Halley's Comet Research Articles

Nonlinear oscillations of dust‐acoustic waves in non‐Maxwellian dusty plasma under the gravitational force effect

AbstractIn this paper, the role of dust grain's gravitational force on the nonlinear dust‐acoustic oscillations in non‐Maxwellian dusty plasma is analyzed. It is shown that increasing the number of non‐thermal ions causes the diminution of the electrostatic potential's amplitude and a reduction in the number of oscillations introduced by the gravitational force. We have also found that reducing the size of the dust grain induces qualitatively the same effects as an increase in the number of non‐thermal ions and when the gravitational force is considered, the electric charge exhibits oscillatory profile and becomes less negative far away from the origin. This result may be interesting in the study of astrophysical plasmas where the electromagnetic force is smaller than the gravitational one such as in the Halley Comet.

Dynamics and head-on collisions of multidimensional dust acoustic shock waves in a self-gravitating magnetized electron-depleted dusty plasma

The dynamics and collisions of dust acoustic (DA) shock excitations traveling in opposite directions are theoretically investigated in a three-dimensional self-gravitating magnetized electron-depleted dusty plasma whose ingredients are extremely warm positively and negatively charged massive dust grains as well as ions that follow the q-nonextensive distribution. A linear analysis and the extended Poincare–Lighthill–Kuo method are used to derive the dispersion relation, the two-sided Korteweg–de Vries Burgers equations, and the phase shift that occurs due to the wave interaction. It is found that gravitation introduces Jeans-like instability, reduces the wave damping rate, decays the aperiodic oscillatory structure of DA excitations, and strongly affects the amplitude, steepness, and occurrence of monotonic compressive and rarefactive shocks. Numerical simulations also highlighted the stabilizing role of the magnetic field and the singularities of the collision process of monotonic shock fronts as well as the undeniable influence of viscosity, ion nonextensivity, and obliqueness between counter-traveling waves on the phase shift and collision profiles. The present results may be useful to better understand interactions of dust acoustic shock waves in the laboratory and astrophysical scenarios, such as dust clouds in the galactic disk, photo-association regions separating H II regions from dense molecular clouds, Saturn's planetary ring, and Halley Comet.

Referencias al cometa Halley desde el observatorio de Cádiz

This paper presents the history of the observations of Halley's comet, in its first scheduled appearance, which were made from the Observatory of Cádiz. A history that links Cadiz with important names: Edmund Halley, who went to Isaac Newton to check the comet's orbit; Jorge Juan and the creation of the Cadiz Observatory which his friend Luis Godin would direct; important astronomers such as Joseph-Nicolas Delisle, who talked to Halley in London and was interested in his predictions, and his disciple the astronomer Charles Messier, who was nicknamed the comet hunter, due to the number of comets he described. Godin, who was himself a fellow astronomy student of Delisle, tracked Halley's comet from the Cadiz observatory, and it is recorded that these observations were taken and sent to Delisle. At a time when data collection was manual, as was the copying of the data and the corresponding annotations; and at a time when the transfer of information was not like e-mails, but was done by horse-drawn carriage, the guarantee that this information reached so many kilometres away could only be given in a later publication. That ratification is the one presented in this article, which completes the link between the Observatory of Cádiz and Halley's comet.

Analytical images of Kepler's equation solutions and their applications

The simple fast-converging analytical calculations algorithms for eccentric anomaly are proposed for an arbitrary eccentricity 0<e≤1. The kinematic characteristics of Halley's comet are calculated as the function of time. Mass of Galaxy + NGC 224 system using the model of elliptical relative motion is also estimated.

Nobel Prize Level Scientific Discoveries of a Heir of Zaporizhian Cossacks

In this work, three fundamental discoveries of the Ukraine-born Prof. George A. Gamow are presented from a single scientific and methodological point of view. Each of them is truly worth of the Nobel Prize – the most prestigious recognition of achievements of a scientist.
 We trace the emergence of G. Gamow as one of the most outstanding scientists of the twentieth century – encyclopaedist, theoretical physicist by heart, astrophysicist and biophysicist, talented and brilliant popularizer of science, whose works are readable in one go, as well as the author of unforgettable pranks and jokes.
 
 Gamow was a Fellow of the Danish Royal Academy of Sciences, the American Academy of Arts and Sciences, the International Astronomical Union, the American Physical Society, an honorary doctor of countless universities. Although his name is little known in Ukraine, the history of science would be incomplete without him.
 
 From an early age G. Gamow has shown a great interest in scientific research, using a microscope to look for erythrocytes and a telescope to observe the Halley comet. He graduated from the Faculty of Physics and Mathematics of Leningrad State University, where he followed classes of Professor O. Friedman, founder of the evolutionary cosmology. He has undergone training at the University of Goettingen, the center of theoretical physics at the time, worked for Nobel Prize winners Professors E. Rutherford and N. Bohr. At the age of 28, G. Gamow, by the recommendation of academician V. Vernadskyi, became the member of the Academy of Sciences of USSR, the youngest member in the entire history of its existence.
 Throughout his life, G. Gamow was interested in the fundamental scientific problems and made numerous world-class discoveries that are written by golden letters in the treasury of the human civilization. He has found explanation to the E. Rutherford’s experiments with alpha particles (tunnelling effect); introduced the empirical formula of Geiger – Nettoll, connecting the energy of alpha particles to the half-life of radioactive nuclei. G. Gamow is one of the pioneers of the liquid-drop model of a nucleus, and the application of nuclear physics to the evolution of stars. He proposed a fantastic hypothesis about the early universe, suggesting it being not only super dense but also very hot. He also built the Big Bang theory, which led to the existence of relic radiation (space microwave background) with the characteristic temperature of 5–7 degrees above the absolute zero, detected by methods of radio astronomy. He proposed a triplet model of the genetic code - the alphabet of life with three-letter words, experimentally proven by X-ray structural studies of DNA and empirically established rules of E. Chargaff. These discoveries have greatly contributed not only to the development of the modern science, but to the industrial and economic expansion of humanity.

Solitary and shocklike wave solutions for the Gardner equation in dusty plasmas

The propagation of dust ion acoustic waves (DIAWs) for two-temperature ions with isothermal electrons in dusty plasmas has been investigated. Using the reductive perturbation method, the Gardner equation is derived. Many analytical solutions have been presented for small but finite amplitude acoustic waves, e.g. solitary and shocklike waves. The effects of many parameters on the feature of the shocklike waves have been studied for the dusty plasma system. The results of this study could be helpful for understanding the existence of nonlinear potential structures those are observed in various cosmic dust-laden plasmas, such as Saturn's E-ring, noctilucent clouds, Halley's comet and interstellar molecular clouds.

THÉORIE DES COMÈTES ET OBSERVATIONS INÉDITES EN OCCIDENT MUSULMAN

AbstractIn this paper, we present the Aristotelian theory of comets, which is well known in the Muslim West through the commentaries of Ibn Rušd and Ibn Bāǧǧa. This aspect is covered three centuries later in an unknown manuscript attributed to the famous mathematician Ibn Ġāzī al-Miknāsī (1437-1513), and this text is not present in the known list of his works. The author devotes a part of his manuscript to the comet astrology following Ptolemy, and introduces a critical position of Iḫwān al-Ṣafā’, characterized by the rejection of the sidereal comets idea. We are also interested in comet classifications given by Ibn Ġāzī and another author ‘Alī al-Antākī. We found that the content of the De cometis of pseudo-Ptolemy is analogous with the text of Ibn Ġāzī, and almost identical to the text of al-Antākī. Then, we are interested in observations of comets from the 9th to the end of the 19th century in North Africa and in Islamic Spain (Andalusia), recorded in some Arabic manuscripts on astronomy and history, which have never been the subject of an extensive study. The studied observations are: the two comets X/975 P1 and X/998 D1 reported by an anonymous author of the 15th century, the X/1381 V1 comet reported by Ibn al-Qāḍī (1553-1616), the passage of Halley's comet in 1456 reported by Muḥammad al-Zarkašī (1434-1525), the C/1743 X1 comet observed by ‘Abd al-Razzāq ibn Ḥamadūš (1695-1785), which confirm its fan structure, the two observations of Ibn ‘Alī al-Šrīf al-Šalāṭī of the D/1770 L1, and especially the C/1769 P1 comet. The graphic representation of this latter comet is unprecedented in the Muslim West.

Eponyms in science terms (Epistemological aspect)

The paper is devoted to eponyms used in scientific discourse. The concept of the eponym is borrowed from linguistic research. The term is understood from epistemological standpoint. It is stated that eponyms realize two functions in the language of science – cognitive and communicative. It is also stressed that to some extend eponyms connect two worlds – the world of ideas and the world of people, or, more specifically, the world of abstract concepts and the world of scientists, who study these abstract concepts. Historical examples (cases) demonstrating some features of functioning eponyms are given and discussed. The main historical example for the study is the history of discovering Lorentz’s transformations, which had a significant impact on forming the theory of special relativity. In addition, the paper gives the analysis of some other examples, in particular, related to such terms as Halley's comet, L'Hospital rule, Russell's paradox. It is noted that the fact of discovering some scientific object by one or another scientist in general is not the only reason for forming an eponym containing the name of this scientist. The formation of eponyms is influenced by many other factors, including social and political ones.

Dynamical evolution and end states of active and inactive Centaurs

We numerically study the dynamical evolution of observed samples of active and inactive Centaurs and clones that reach the Jupiter-Saturn region. Our aim is to compare the evolution between active and inactive Centaurs, their end states and their transfer to Jupiter family comets and Halley-type comets. We find that the median lifetime of inactive Centaurs is about twice longer than that for active Centaurs, suggesting that activity is related to the residence time in the region. This view is strengthened by the observation that high-inclination and retrograde Centaurs (Tisserand parameters with respect to Jupiter TJ<2) which have the longest median dynamical lifetime (=1.37×106 yr) are all inactive. We also find that the perihelion distances of some active, comet-like Centaurs have experienced drastic drops of a few au in the recent past (∼102−103 yr), while such drops are not found among inactive Centaurs. Inactive Centaurs with TJ≲2.5 usually evolve to Halley-type comets, whereas inactive Centaurs with TJ≳2.5 and active Centaurs (that also have TJ≳2.5) evolve almost always to Jupiter family comets and very seldom to Halley type comets. Inactive Centaurs are also more prone to end up as sungrazers, and both inactive and active Centaurs transit through different mean motion resonances (generally with Jupiter) during their evolution.

Likely Transiting Exocomets Detected By Kepler.

We present the first good evidence for exocomet transits of a host star in continuum light in data from the Kepler mission. The Kepler star in question, KIC 3542116, is of spectral type F2V and is quite bright at Kp = 10. The transits have a distinct asymmetric shape with a steeper ingress and slower egress that can be ascribed to objects with a trailing dust tail passing over the stellar disk. There are three deeper transits with depths of ≃ 0.1% that last for about a day, and three that are several times more shallow and of shorter duration. The transits were found via an exhaustive visual search of the entire Kepler photometric data set, which we describe in some detail. We review the methods we use to validate the Kepler data showing the comet transits, and rule out instrumental artefacts as sources of the signals. We fit the transits with a simple dust-tail model, and find that a transverse comet speed of ∼35-50 km s-1 and a minimum amount of dust present in the tail of ∼ 1016 g are required to explain the larger transits. For a dust replenishment time of ∼10 days, and a comet lifetime of only ∼300 days, this implies a total cometary mass of ≳ 3 × 1017 g, or about the mass of Halley's comet. We also discuss the number of comets and orbital geometry that would be necessary to explain the six transits detected over the four years of Kepler prime-field observations. Finally, we also report the discovery of a single comet-shaped transit in KIC 11084727 with very similar transit and host-star properties.

Records of Sighting of Halley's Comet in the 1531 Apparition and an Eclipse in Guru Nanak's References

Two celestial occurrences find place in the incidents related to the great poet - saint Guru Nanak (1469-1539 CE), founder of Sikhism, or in his teachings. The first one referred to as lamma tara (long star) figures in a hymn in the Sri Guru Granth Sahib and the other is a solar eclipse that occurred while Guru Nanak was visiting Kurukshetra. I conclude that the long star must be Halley's Comet in its apparition in 1531. This is significant considering that the record of sighting of a comet in an Indian scripture has so far not been identified. Further, among the many eclipses occurring during the relevant period of 1498-1521, that of 13 January 1507 is the most probable one. The eclipse is historical in the sense that it is the first observational record to be depicted in an Indian mural.

Dissipative dust-acoustic shock waves in a varying charge electronegative magnetized dusty plasma with trapped electrons

The combined effects of an oblique magnetic field and electron trapping on dissipative dust-acoustic waves are examined in varying charge electronegative dusty plasmas with application to the Halley Comet plasma (∼104 km from the nucleus). A weakly nonlinear analysis is carried out to derive a modified Korteweg-de Vries-Burger-like equation. Making use of the equilibrium current balance equation, the physically admissible values of the electron trapping parameter are first constrained. We then show that the Burger dissipative term is solely due to the dust charge variation process. It is found that an increase of the magnetic field obliqueness or a decrease of its magnitude renders the shock structure more dispersive.

MIENTRAS TANTO EN LA TIERRA: IRONÍA Y SIMULACRO EN ¡ARRE! HALLEY ¡ARRE!, DE ELVIRA HERNÁNDEZ

From the media manipulation prompted by the Chilean dictatorship during the months prior to the sighting of Halley's comet, this article reads the irony present in the poetry collection of Elvira Hernandez‟s !Arre! Halley! Arre! (1986) as a strategy that aims at not only confirming the identity of a fractured community, but also at criticizing the dictatorial intention to assimilate the success of emerging neoliberal policies with “unique and unrepeatable” astronomical sightings.

Korean Historical Records on Halley's Comet Revisited

In this paper, we report the analysis of Korean historical records on the periodic Halley’s comet according to the period (i.e., the Three Kingdoms, Goryeo Dynasty, and Joseon Dynasty) using various sources such as the Samguksagi (The History of the Three Kingdoms), Goryeosa (The History of the Goryeo Dynasty), and Joseonwangjosillok (The Annals of the Joseon Dynasty). With regards to the apparition time of the comet for each return, we referred to the works of Kronk. For the Three Kingdoms period, we could not find any record relevant to Halley’s comet from the Samguksagi. Furthermore, we examined the suggestion that the phenomenon of “two Suns” which appeared on April 1, 760 (in a luni-solar calendar), as recorded in the Samgukyusa (The Legends and History of the Three Kingdoms), indicates an instance of the the daytime appearance of Halley’s comet. In contrast with the Three Kingdoms period, we found that all returns of Halley’s comet are recorded during the Goryeo Dynasty, although others have questioned some accounts. We also found that the appearance of Halley’s comet in 1145 is mentioned in a spirit-path stele made in 1178. For the Joseon Dynasty period, we found that all apparitions of the comet are recorded, as with the Goryeo Dynasty, except for the return of 1910, at which time the former dynasty had fallen. In conclusion, we think that this study will be helpful for understanding Korean historical accounts on Halley’s comet.

Decoded Codes of Comet Halley

The subject of the research we are discussing in this text is the cyber-information access to the research of the harmonic dynamics of comet Halley. Cosmic mechanics has been always a perfect example of the regular, deterministic, motion which allows a prediction to a fairly high accuracy. The analysis of these data allowed us to conclude that the motion of Halley's comet is harmonious.

Decoded Codes of Comet Halley

The subject of the research we are discussing in this text is the cyber-information access to the research of the harmonic dynamics of comet Halley. Cosmic mechanics has been always a perfect example of the regular, deterministic, motion which allows a prediction to a fairly high accuracy. The analysis of these data allowed us to conclude that the motion of Halley's comet is harmonious.

The Fragment of Al-Kindī's Lost Treatise on Observations of Halley's Comet in A.D. 837

1. IntroductionIn the first half of the ninth century, a generation of Muslim scholars emerged under the support of the Abbasid Caliphs in Baghdad, among whom the great polymath al-Kindl stands tall. There is an astrological work written by him (on the duration of the reign of the Arabs), in which he mentions an uprising in a.d. 866, and so he must have died later than that date,' most likely around 870. He started his work under al-Ma'mun (reigned 813-833) but served mostly under the caliphate of al-MuTasim (reigned 833-842), during which his career reached to its peak.2 Since he was still alive in the late 860s and most likely an active scholar around 830, he probably was bom about 800.3The most important feature of al-Kindl's wider historical context is that he worked during the translation movement that was encouraged by the Abbasid Caliphs.4 Al-Kindl's scientific works had a two-fold influence on the development of the sciences in the early stage of the Islamic period: they expounded the newly translated Greek texts, and then promoted them by discussing their authenticity.Ibn al-Nadlmin his al-fihrist devotes several sections to al-Kindl's scientific works, such as arithmetic, geometry, music, astronomy, meteorology, and spherics.5 The list of Al-KindT's meteorological works includes two lost treatises, entitled His treatise on what was observed of the great atmospheric phenomenon in 222 a.h. (Kitab risalatih fima rasada min al-athar al-cazim fisanat ithnatayn wa cishnn wa mi 'atayn li- 'l-hijra) and His treatise on a comet that appeared and [al-Kindl] observed it for some days until it faded out (Kitab risalatih fi kawkab alladhi zahara wa rasadahu ayyaman hatta idmahalla).6The title of the first treatise indicates that it concerns al-Kindl's observation of an 'atmospheric' phenomenon that appeared in 222 a.h./a.d. 837 and which we can probably identify as a comet.7 Rada supposes that this would have been al-Kindl's treatise on observations of Halley's Comet which appeared in that year.8 In this article, I will demonstrate that this conjecture is definitely correct. Moreover, it is quite possible that the second treatise was associated with the same topic.9Recently, I came across a treatise entitled Nayazik,'0 during my research into a collection of manuscript images from Princeton University Library. This treatise is said to be an Arabic commentary on Aristotle's lost treatise on comets, written by Hunayn ibn Ishaq al-clbadl from the ninth century.12 Hunayn, who was contemporary to al-Kindl, translated numerous Greek scientific texts into Arabic.13 However, Hunayn's commentary on Aristotle's treatise has not come down directly to us in the original form although a recension (with later additions) is currently at our disposal. Much of the text concerns the implications of for judicial astrology.14 The recension was certainly written after 299 a.h./a.d. 912 (see below), and as a whole it still awaits a detailed study. However, there is a passage in it dealing with al-Kindfs observational report of a comet that appeared in 222 a.h7a.d. 837.15 This passage (with some hiatuses) also appears in another treatise regarding prognosis of entitled 'The gift of sages on description of the prognosis of comets (Tuhfat al-albab fibayan hukm al-adhnab) written by al-Maqdisiwho lived c. 1675, probably in Cairo.16 Further research shows that the report is very likely a summary or a fragment of al-Kindfs lost treatise on observations of Halley's Comet in a.d. 837 (see below).17 Only one other description of Halley's Comet's appearance in 837 has previously been known from Islamic sources, to be found in the voluminous History of Ibn al-Athlr; this has been examined by Rada and Cook.18The return of Halley's Comet in a.d. 837 marks its closest known approach to Earth and has been among the closest ones for any comet ever seen in history. It was also the most thoroughly documented account of Halley's Comet during the first millennium. …

Planetary perturbations for Oort cloud comets: III. Evolution of the cloud and production of centaurs and Halley type comets

We present Monte Carlo simulations of the dynamical history of the Oort cloud, where in addition to the main external perturbers (Galactic tides and stellar encounters) we include, as done in a companion paper (Fouchard, M., Rickman, H., Froeschlé, Ch., Valsecchi, G.B. [2013b]. Icarus, in press), the planetary perturbations experienced each time the comets penetrate to within 50AU of the Sun. Each simulation involves an initial sample of four million comets and extends over a maximum of 5Gyr. For better understanding of the outcomes, we supplement the full dynamical model by others, where one or more of the effects are left out. In the companion paper we studied in detail how observable comets are injected from the Oort cloud, when account is taken of the planetary perturbations. In the present paper we concentrate on how the cloud may evolve in the long term and also on the production of decoupled comets, which evolve into semi-major axes less than 1000AU. Concerning the long-term evolution, we find that the largest stellar perturbations that may statistically be expected during the age of the Solar System induce a large scale migration of comets within the cloud. Thus, comets leave the inner parts, but the losses from the outer parts are even larger, so at the end of our simulations the Oort cloud is more centrally condensed than at the beginning. The decoupled comets, which form a source of centaurs and Halley type comets (roughly in the proportions of 70% and 30%, respectively), are mainly produced by planetary perturbations, Jupiter and Saturn being the most efficient. This effect is dependent on synergies with the Galactic tide and stellar encounters, bringing the perihelia of Oort cloud comets into the planetary region. The star-planet synergy has a large contribution due to the strong encounters that produce major comet showers. However, outside these showers a large majority of decouplings may be attributed to the tide-planet synergy.

태양돛 우주선의 궤도천이 기법 연구

태양돛은 태양복사압을 이용하여 연료소모 없이 우주선에 지속적인 추력을 제공하는 방식으로, 심우주 임무나 지속적인 궤도기동이 필요한 임무에 적합하다. 본 논문에서는 태양돛의 기본 원리를 소개하고 태양중심, 행성중심 궤도에서의 국소최적제어 기법을 연구하였다. 각각의 최적제어 기법에 대한 시뮬레이션을 수행하였다. 핼리혜성 랑데부 궤적을 생성하였으며, 여러 가지 행성탈출 기법을 비교하였다. Solar sail propulsion uses solar radiation pressure to propel spacecraft without propellant, and it is useful for deep-space missions and continuos orbit maneuver missions. After a brief introduction of solar sail dynamics, locally optimal trajectories in Sun-centered and Earth-centered orbits are analyzed. Numerical simulations for the optimal trajectories are performed. Trajectory for the rendezvous with Halley comet is generated, and different planet escape methods are compared.

Dust-acoustic shock waves in a charge varying electronegative magnetized dusty plasma with nonthermal ions: Application to Halley Comet plasma

Weak dust-acoustic waves (DAWs) are addressed in a nonthermal charge varying electronegative magnetized dusty plasmas with application to the Halley Comet. A weakly nonlinear analysis is carried out to derive a Korteweg-de Vries-Burger equation. The positive ion nonthermality, the obliqueness, and magnitude of the magnetic field are found to modify the dispersive and dissipative properties of the DA shock structure. Our results may aid to explain and interpret the nonlinear oscillations that may occur in the Halley Comet Plasma.