scholarly journals Note on the intensity decrement in the balmer series

1919 ◽  
Vol 96 (675) ◽  
pp. 112-119 ◽  
Keyword(s):  
Hydrogen Atom ◽  
Low Pressure ◽  
Quantitative Comparison ◽  
The Sun ◽  
Previous Knowledge ◽  
Balmer Series ◽  
Celestial Bodies ◽  
Theoretical Considerations

One of the most remarkable examples of spectrum lines which are common in celestial bodies, but which have hitherto resisted all attempts to reproduce them in the laboratory, is afforded by the higher members of the Balmer series of hydrogen. As many as 29 members of this series have been observed by Dyson and Evershed in the chromosphere of the sun, but the greatest number observed in the laboratory by Ames and by Cornu was only 13, and the last of these were of such a character that it would hardly have been possible to record them without a previous knowledge of their localisation. In many respects the failure to reproduce in the laboratory lines whose chemical origin is known, and which are so prominent in celestial spectra, is even more conspicuous than in the case of the nebular and coronal lines, which cannot yet be referred to any atom known in chemistry, and which may be due to substances which do not, or perhaps cannot, exist under terrestrial conditions. A further interest has been added to the problem by the important theoretical wrork of Bohr, whose theory of the production of the Balmer series requires that the space occupied by a hydrogen atom, in the process of emitting lines of the higher members of the Balmer series, is such that these radiations cannot be expected to be visible except under conditions of extremely low pressure. Bohr has pointed out that this view is consistent with the appearance of the lines in celestial spectra, and our inability to produce them under the conditions ordinarily obtaining in the laboratory. Liveing and Dewar have found that in a mixture of the more volatile gases of the atmosphere, consisting mainly of neon and helium and containing hydrogen, the Balmer series could be traced as far as the ninth member; and in a recent investigation we have made a quantitative comparison of the distribution of intensity in the earlier members of the series in hydrogen, and in neon containing hydrogen as an impurity. This observation of Liveing and Dewar is remarkable, but we have recently found that similar results can be obtained in helium containing hydrogen at pressures so great that, on the theoretical considerations above referred to, it would seem impossible that these radiations should be detected.

scholarly journals III. On the nature and construction of the sun and fixed stars

1795 ◽  
Vol 85 ◽  
pp. 46-72 ◽  
Keyword(s):  
Central Body ◽  
Planetary System ◽  
Considerable Progress ◽  
The Sun ◽  
Great Satisfaction ◽  
The Earth ◽  
The World ◽  
Celestial Bodies ◽  
The Universe ◽  
Made In

Among the celestial bodies the sun is certainly the first which should attract our notice. It is a fountain of light that illuminates the world! it is the cause of that heat which main­tains the productive power of nature, and makes the earth a fit habitation for man! it is the central body of the planetary system; and what renders a knowledge of its nature still more interesting to us is, that the numberless stars which compose the universe, appear, by the strictest analogy, to be similar bodies. Their innate light is so intense, that it reaches the eye of the observer from the remotest regions of space, and forcibly claims his notice. Now, if we are convinced that an inquiry into the nature and properties of the sun is highly worthy of our notice, we may also with great satisfaction reflect on the considerable progress that has already been made in our knowledge of this eminent body. It would require a long detail to enumerate all the various discoveries which have been made on this subject; I shall, therefore, content myself with giving only the most capital of them.

scholarly journals Structure of the Balmer jump

2018 ◽  
Vol 613 ◽  
pp. A55
Author(s):  
F. Calvo ◽  
L. Belluzzi ◽  
O. Steiner
Keyword(s):  
Hydrogen Atom ◽  
Absorption Coefficient ◽  
Total Cross Section ◽  
Analytical Model ◽  
Cross Section ◽  
Quantum Structure ◽  
Balmer Series ◽  
Polarization Phenomena ◽  
Definition Of ◽  
Rapid Drop

Context.The spectrum of the hydrogen atom was explained by Bohr more than one century ago. We revisit here some of the aspects of the underlying quantum structure, with a modern formalism, focusing on the limit of the Balmer series.Aims.We investigate the behaviour of the absorption coefficient of the isolated hydrogen atom in the neighbourhood of the Balmer limit.Methods.We analytically computed the total cross-section arising from bound-bound and bound-free transitions in the isolated hydrogen atom at the Balmer limit, and established a simplified semi-analytical model for the surroundings of that limit. We worked within the framework of the formalism of Landi Degl’Innocenti & Landolfi (2004, Astrophys. Space Sci. Lib., 307), which permits an almost straight-forward generalization of our results to other atoms and molecules, and which is perfectly suitable for including polarization phenomena in the problem.Results.We analytically show that there is no discontinuity at the Balmer limit, even though the concept of a “Balmer jump” is still meaningful. Furthermore, we give a possible definition of the location of the Balmer jump, and we check that this location is dependent on the broadening mechanisms. At the Balmer limit, we compute the cross-section in a fully analytical way.Conclusions.The Balmer jump is produced by a rapid drop of the total Balmer cross-section, yet this variation is smooth and continuous when both bound-bound and bound-free processes are taken into account, and its shape and location is dependent on the broadening mechanisms.

scholarly journals Peranan Simbol Benda-Benda Langit Dalam Perkembangan Religi Masyarakat Di Indonesia

1999 ◽  
Vol 19 (1) ◽  
pp. 66-77
Author(s):  
Nfn. Hartatik
Keyword(s):  
The Sun ◽  
Global Function ◽  
Celestial Bodies ◽  
Ethnographic Data ◽  
Rock Paintings

Celestial objects are always present in the form of symbols depicted in rock paintings, nekara, megalithic concepts, symbols of royal triumph and in conventional myths as can be found in the ethnographic data of several tribes in Indonesia. In general, celestial bodies, especially the sun, moon and stars are symbols whose rays are considered to be the source of life, the light of truth and justice that are expected to be able to illuminate mankind. In their development, the role of celestial bodies has shifted from a religious function to a global function that tends to be profane, which includes social and political functions. However, the presence of a symbol representing an infinite character always exists as a generator of feelings of togetherness and a deeper attachment than just a verbal formulation.

scholarly journals The stark effect of the fine-structure of hydrogen

1928 ◽  
Vol 119 (782) ◽  
pp. 313-334 ◽  
Keyword(s):  
Fine Structure ◽  
Hydrogen Atom ◽  
Electric Field ◽  
Quantum Dynamics ◽  
Stark Effect ◽  
Energy Levels ◽  
Structure Theory ◽  
Weak Electric Field ◽  
Classical Dynamics ◽  
Balmer Series

One of the earliest successes of classical quantum dynamics in a field where ordinary methods had proved inadequate was the solution, by Schwarzschild and Epstein, of the problem of the hydrogen atom in an electric field. It was shown by them that under the influence of the electric field each of the energy levels in which the unperturbed atom can exist on Bohr’s original theory breaks up into a number of equidistant levels whose separation is proportional to the strength of the field. Consequently, each of the Balmer lines splits into a number of components with separations which are integral multiples of the smallest separation. The substitution of the dynamics of special relativity for classical dynamics in the problem of the unperturbed hydrogen atom led Sommerfeld to his well-known theory of the fine-structure of the levels; thus, in the absence of external fields, the state n = 1 ( n = 2 in the old notation) is found to consist of two levels very close together, and n = 2 of three, so that the line H α of the Balmer series, which arises from a transition between these states, has six fine-structure components, of which three, however, are found to have zero intensity. The theory of the Stark effect given by Schwarzschild and Epstein is adequate provided that the electric separation is so much larger than the fine-structure separation of the unperturbed levels that the latter may be regarded as single; but in weak fields, when this is no longer so, a supplementary investigation becomes necessary. This was carried out by Kramers, who showed, on the basis of Sommerfeld’s original fine-structure theory, that the first effect of a weak electric field is to split each fine-structure level into several, the separation being in all cases proportional to the square of the field so long as this is small. When the field is so large that the fine-structure is negligible in comparison with the electric separation, the latter becomes proportional to the first power of the field, in agreement with Schwarzschild and Epstein. The behaviour of a line arising from a transition between two quantum states will be similar; each of the fine-structure components will first be split into several, with a separation proportional to the square of the field; as the field increases the separations increase, and the components begin to perturb each other in a way which leads ultimately to the ordinary Stark effect.

scholarly journals The Antikythera Mechanism: The oldest mechanical universe in its scientific milieu

2009 ◽  
Vol 5 (S260) ◽  
pp. 135-148 ◽  
Author(s):  
Xenophon Moussas
Keyword(s):  
Main Part ◽  
Accurate Prediction ◽  
The Other ◽  
Stationary Points ◽  
Analogue Computer ◽  
The Sun ◽  
The Moon ◽  
Celestial Bodies ◽  
Celestial Sphere ◽  
Astronomical Instrument

AbstractIn this review the oldest known advanced astronomical instrument and dedicated analogue computer is presented, in context. The Antikythera Mechanism a mysterious device, assumed to be ahead of its time, probably made around 150 to 100 BCE, has been found in a 1st century BCE shipwreck near the island of Antikythera in a huge ship full of Greek treasures that were on their way to Rome. The Antikythera Mechanism is a clock-like device made of bronze gears, which looks much more advanced than its contemporary technological achievements. It is based on mathematics attributed to the Hipparchus and possibly carries knowledge and tradition that goes back to Archimedes, who according to ancient texts constructed several automata, including astronomical devices, a mechanical planetarium and a celestial sphere. The Antikythera Mechanism probably had a beautiful and expensive box; looking possibly like a very elaborate miniature Greek Temple, perhaps decorated with golden ornaments, of an elegant Hellenistic style, even perhaps with automatic statuettes, ‘daemons’, functioning as pointers that performed some of its operations. Made out of appropriately tailored trains of gears that enable to perform specialised calculations, the mechanism carries concentric scales and pointers, in one side showing the position of the Sun in the ecliptic and the sky, possibly giving the time, hour of the day or night, like a clock. The position of the Moon and its phase is also shown during the month. On the other side of the Mechanism, having probably the size of a box (main part 32×20×6 cm), are two large spiral scales with two pointers showing the time in two different very long calendars, the first one concerning the eclipses, and lasting 18 years 11 days and 8 hours, the Saros period, repeating the solar and lunar eclipses, and enabling their prediction, and the 19 year cycle of Meton, that is the period the Moon reappears in the same place of the sky, with the same phase. An additional four-year dial shows the year of all Greek Festivities, the so-called ‘games’ (Olympic, Pythian, Isthmian etc). Two additional dials give the Exeligmos, the 54 year and 34 day cycle, which provides a more accurate prediction of eclipses. It is possible that the Mechanism was also equipped with a planetary show display, as three of the planets and their motion (stationary points) are mentioned many times in the manual of the instrument, so it was also a planetarium. From the manual we have hints that the mechanism was probably also an observational instrument, as having instructions concerning a viewfinder and possibly how to orient the viewfinder to pass a sunbeam through it, probably measuring the altitude of the Sun. There are fragmented sentences that probably give instructions on how to move the pointers to set the position of the Sun, the Moon and the planets in their initial places in the ecliptic, on a specific day, or how to measure angular distances between two celestial bodies or their coordinates. This mechanism is definitely not the first one of its kind. The fact that it is accompanied with instructions means that the constructor had in its mind to be used by somebody else and one posits that he made at least another similar instrument.

scholarly journals Gudernes rum og menneskenes univers. I de mayatalende lakandoneres verdenssyn

2019 ◽  
Author(s):  
Marie-Odile Marion
Keyword(s):  
Rain Forest ◽  
The Sun ◽  
The Moon ◽  
Symbolic Representations ◽  
Social Forms ◽  
Complex Interactions ◽  
The Social ◽  
Cosmic Space ◽  
Celestial Bodies ◽  
The One

In their mythology, the Lacandons - Indians living in the rain forest of Chiapas, Mexico - conceptualise a tripartite space of heaven, earth, and the underworld. The Lacandons perceive themselves as placed by the gods in the middle of a cosmic space that is created, delimitated and controlled by the two great celestial bodies: the couple of sun and moon. Through a detailed analysis of the symbolic representations of the sun and the gods of wind and rain, it is shown how all the most important features of the Lacandon universe is thought of as the outcome of complex interactions between solar and lunar principles. On the one hand, the workings of the sun (male) and the moon (female) create and recreate the essential qualities of the meteorological, climatic, and ecological spaces that constrain the forms of productive life. On the other hand, the Indians conceptualise the opposition, the alternation, and the complimentarity that characterise the relations between sun and moon as homological to the social forms of Lacandon reproduction. The ambivalent, complex, and multifacetted dialectics of lunar and solar principles reveal that cosmic equilibrium centres round the male-female bipolarity. It is argued that although the male qualities of the sun are considered higher and dominant, it is in faet the mythic image of the moon that metaphorises stability, completeness and totality.

scholarly journals Archaeoastronomical Aspects of the Archaeological Monuments of Siberia

2012 ◽  
Vol 16 (1 and 2) ◽  
pp. 109-117
Author(s):  
Leonid Marsadolov
Keyword(s):  
The Sun ◽  
The Moon ◽  
Astronomical Observations ◽  
The North ◽  
Ancient People ◽  
Celestial Bodies ◽  
Night Sky

The necessity of astronomical observations for nomadic peoples of Eurasia was based on the sacral meaning of time. The celestial bodies, the Sun and the Moon were parts of cult of the Sky. During annual migrations, in particular those where there were no reliable landmarks, nomads navigated with the North Star and the main constellations of the night sky. Remains left by these nomads, including rock pictures, barrows and observation posts are the legacy of a complex, organised system reflecting the relations of ancient people with the cosmos.

scholarly journals The Gravitational Zones of Influence of the Planets Acting on Small Celestial Bodies

1985 ◽  
Vol 85 ◽  
pp. 377-380
Author(s):  
N.Y. Misconi ◽  
E.T. Rusk
Keyword(s):  
Interplanetary Dust ◽  
Gravitational Acceleration ◽  
The Sun ◽  
Orbital Elements ◽  
Gravitational Forces ◽  
Celestial Bodies ◽  
Zone Of Influence ◽  
Definition Of

AbstractTisserand’s definition of the “sphere of action” of a planet is based on the equality of tidal vs. gravitational acceleration ratios of the sun and planet. Öpik and others based their relation on equating the differential solar and planetary forces on a particle. Neither expression was formulated to describe the zone of influence surrounding a planet when considering the small, but significant, long-term perturbative effects of the planets on a particle’s orbital elements. For the purpose of determining these effects on interplanetary dust we derive a zone of influence based on equating the gravitational forces of the sun and planet.

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