共查询到20条相似文献，搜索用时 31 毫秒
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牛广林 《吉林大学学报(地球科学版)》1987,(3)
本文以太阳系星球的物质状态、形态面貌、体积、物质密度、运动速度、运动方向和角动量等作为根据,研究它们在宇宙空间上的分布特点、相互关系、内在联系以及规律的基础上,提出太阳系(乃至宇宙星球)是在46亿年前,宇宙中一个巨大灼热的星球,在高速度左旋旋转(公转和自转)运动的过程中,从尾部分离出来的物质,经过……恒星、行星和卫星依次波状旋转分离运动产生的。 相似文献
3.
Churkin K. O. Andreev A. O. Nefedyev Yu. A. Petrova N. K. Demina N. Yu. 《Astronomy Reports》2018,62(12):1042-1049
An important area of investigation in astronomy is the relationship between fundamental and dynamical coordinate systems. Valuable material for such studies is provided by photoelectric occultation observations of stars by the Moon, which can provide high precision of detecting rapidly occurring processes and have been carried out over a long time interval. This latter feature is especially important for analyses of the stellar propermotions dynamics. A method has been developed to use photoelectric occultation observations to determine the orientation and rotational parameters of the axes of the coordinate system used for modern star catalogs relative to the coordinate axes of a highly accurate dynamical ephemeris of theMoon. A complete database of photoelectric occultation observations has been created for this purpose, containing data for 57 365 events. The combination of photoelectric occultation observations and other astronomical observations such as lunar laser-ranging data enables the highly accurate determination of parameters of the Moon’s dynamics, such as systematic errors in catalog coordinate systems, including various geodetic reference systems. The parameters of shifts and the rotation of the axes of the Hipparcos Celestial Reference Frame relative to the DE421 dynamical system are obtained. This paper is based on a talk given at the conference “Modern Astrometry 2017,” dedicated to the memory of K.V. Kuimov (Sternberg Astronomical Institute, Moscow State University, October 23–25, 2017).
相似文献4.
行星构造:寻求地球演化的踪迹 总被引：1，自引：0，他引：1
地质构造是记录地球内、外动力地质作用过程的标志.和地球相似,太阳系其他天体上也发育丰富的地质构造.以研究天体表面的地质构造及其动力学机制为目的的"行星构造学"是建立在构造地质学、遥感地质学和地球物理学等学科基础上的一门新兴前沿学科.由于天体的大小、组分和轨道位置不同,表面构造特征及其形成机制各异.对比研究地球和其他天体... 相似文献
5.
Z. M. Malkin 《Astronomy Reports》2010,54(11):1053-1061
VLBI observations carried out by global networks provide the most accurate values of the precession-nutation angles determining
the position of the celestial pole; as a rule, these results become available two to four weeks after the observations. Therefore,
numerous applications, such as satellite navigation systems, operational determination of Universal Time, and space navigation,
use predictions of the coordinates of the celestial pole. In connection with this, the accuracy of predictions of the precession—nutation
angles based on observational data obtained over the last three years is analyzed for the first time, using three empiric
nutation models-namely, those developed at the US Naval Observatory, the Paris Observatory, and the Pulkovo Observatory. This
analysis shows that the last model has the best of accuracy in predicting the coordinates of the celestial pole. The rms error
for a one-month prediction proposed by this model is below 100 microarcsecond. 相似文献
6.
James M.D. Day 《Geology Today》2015,31(1):12-20
The history of the solar system is locked within the planets, asteroids and other objects that orbit the Sun. While remote observations of these celestial bodies are essential for understanding planetary processes, much of the geological and geochemical information regarding solar system heritage comes directly from the study of rocks and other materials originating from them. The diversity of materials available for study from planetary bodies largely comes from meteorites; fragments of rock that fall through Earth's atmosphere after impact‐extraction from their parent planet or asteroid. These extra‐terrestrial objects are fundamental scientific materials, providing information on past conditions within planets, and on their surfaces, and revealing the timing of key events that affected a planet's evolution. Meteorites can be sub‐divided into four main groups: (1) chondrites, which are unmelted and variably metamorphosed ‘cosmic sediments’ composed of particles that made up the early solar nebula; (2) achondrites, which represent predominantly silicate materials from asteroids and planets that have partially to fully melted, from a broadly chondritic initial composition; (3) iron meteorites, which represent Fe‐Ni samples from the cores of asteroids and planetesimals; and (4) stony‐iron meteorites such as pallasites and mesosiderites, which are mixtures of metal and dominantly basaltic materials. Meteorite studies are rapidly expanding our understanding of how the solar system formed and when and how key events such as planetary accretion and differentiation occurred. Together with a burgeoning collection of classified meteorites, these scientific advances herald an unprecedented period of further scientific challenges and discoveries, an exciting prospect for understanding our origins. 相似文献
7.
In ephemeridical astronomy, an important role is played by the kinematic equation relating time and position in the orbit. Since the ephemerides have already been calculated for many hundreds of thousands of celestial bodies moving along more or less known orbits, close to optimal algorithms for solving this equation are required. We consider the case of near-parabolic motion, for which Euler found an elegant form for the kinematic equation, to be insufficiently thoroughly studied. Earlier, we presented a solution of this equation using a series in powers of the small parameter introduced by Euler with timedependent coefficients. In the current study, we find the region of convergence of this series. 相似文献
8.
During the accretion of planets such as Earth, which are formed by collisional accretion of plan-etesimals, the probability
of capture of interplanetary bodies in planetocentric orbits is calculated following the approach of Hills (1973) and the
n-body simulation, using simplectic integration method. The simulation, taking an input mass equal to about 50% of the present
mass of the inner planets, distributed over a large number of planetoids, starting at 4 M y after the formation of solar system,
yielded four inner planets within a period of 30 M y. None of these seed bodies, out of which the planets formed, remained
at this time and almost 40% mass was transferred beyond 100 AU. Based on these calculations, we conclude that ∼ 1.4 times
the mass of the present inner planets was needed to accumulate them. The probability of capture of planetoids in geocentric
orbits is found to be negligible. The result emphasizes the computational difficulty in ’probability of capture’ of planetesimals
around the Earth before the giant impact. This conclusion, however, is in contradiction to the recent observations of asteroids
being frequently captured in transient orbits around the Earth, even when the current population of such interplanetary bodies
is smaller by several orders of magnitude compared to the planetary accumulation era. 相似文献
9.
The fall of a meteorite near the town of Chelyabinsk is considered from the viewpoint of astronomy, and the major witness facts and entry characteristics (including the measured entry velocity and the height of the explosion) are analyzed. The aerodynamic phenomena that accompanied the entry of the meteorite in the atmosphere at an ultrasonic velocity and the origin of a shock wave that induced damage on the Earth’s surface are analyzed. The paper also reports the estimated frequency of the falls of celestial bodies depending on their size, and consequences of collisions of these bodies with the Earth. It is emphasized that studies of small bodies in the Solar System can provide insight into the origin of the protoplanetary disk and the processes that produced the planets. The studies of small bodies, such as the Chelyabinsk meteorite, are directly related to the problem of asteroid and comet impact hazard (ACIH). The paper reports the sizes of potentially hazardous celestial bodies whose monitoring requires the deployment of a network of specialized telescopes on the Earth to mitigate ACH and a system of space-based systems for the identification and monitoring of such bodies in near space. 相似文献
10.
Richard Schultz Robert T. Pappalardo David A. Ferrill 《Journal of Structural Geology》2006,28(12):2121-2122
Faults have been documented on nearly every solid surface in the solar system, from asteroids to moons to planets, and they provide a remarkable suite of data sets and critical problems for investigation and analysis by structural geologists. The lack of significant atmospheres on Mercury, the Moon, and most outer planet satellites, along with slow erosion rates and a lack of crustal recycling and Earth-like plate tectonics on most planetary bodies, allows for excellent preservation of fault scarp morphologies for study of fault populations and developmental sequences. 相似文献
11.
D. V. Bisikalo I. S. Savanov S. A. Naroenkov M. A. Nalivkin A. S. Shugarov N. S. Bakhtigaraev P. A. Levkina M. A. Ibragimov E. Yu. Kil’pio M. E. Sachkov A. P. Kartashova A. M. Fateeva Marta R. Rodriguez Uratsuka Ramses Zaldivar Estrada Antonio Alonsa Diaz Omar Pons Rodríguez Fidel Hernandes Figuera Maritza Garcia Garcia 《Astronomy Reports》2018,62(6):367-377
The creation of a specialized network of large, wide-angle telescopes for distributed observations of near-Earth space using a Russian–Cuban Observatory is considered. An extremely important goal of routine monitoring of near-Earth and near-Sun space is warding off threats with both natural and technogenic origins. Natural threats are associated with asteroids or comets, and technogenic threats with man-made debris in near-Earth space. A modern network of ground-based optical instruments designed to ward off such threats must: (a) have a global and, if possible, uniform geographic distribution, (b) be suitable for wide-angle, high-accuracy precision survey observations, and (c) be created and operated within a single network-oriented framework. Experience at the Institute of Astronomy on the development of one-meter-class wide-angle telescopes and elements of a super-wide-angle telescope cluster is applied to determine preferences for the composition of each node of such a network. The efficiency of distributed observations in attaining maximally accurate predictions of the motions of potentially dangerous celestial bodies as they approach the Earth and in observations of space debris and man-made satellites is estimated. The first estimates of astroclimatic conditions at the proposed site of the future Russian–Cuban Observatory in the mountains of the Sierra del Rosario Biosphere Reserve are obtained. Special attention is given to the possible use of the network to carry out a wide range of astrophysical studies, including optical support for the localization of gravitational waves and other transient events. 相似文献
12.
Stagnant lid tectonics:Perspectives from silicate planets,dwarf planets,large moons,and large asteroids 总被引：3，自引：1，他引：2
To better understand Earth's present tectonic style-plate tectonics—and how it may have evolved from single plate(stagnant lid) tectonics, it is instructive to consider how common it is among similar bodies in the Solar System. Plate tectonics is a style of convection for an active planetoid where lid fragment(plate) motions reflect sinking of dense lithosphere in subduction zones, causing upwelling of asthenosphere at divergent plate boundaries and accompanied by focused upwellings, or mantle plumes;any other tectonic style is usefully called "stagnant lid" or "fragmented lid". In 2015 humanity completed a 50+ year effort to survey the 30 largest planets, asteroids, satellites, and inner Kuiper Belt objects,which we informally call "planetoids" and use especially images of these bodies to infer their tectonic activity. The four largest planetoids are enveloped in gas and ice(Jupiter, Saturn, Uranus, and Neptune)and are not considered. The other 26 planetoids range in mass over 5 orders of magnitude and in diameter over 2 orders of magnitude, from massive Earth down to tiny Proteus; these bodies also range widely in density, from 1000 to 5500 kg/m~3. A gap separates 8 silicate planetoids with ρ = 3000 kg/m~3 or greater from 20 icy planetoids(including the gaseous and icy giant planets) with ρ = 2200 kg/m~3 or less. We define the "Tectonic Activity Index"(TAI), scoring each body from 0 to 3 based on evidence for recent volcanism, deformation, and resurfacing(inferred from impact crater density). Nine planetoids with TAI = 2 or greater are interpreted to be tectonically and convectively active whereas 17 with TAI 2 are inferred to be tectonically dead. We further infer that active planetoids have lithospheres or icy shells overlying asthenosphere or water/weak ice. TAI of silicate(rocky) planetoids positively correlates with their inferred Rayleigh number. We conclude that some type of stagnant lid tectonics is the dominant mode of heat loss and that plate tectonics is unusual. To make progress understanding Earth's tectonic history and the tectonic style of active exoplanets, we need to better understand the range and controls of active stagnant lid tectonics. 相似文献
13.
The evolution of terrestrial planets (the Earth, Venus, Mars, Mercury, and Moon) was proved to have proceeded according to
similar scenarios. The primordial crusts of the Earth, Moon, and, perhaps, other terrestrial planets started to develop during
the solidification of their global magmatic “oceans”, a process that propagated from below upward due to the difference in
the adiabatic gradient and the melting point gradient. Consequently, the lowest melting components were “forced” toward the
surfaces of the planets in the process of crystallization differentiation. These primordial crusts are preserved within ancient
continents and have largely predetermined their inner structure and composition. Early tectono-magmatic activity at terrestrial
planets was related to the ascent of mantle plumes of the first generation, which consisted of mantle material depleted during
the development of the primordial crusts. Intermediate evolutionary stages of the Earth, Moon, and other terrestrial planets
were marked by an irreversible change related to the origin of the liquid essentially iron cores of these planets. This process
induced the ascent of mantle superplumes of the second generation (thermochemical), whose material was enriched in Fe, Ti,
incompatible elements, and fluid components. The heads of these superplumes spread laterally at shallower depths and triggered
significant transformations of the upper shells of the planets and the gradual replacement of their primordial crusts of continental
type by secondary basaltic crusts. The change in the character of the tectono-magmatic activity was associated with modifications
in the environment at the surface of the Earth, Mars, and Venus. The origin of thermochemical mantle plumes testifies that
the tectono-magmatic process involved then material of principally different type, which had been previously “conserved” at
deep portions of the planets. This was possible only if (1) the planetary bodies initially had a heterogeneous inner structure
(with an iron core and silicate mantle made up of chondritic material); and (2) the planetary bodies were heated from their
peripheral toward central portions due to the passage of a “thermal wave”, with the simultaneous cooling of the outer shells.
The examples of the Earth and Moon demonstrate that the passage of such a “wave” through the silicate mantles of the planets
was associated with the generation of mantle plumes of the first generation. When the “wave” reached the cores, whose composition
was close to the low-temperature Fe + FeS eutectic, these cores started to melt and gave rise to superplumes of the second
generation. The “waves” are thought to have been induced by the acceleration of the rotation of these newly formed planets
due to the decrease of their radii because of the compaction of their material. When this process was completed, the rotation
of the planets stabilized, and the planets entered their second evolutionary stage. It is demonstrated that terrestrial planets
are spontaneously evolving systems, whose evolution was accompanied by the irreversible changes in their tectono-magmatic
processes. The evolution of most of these planets (except the Earth) is now completed, so that they “dead” planetary bodies. 相似文献
14.
鄂西重力地质灾害的研究 总被引：2，自引：0，他引：2
综观鄂西地区岩崩、滑坡、坍方和泥石流等地质灾害的成生，笔者认为大宇宙天体运动控制下的内动力和地质基础背景是其成生变形的主要因素，而与大宇宙天体运动有关的各种外动力条件的影响和变化及人类与生物对自然环境的影响和破坏，则是其成生发展的诱发因素。两种变量（即内、外动力）和天体运动的有机组合与变化趋势，使地质灾害成生的类型及其频度、强度、破坏（形变）特征及变形机制不尽相同，变形特征多样。在发生时间和灾害规模上多受天体运动变化规律所制约。据此可对地质灾害的预测、预报进行更深入地研究，并采取相应的防治措施。 相似文献
15.
Petrova N. K. Nefedyev Yu. A. Zagidullin A. A. Andreev A. O. 《Astronomy Reports》2018,62(12):1021-1025
A brief review of modern observational achievements and the theoretical basis of physical libration of the Moon is presented. Special attention is given to the inferred existence of a lunar core and determination of its parameters. The creation of a theory of physical libration of the Moon, which requires analyses of semi-empirical series of long-term laser observations and the use of the highly accurate DE421 dynamical ephemeris, is related to this. A large role in this area has been played by the analytical theory of physical libration of the Moon constructed by Yu.V. Barkin, which made it possible for the first time to derive parameters of the free nutation of the lunar core from observations. This paper is based on a talk given at the conference “Modern Astrometry 2017,” dedicated to the memory of K.V. Kuimov (Sternberg Astronomical Institute, Moscow State University, October 23–25, 2017).
相似文献16.
在太阳系的形成和演化过程中,发生在天体物质间的撞击作用是最重要的地质过程之一.撞击构造是地外天体表面最常见的地貌单元,大部分天体的地貌演化主要受撞击作用控制.撞击过程产生的温度、压力和应变速率比岩石圈内的其他地质过程高多个数量级,形成广泛分布的撞击产物,如气化物、熔融物、冲击变质和变形等.虽然撞击过程转瞬即逝,撞击作用向天体注入能量并改变其内、外结构,对天体的圈层系统产生长远影响.持续撞击在天体表面累积了大量的撞击坑,撞击坑的空间分布反映了受外来撞击的历史.内太阳系在～3. 8 Ga前的撞击频率更高,但是大量撞击盆地是否灾变式的密集形成仍在持续争议;～3. 8 Ga以来的撞击频率趋于稳定,但是缺乏具有明确事件指代性的标定样品.在同一天体上,撞击坑的空间密度指示了相应地质单元的形成时间,因此撞击坑统计常被用于估算地外天体表面地质单元的相对年龄.基于月球软着陆探测任务返回的样品,前人已约束了不同直径的月球撞击坑的形成频率,进而建立了使用撞击坑统计估算月球表面地质单元的绝对模式年龄的方法.另外,内太阳系天体可能经历了相似的撞击历史,因此地-月系统的撞击频率已被缩放至其他类地行星.撞击坑统计是探索太阳系天体的撞击历史、遥估地外天体表面的相对和绝对年龄的主要方法,也是行星地质研究的基本工具.该方法的整体可靠性已得到大量实验的验证.同时,该方法在理论基础和技术细节上还存在大量的不确定性.修正该方法是完善太阳系撞击历史的重要研究内容,也是未来采样返回探测任务的重要科学目标. 相似文献
17.
An analysis of data from three years of monitoring of interplanetary scintillations in 2015–2017 during a phase of decreasing solar activity is presented. The observations were carried out on the Large Scanning Antenna of the Lebedev Physical Institute at 111 MHz. During the period considered, the spatial distriution of the scintillation level was close to spherically symmetrical, on average, and did not undergo any strong time variations on scales of months or years. The monthly-mean scintillation level is not correlated with theWolf number.
相似文献18.
Perturbed, rotational-oscillational motions of the Earth induced by the gravitational torques exerted by the Sun and Moon are studied using a linear mechanical model for a viscoelastic rigid body. A tidal mechanism is identified for the excitation of polar oscillations, i.e., for oscillations of the angular-velocity vector specified in a fixed coordinate frame, attributed to the rotational-progressive motion of the barycenter of the Earth-Moon “binary planet” about the Sun. The main features of the oscillations remain stable and do not change considerably over time intervals significantly exceeding the precessional period of the Earth’s axis. A simple mathematical model containing two frequencies, namely, the Chandler and annual frequencies, is constructed using the methods of celestial mechanics. This model is adequate to the astrometric measurements performed by the International Earth Rotation Service (IERS). The parameters of the model are identified via least-squares fitting and a spectral analysis of the IERS data. Statistically valid interpolations of the data for time intervals covering from several months to 15–20 yr are obtained. High-accuracy forecasting of the polar motions for 0.5–1 yr and reasonably trustworthy forecasting for 1–3 yr demonstrated by observations over the last few years are presented for the first time. The results obtained are of theoretical interest for dynamical astronomy, geodynamics, and celestial mechanics, and are also important for astrometrical, navigational, and geophysical applications. 相似文献
19.
In this paper, we present three diverse types of applications of extreme value statistics in geology, namely: earthquakes magnitudes, diamond values, and impact crater size distribution on terrestrial planets. Each of these applications has a different perspective toward tail modeling, yet many of these phenomena exhibit heavy or long tails which can be modeled by power laws. It is shown that the estimation of important tail characteristics, such as the extreme value index, is directly linked to the interpretation of the underlying geological process. Only the most extreme data are useful for studying such phenomena, so thresholds must be selected above which the data become power laws. In the case of earthquake magnitudes, we investigate the use of extreme value statistics in predicting large events on the global scale and for shallow intracontinental earthquakes in Asia. Large differences are found between estimates obtained from extreme value statistics and the usually applied standard statistical techniques. In the case of diamond deposits, we investigate the impact of the most precious stones in the global valuation of primary deposits. It is shown that in the case of Pareto-type behavior, the expected value of few extreme stones in the entire deposit has considerable influence on the global valuation. In the case of impact crater distributions, we study the difference between craters distributions on Earth and Mars and distributions occurring on other planets or satellites within the solar system. A striking result is that all planets display the same distributional tail except for Earth and Mars. In a concluding account, we demonstrate the apparent loghyperbolic variation in all of the above-mentioned examples. 相似文献
20.
According to their genesis, meteorites are classified into heliocentric (which originate from the asteroid belt) and planetocentric
(which are fragments of the satellites of giant planets, including the Proto-Earth). Heliocentric meteorites (chondrites and
primitive meteorites genetically related to them) used in this study as a characteristic of initial phases of the origin of
the terrestrial planets. Synthesis of information on planetocentric meteorites (achondrites and iron meteorites) provides
the basis for a model for the genesis of the satellites of giant planets and the Moon. The origin and primary layering of
the Earth was initially analogously to that of planets of the HH chondritic type, as follows from similarities between the
Earth’s primary crust and mantle and the chondrules of Fe-richest chondrites. The development of the Earth’s mantle and crust
precluded its explosive breakup during the transition from its protoplanetary to planetary evolutionary stage, whereas chondritic
planets underwent explosive breakup into asteroids. Lunar silicate rocks are poorer in Fe than achondrites, and this is explained
in the model for the genesis of the Moon by the separation of a small metallic core, which sometime (at 3–4 Ga) induced the
planet’s magnetic field. Iron from this core was involved into the generation of lunar depressions (lunar maria) filled with
Fe- and Ti-rich rocks. In contrast to the parent planets of achondrites, the Moon has a olivine mantle, and this fact predetermined
the isotopically heavier oxygen isotopic composition of lunar rocks. This effect also predetermined the specifics of the Earth’s
rocks, whose oxygen became systematically isotopically heavier from the Precambrian to Paleozoic and Mesozoic in the course
of olivinization of the peridotite mantle, a processes that formed the so-called roots of continents. 相似文献