen
evaluated astrometrically. The team did measure internal motions
but these were on the order of 1000 times less than those reported by van
Maanen and they were in the opposite direction.
See the author's article
Messier 33 Internal Motions (under construction) which compares recent
findings versus those of van Mannen. [2005 entries were added on
07 Feb 2007.]
Shin-Yi Lin, Nagayoshi Ohashi, Jeremy Lim, Paul T.P. Ho, Misato Fukagawa
and Motohida Tamura, "Possible Molecular Spiral Arms in the Protoplanetary
Disk of AB Aurigae," ApJ, 645,
1297-1304 (2006) -
Circumstellar dust disk (size 144 x 100 AU) exhibits a complex spiral arms
structure. Rotating gas disk (530 x 330 AU) shows maximum
rotational velocity of 2.8 km/sec at 450 AU. (Rotation period would be
on the order of 760 years.) [Added 26 Dec 2007.]
Evidence that Supported Doubts that Spiral Nebulae are Separate Galaxies -
Center for History of Physics - AIP.
The Space Motion of Leo I: Hubble Space
Telescope Proper Motion and Implied Orbit arXiv.org>astro-ph> arXiv:1210.6039
[Added 08 Dec 2012]