II. Computation of the lengths of the waves of light corresponding to the lines in the dispersion spectrum measured by Kirchhoff

1868 ◽  
Vol 158 ◽  
pp. 29-55
Keyword(s):  
Spectral Lines ◽  
The Sun ◽  
Mechanical Theory ◽  
Whole Process ◽  
Physical Research ◽  
Berlin Academy ◽  
Natural Measure ◽  
The One ◽  
The Waves

The greatest and most valuable system of measures which we possess of the lines in the Dispersion Spectrum, produced by the emanation of light from the Sun, by transmission through the Atmosphere, and by the combustion of Metals, is that published by Professor Kirchhoff in the Memoirs of the Berlin Academy for 1861 and 1862. This noble series includes about 1600 lines, taken in uninterrupted succession through the spectrum, beginning a little before Fraunhofer’s line A and ending a little after G. The same apparatus was used throughout, and in the same manner; and the system followed in the whole process was so nearly constant that we may speak of it generally as one consistent series of measures. This work has been made known to English readers by an accurate translation published by Professor Roscoe. The measures thus exhibited depend upon the form of the apparatus, the refractive and dispersive powers of the glass, the nature of the scale employed, and the value of its unit of measure. They are not therefore available for physical research, until they are cleared of the effects of these circumstances of experiment. There can be no hope of our arriving at, or even commencing, any mechanical theory on the formation of the spectral lines, until we have obtained the one natural measure of each, namely the length of the Wave of Light corresponding to each.

The Interpretation of Line Profiles

1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki
Keyword(s):  
Magnetic Fields ◽  
Atomic Physics ◽  
Velocity Fields ◽  
Spectral Lines ◽  
Inhomogeneous Structure ◽  
The Sun ◽  
Line Profiles ◽  
Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

Dombey and Son

2008 ◽  
Author(s):  
Charles Dickens ◽  
Dennis Walder
Keyword(s):  
Family Relationships ◽  
The Sun ◽  
The Novel ◽  
The Earth ◽  
The Future ◽  
Original Illustrations ◽  
The One

Dombey and Son ... Those three words conveyed the one idea of Mr. Dombey's life. The earth was made for Dombey and Son to trade in, and the sun and moon were made to give them light.' The hopes of Mr Dombey for the future of his shipping firm are centred on his delicate son Paul, and Florence, his devoted daughter, is unloved and neglected. When the firm faces ruin, and Dombey's second marriage ends in disaster, only Florence has the strength and humanity to save her father from desolate solitude. This new edition contains Dickens's prefaces, his working plans, and all the original illustrations by ‘Phiz’. The text is that of the definitive Clarendon edition. It has been supplemented by a wide-ranging Introduction, highlighting Dickens's engagement with his times, and the touching exploration of family relationships which give the novel added depth and relevance.

The Tychonic Method for Calculating the Ratio between the Eccentricities of Mars

2021 ◽  
Vol 52 (2) ◽  
pp. 212-234
Author(s):  
Christián C. Carman
Keyword(s):  
The Sun ◽  
Circular Orbits ◽  
The One

In Chapter 16 of Astronomia nova, Kepler describes and applies a method for finding the parameters of what he will call the vicarious hypothesis: a model that still assumes circular orbits and an equant point, but does not assume the bisection of the eccentricity, that is, that the center of the orbit is halfway between the equant point and the Sun. The method allows Kepler to find independently both centers in a very elegant way, but its application is tedious. He confesses that he had to apply it seventy times over a period of 5 years to obtain trustable results. Years earlier, when Kepler arrived to work with Tycho, he found that Tycho and Longomontanus had rejected bisection and somehow had obtained a ratio between eccentricities that, as Kepler himself highlights, happened to be very close to the one Kepler would later find after so much effort. Kepler does not say how Tycho and Longomontanus obtained their parameters and, to the best of my knowledge, there is no single published work that attempts to answer this question. Still, it is a very interesting question to ask how they arrived at values so close to those that took so much pain for Kepler to obtain. Recently, I published a paper describing a method Tycho used for finding Saturn’s parameters. In this paper, I show that by applying this method to the data of Tychonic observations of oppositions, it is possible to arrive at parameters very close to those that we know Tycho found. In this way, I argue that this is the method Tycho applied for obtaining Mars’s parameters. The simplicity of the Tychonic method contrasts with the complexity of Kepler’s.

scholarly journals Gamma Astrometric Measurement Experiment: testing General Relativity with a small mission

2007 ◽  
Vol 3 (S248) ◽  
pp. 290-291 ◽  
Author(s):  
A. Vecchiato ◽  
M. G. Lattanzi ◽  
M. Gai ◽  
R. Morbidelli
Keyword(s):  
General Relativity ◽  
Solar Eclipse ◽  
Galactic Center ◽  
The Sun ◽  
Measurement Experiment ◽  
The One ◽  
First Time ◽  
Bending Of Light

AbstractGAME (Gamma Astrometric Measurement Experiment) is a concept for an experiment whose goal is to measure from space the γ parameter of the Parameterized Post-Newtonian formalism, by means of a satellite orbiting at 1 AU from the Sun and looking as close as possible to its limb. This technique resembles the one used during the solar eclipse of 1919, when Dyson, Eddington and collaborators measured for the first time the gravitational bending of light. Simple estimations suggest that, possibly within the budget of a small mission, one could reach the 10−6level of accuracy with ~106observations of relatively bright stars at about 2° apart from the Sun. Further simulations show that this result could be reached with only 20 days of measurements on stars ofV≤ 17 uniformly distributed. A quick look at real star densities suggests that this result could be greatly improved by observing particularly crowded regions near the galactic center.

scholarly journals The relationship between photometric and spectroscopic oscillation amplitudes from 3D stellar atmosphere simulations

2021 ◽  
Author(s):  
Yixiao Zhou ◽  
Thomas Nordlander ◽  
Luca Casagrande ◽  
Meridith Joyce ◽  
Yaguang Li ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Three Dimensional ◽  
Quantitative Relationship ◽  
Stellar Atmospheres ◽  
Spectral Lines ◽  
Wavelength Shift ◽  
The Sun ◽  
Theoretical Derivation ◽  
Velocity Amplitude ◽  
Good Agreement

Abstract We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, three-dimensional (3D), hydrodynamical numerical simulations of stellar atmospheres. We present a theoretical derivation as proof of concept for our method. We perform realistic spectral line formation calculations to quantify the ratio between luminosity and radial velocity amplitude for two case studies: the Sun and the red giant ε Tau. Luminosity amplitudes are computed based on the bolometric flux predicted by 3D simulations with granulation background modelled the same way as asteroseismic observations. Radial velocity amplitudes are determined from the wavelength shift of synthesized spectral lines with methods closely resembling those used in BiSON and SONG observations. Consequently, the theoretical luminosity to radial velocity amplitude ratios are directly comparable with corresponding observations. For the Sun, we predict theoretical ratios of 21.0 and 23.7 ppm/[m s−1] from BiSON and SONG respectively, in good agreement with observations 19.1 and 21.6 ppm/[m s−1]. For ε Tau, we predict K2 and SONG ratios of 48.4 ppm/[m s−1], again in good agreement with observations 42.2 ppm/[m s−1], and much improved over the result from conventional empirical scaling relations which gives 23.2 ppm/[m s−1]. This study thus opens the path towards a quantitative understanding of solar-like oscillations, via detailed modelling of 3D stellar atmospheres.

Evolution of Comets into Asteroids?

1971 ◽  
Vol 12 ◽  
pp. 413-421 ◽  
Author(s):  
B.G. Marsden
Keyword(s):  
Solar Radiation ◽  
Solar Nebula ◽  
Oort Cloud ◽  
Original Version ◽  
Terrestrial Planets ◽  
Minor Planets ◽  
The Sun ◽  
Physical Difference ◽  
Short Period ◽  
The One

There has long been speculation as to whether comets evolve into asteroidal objects. On the one hand, in the original version of the Oort (1950) hypothesis, the cometary cloud was supposed to have formed initially from the same material that produced the minor planets; and an obvious corollary was that the main physical difference between comets and minor planets would be that the latter had long since lost their icy surfaces on account of persistent exposure to strong solar radiation (Öpik, 1963). However, following a suggestion by Kuiper (1951), it is now quite widely believed that, whereas the terrestrial planets and minor planets condensed in the inner regions of the primordial solar nebula, icy objects such as comets would have formed more naturally in the outer parts, perhaps even beyond the orbit of Neptune (Cameron, 1962; Whipple, 1964a). Furthermore, recent studies of the evolution of the short-period comets indicate that it is not possible to produce the observed orbital distribution from the Oort cloud, even when multiple encounters with Jupiter are considered (Havnes, 1970). We must now seriously entertain the possibility that most of the short-period orbits evolved directly from low-inclination, low-eccentricity orbits with perihelia initially in the region between, say, the orbits of Saturn and Neptune, and that these comets have never been in the traditional cloud at great distances from the Sun.

Transverse dam-break waves

2014 ◽  
Vol 758 ◽  
Author(s):  
S. Karimpour Ghannadi ◽  
Vincent H. Chu
Keyword(s):  
Froude Number ◽  
Flow Rate ◽  
Main Flow ◽  
Dam Break ◽  
The Other ◽  
Water Diversion ◽  
The Family ◽  
The One ◽  
Limiting Case ◽  
The Waves

AbstractNumerical simulations of the transverse dam-break waves (TDWs) produced by the sudden removal of a gate on the side of a waterway are conducted based on the shallow-water equations to find solutions to a family of water-diversion problems. The Froude numbers in the main flow identify the members of the family. The depth and discharge profiles are analysed in terms of Ritter’s similarity variable. For subcritical main flow, the waves are comprised of a supercritical flow expansion followed by a subcritical outflow. For supercritical main flow, on the other hand, the waves are analogous to the Prandtl–Meyer expansion in gas dynamics. The diversion flow rate of two-dimensional TDWs on a flat bed is 55 % greater than the one-dimensional flow rate of Ritter in the limiting case of zero main flow, and approaches the rate of Ritter in the other limit when the value of the Froude number in the main flow approaches infinity. The diversion flow rate over a weir is generally higher than the rate over a flat bed depending on the Froude number of the main flow. These numerical simulation results are consistent with laboratory observations.

scholarly journals Lunar

JOGED ◽  
2017 ◽  
Vol 7 (2) ◽  
Author(s):  
Dewi Sinta Fajawati
Keyword(s):  
Full Moon ◽  
Big Bang ◽  
The Other ◽  
The Sun ◽  
The Moon ◽  
Big Bang Theory ◽  
Essential Idea ◽  
Visual Reaction ◽  
Night Sky ◽  
The One

Bulan merupakan sumber inspiratif dalam penggarapan karya tari ini. Secara ilmu pengetahuan, Bulan adalah benda langit yang disebut satelit, satelit satu-satunya yang dimiliki Bumi dan tercipta secara alami. Banyak teori yang mengatakan tentang terbentuknya Bulan, salah satunya adalah teori Big bang atau dentuman besar. Pada dasarnya Bulan hanyalah sebuah Benda besar berbentuk bulat yang tidak bisa bercahaya, cahaya yang kita lihat pada malam hari merupakan refleksi dari cahaya matahari. Akan tetapi keindahannya memang tidak bisa dipungkiri, karena dia paling bercahaya diantara hamparan langit yang gelap. Cahayanya tidak selalu terang, bahkan tidak selalu bulat, terkadang hanya terlihat setengah atau terlihat seperti sabit..            Penata tari memetaforakan objek bulan yang berada di tempat yang sangat tinggi sebagai sebuah cita-cita yang ingin dicapai. Seringkali lagu anak-anak yang menjadi pengalaman auditif penata tari, menjadikan bulan sebagai objek yang ingin digapai, misal lagu ‘Ambilkan Bulan Bu’. Namun intisari yang akan dipakai dalam penggarapan koregrafinya adalah tentang fase bulan yang tercipta. Bersumber dari rangsang awal melihat bulan atau rangsang visual, penata tari menginterpretasikan fase-fase bulan yang terjadi sebagai fase kehidupan yang dijalani untuk menggapai sebuah cita-cita tersebut.            Koreografi diwujudkan dalam bentuk kelompok dengan membagi dua karate penari. Delapan penari merupakan simbolisasi Bulan, dan satu penari sebagai manusia yang bercita-cita. Dengan bentuk tari dramatik, penyajiannya dibagi menjadi 5 adegan, yaitu Introduksi Big bang, Adegan 1 Moon happen, Adegan 2 Mengejar Impian, Adegan 3 Dancing with Moon, dan Ending ‘Catch Your Dream’. The moon is the essential inspirations of this choreograph. Theoretically, the moon is a sky object which is called as satellite. The one and only naturally created satellite belongs to the planet Earth. There are many theories that explain how the moon was created. One of those theories is Big Bang theory or massive crash. Basically, the moon is just a huge circle thing which is unable to shine its glow. The light that we experience in the evening is the reflection of the sun. However, thebeauty of the moonlight is undeniable as it has the significant light within the darkest night sky. Its light is not always the strongest, even it’s not always circle (full), every so often it is seemed only the half part of it or crescent moon.            The choreographer interpreted the moon that belongs in the highest as the goals that she wants to reach. Most of the time, the children songs (lullaby) that pick the moon as the main object that is desired to be reached, for example the song “Ambilkan Bulan, Bu”. The essential idea that is explored in this choreograph is the creational phase of the moon itself. It was started by way of visual reaction when the choreographer observed the moon, she interpret the moon’s phases as the phases in human’s life which are gone through to reaching their goals. Fall and recovery, passionate, and even sometimes they give it in, are interpreted from the moonlight. The full moon which has the brightest and the most perfect light is likened as the strong spirit. The crescent moon with its soft light is interpreted as low spirit and unconfident.             This in-group-choreograph is separated into two characters with 8 female dancers that are the symbolization of the moon and the other one female dancer symbolizes a human with aspire. With dramatic dance form, this choreograph is presented into five parts, including introduction part of Big Bang, Moon Happen in part one, Chasing Dream is part two, Dancing With The Moon in part three, Catch Your Dream in the ending part.

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