scholarly journals Astrometric solar-system anomalies

2009 ◽  
Vol 5 (S261) ◽  
pp. 189-197 ◽  
Author(s):  
John D. Anderson ◽  
Michael Martin Nieto
Keyword(s):  
Solar System ◽  
Thermal Emission ◽  
New Physics ◽  
Secular Change ◽  
Orbital Energy ◽  
Astronomical Unit ◽  
The Sun ◽  
Sigma Level ◽  
The Earth ◽  
Theory Of Gravitation

AbstractThere are at least four unexplained anomalies connected with astrometric data. Perhaps the most disturbing is the fact that when a spacecraft on a flyby trajectory approaches the Earth within 2000 km or less, it often experiences a change in total orbital energy per unit mass. Next, a secular change in the astronomical unit AU is definitely a concern. It is reportedly increasing by about 15 cm yr−1. The other two anomalies are perhaps less disturbing because of known sources of nongravitational acceleration. The first is an apparent slowing of the two Pioneer spacecraft as they exit the solar system in opposite directions. Some astronomers and physicists, including us, are convinced this effect is of concern, but many others are convinced it is produced by a nearly identical thermal emission from both spacecraft, in a direction away from the Sun, thereby producing acceleration toward the Sun. The fourth anomaly is a measured increase in the eccentricity of the Moon's orbit. Here again, an increase is expected from tidal friction in both the Earth and Moon. However, there is a reported unexplained increase that is significant at the three-sigma level. It is prudent to suspect that all four anomalies have mundane explanations, or that one or more anomalies are a result of systematic error. Yet they might eventually be explained by new physics. For example, a slightly modified theory of gravitation is not ruled out, perhaps analogous to Einstein's 1916 explanation for the excess precession of Mercury's perihelion.

scholarly journals Matahari dalam Perspektif Sains dan Al-Qur'an

2019 ◽  
Vol 2 (1) ◽  
pp. 27-35
Author(s):  
Anisa Nur Afida ◽  
Yuberti Yuberti ◽  
Mukarramah Mustari
Keyword(s):  
Qualitative Research ◽  
Data Analysis ◽  
Solar System ◽  
Data Model ◽  
Research Method ◽  
The Sun ◽  
Data Display ◽  
The Earth ◽  
Library Research ◽  
Analysis Technique

Abstract: This study aims to determine the function of the sun in the perspective of science and al-Qur'an . The research method used is qualitative research methods with the type of research library (Library Research). This research applies data analysis technique of Milles and Huberman model, with steps: 1) data reduction; 2) data display; 3) verification. The result of this research is, the theories that science explain related to the function of the sun in accordance with what is also described in the Qur'an. Science explains that the sun as the greatest source of light for the earth can produce its own energy. This is explained in the Qur'an that the sun is described as siraj and dhiya' which means sunlight is sourced from itself, as the center of the solar system is not static but also moves this matter in the Qur'an explained in QS Yāsin verse 38, besides science and the Qur'an also equally explain that the sun can be made as a calculation of time.Abstrak: Penelitian ini bertujuan untuk mengetahui fungsi matahari dalam perspektif sains dan al-Qur’an..Metode penelitian yang digunakan yaitu metode penelitian kualitatif dengan jenis penelitian pustaka (Library Research). Penelitian ini menggunakan teknik analisis data model Milles dan Huberman, dengan langkah-langkah: 1) reduksi data; 2) display data; 3) verifikasi. Hasil dari penelitian ini yaitu, teori-teori yang sains jelaskan berkaitan dengan fungsi matahari sesuai dengan apa yang juga di jelaskan dalam al-Qur’an. Sains menjelaskan bahwa matahari sebagai sumber energi cahaya terbesar bagi bumi dapat menghasilkan energinya sendiri hal ini dijelaskan dalam al-Qur’an bahwa matahari dideskripsikan sebagai siraj dan dhiya’yang berarti sinar matahari bersumber dari dirinya sendiri, sebagai pusat tata surya matahari tidaklah statis melainkan juga bergerak hal ini dalam al-Qur’an di jelaskan dalam QS Yāsin ayat 38, selain itu sains dan al-Qur’an juga sama-sama menjelaskan bahwa matahari  dapat di jadikan sebagai perhitungan waktu serta petunjuk dari bayang-bayang.

scholarly journals Dust Measurements in the Outer Solar System

1994 ◽  
Vol 160 ◽  
pp. 367-380
Author(s):  
Eberhard Grün
Keyword(s):  
Solar System ◽  
Interstellar Dust ◽  
Thermal Emission ◽  
Scattered Light ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Spatial Density ◽  
Outer Solar System ◽  
The Sun

In-situ measurements of micrometeoroids provide information on the spatial distribution of interplanetary dust and its dynamical properties. Pioneers 10 and 11, Galileo and Ulysses spaceprobes took measurements of interplanetary dust from 0.7 to 18 AU distance from the sun. Distinctly different populations of dust particles exist in the inner and outer solar system. In the inner solar system, out to about 3 AU, zodiacal dust particles are recognized by their scattered light, their thermal emission and by in-situ detection from spaceprobes. These particles orbit the sun on low inclination (i ≤ 30°) and moderate eccentricity (e ≤ 0.6) orbits. Their spatial density falls off with approximately the inverse of the solar distance. Dust particles on high inclination or even retrograde trajectories dominate the dust population outside about 3 AU. The dust detector on board the Ulysses spaceprobe identified interstellar dust sweeping through the outer solar system on hyperbolic trajectories. Within about 2 AU from Jupiter Ulysses discovered periodic streams of dust particles originating from within the jovian system.

scholarly journals Jupiter’s decisive role in the inner Solar System’s early evolution

2015 ◽  
Vol 112 (14) ◽  
pp. 4214-4217 ◽  
Author(s):  
Konstantin Batygin ◽  
Greg Laughlin
Keyword(s):  
Solar System ◽  
Dynamical Evolution ◽  
Decisive Role ◽  
Terrestrial Planets ◽  
The Sun ◽  
Mean Motion Resonances ◽  
The Earth ◽  
Short Period ◽  
Orbital Periods ◽  
Gas Drag

The statistics of extrasolar planetary systems indicate that the default mode of planet formation generates planets with orbital periods shorter than 100 days and masses substantially exceeding that of the Earth. When viewed in this context, the Solar System is unusual. Here, we present simulations which show that a popular formation scenario for Jupiter and Saturn, in which Jupiter migrates inward from a > 5 astronomical units (AU) to a ≈ 1.5 AU before reversing direction, can explain the low overall mass of the Solar System’s terrestrial planets, as well as the absence of planets with a < 0.4 AU. Jupiter’s inward migration entrained s ≳ 10−100 km planetesimals into low-order mean motion resonances, shepherding and exciting their orbits. The resulting collisional cascade generated a planetesimal disk that, evolving under gas drag, would have driven any preexisting short-period planets into the Sun. In this scenario, the Solar System’s terrestrial planets formed from gas-starved mass-depleted debris that remained after the primary period of dynamical evolution.

scholarly journals The early history of the earth

1988 ◽  
Vol 7 (1) ◽  
pp. 38-47
Author(s):  
C. P. Snyman
Keyword(s):  
Solar System ◽  
Laws Of Nature ◽  
Early History ◽  
The Sun ◽  
Natural Phenomena ◽  
The Earth ◽  
History Of ◽  
By Products

In view of the principle of actualism the early history of the earth must be explained on the basis of present-day natural phenomena and the basic Laws of Nature. The study of the solar system leads to the conclusion that the planets were formed as by-products when the sun developed from a rotating cloud of cosmic gas and dust. The protoplanets or planetesimals could have accreted as a result of mutual collisions, during which they could have become partly molten so that they could differentiate into a crust, a mantle and a core on the basis of differences in density.

scholarly journals The Origin of Comets

1972 ◽  
Vol 45 ◽  
pp. 401-408 ◽  
Author(s):  
F. L. Whipple
Keyword(s):  
Solar System ◽  
Refractory Material ◽  
Total Mass ◽  
Terrestrial Planets ◽  
The Sun ◽  
The Earth ◽  
Collapsing Cloud

The evolution of the solar system is surveyed, it being presumed that the Sun, Jupiter, and Saturn formed rather quickly and essentially with the composition of the original collapsing cloud of dust and gas. Just as the refractory material of the cloud is considered to have formed into planetesimals, from which the terrestrial planets collected, so is the icy material supposed to have produced comets, or cometesimals, from which Uranus and Neptune (and to some extent Saturn and Jupiter) were built up. The presence of a residual belt of comets beyond the orbit of Neptune is discussed, analysis of possible perturbative effects on P/Halley indicating that the total mass of such a belt at 50 AU from the Sun could not now exceed the mass of the Earth.

scholarly journals CAPTURE OF DARK MATTER BY THE SOLAR SYSTEM: SIMPLE ESTIMATES

2011 ◽  
Vol 20 (01) ◽  
pp. 17-22 ◽  
Author(s):  
I. B. KHRIPLOVICH
Keyword(s):  
Dark Matter ◽  
Solar System ◽  
Cross Section ◽  
Capture Cross Section ◽  
Dark Matter Particle ◽  
The Sun ◽  
Capture Cross ◽  
The Earth ◽  
Galactic Dark Matter ◽  
Three Body

We consider the capture of galactic dark matter by the solar system, due to the gravitational three-body interaction of the Sun, a planet, and a dark matter particle. Simple estimates are presented for the capture cross-section, as well as for the density and velocity distributions of captured dark matter particles close to the Earth.

Earth's thermospheric evolution and implications for planetary habitability

2020 ◽  
Author(s):  
Colin Johnstone
Keyword(s):  
Carbon Dioxide ◽  
Solar Wind ◽  
Chemical Composition ◽  
Solar System ◽  
Planetary Atmospheres ◽  
Upper Atmosphere ◽  
The Sun ◽  
The Earth ◽  
First Time ◽  
Planetary Habitability

&lt;p&gt;During the Archean eon from 3.8 to 2.5 billion years ago, the Earth's upper atmosphere and interactions with the magnetosphere and the solar wind were likely significantly different to how it is today due to major differences in the chemical composition of the atmosphere and the younger Sun being signifcantly more active. Understanding these factors is important for understanding the evolution of planetary atmospheres within our solar system and beyond. While the higher activity of the Sun would have caused additional heating and expansion of the atmosphere, geochemical measurements show that carbon dioxide was far more abundant during this time and this would have led to significantly thermospheric cooling which would have protected the atmosphere from losses to space. I will present a study of the effects of the carbon dioxide composition and the Sun's activity evolution on the thermosphere and ionosphere of the Archean Earth, studying for the first time the effects of different scenarios for the Sun's activity evolution. I will show the importance of these factors for the exosphere and escape processes of the Earth and terrestrial planets outside our solar system.&lt;/p&gt;

scholarly journals Realization of the Local Inertial Geocentric Frame in Relativity

1990 ◽  
Vol 141 ◽  
pp. 430-430
Author(s):  
He Miao-Fu ◽  
Huang Cheng
Keyword(s):  
Solar System ◽  
Inertial Frame ◽  
The Sun ◽  
Gravitational Effects ◽  
Local Inertial Frame ◽  
Relativistic Corrections ◽  
Tidal Forces ◽  
The Earth

There are two kinds of geocentric frames: local inertial and non-inertial geocentric frames. Ashby et al successfully constructed a local inertial geocentric frame in the neighborhood of the gravitating Earth. In the frame with origin at the Earth's center, the gravitational effects of the sun and of planets other than the Earth are basically reduced to their tidal forces, with very small relativistic corrections.However, the spatial base vectors of the local inertial frame essentially experience the geodesic (or deSitter) precession with respect to the solar system barycentric frame. Hence the realization of the local inertial frame requires that the general precession should exclude the geodesic precession. This requirement is inconsistent with the convention that the amount of geodesic precession is included in that of the general precession given by Lieske et al.

scholarly journals PMOE planetary/lunar ephemeris framework

2007 ◽  
Vol 3 (S248) ◽  
pp. 560-562 ◽  
Author(s):  
G. Y. Li ◽  
H. B. Zhao ◽  
Y. Xia ◽  
F. Zeng ◽  
Y. J. Luo
Keyword(s):  
Solar System ◽  
Earth Tide ◽  
Finite Size ◽  
The Sun ◽  
Ancient China ◽  
Lunar Phases ◽  
The Earth ◽  
Lunar Ephemeris

AbstractThe PMOE planetary/lunar ephemeris framework was established in 2003, and has been improved in recent years. In the framework of the post-Newtonian effects, the figure perturbation effects arising from the a finite size of the Sun, Moon and the Earth, and the effect of the Earth tide were taken into account. The accuracy of using the PMOE ephemeris to predict the positions of the planets in the solar system are the same as that of JPL DE 405. Based on this framework, the orbit optimization for the LISA, ASTROD and ASTROD I missions, and the computation of celestial phenomena and lunar phases in the Xia Shang and Zhou period of ancient China have been completed.

ASTROD–AN OVERVIEW

2002 ◽  
Vol 11 (07) ◽  
pp. 947-962 ◽  
Author(s):  
WEI-TOU NI
Keyword(s):  
Angular Momentum ◽  
Solar System ◽  
Gravitational Wave ◽  
Reference System ◽  
Precise Determination ◽  
The Sun ◽  
Gravitational Wave Detection ◽  
Wave Detection ◽  
The Earth

The objectives of the Astrodynamical Space Test of Relativity using Optical Devices (ASTROD) Mission concept are threefold. The first objective is to discover and explore fundamental physical laws governing matter, space and time via testing relativistic gravity with 3-6 orders of magnitude improvement. Relativistic gravity is an important cornerstone of physics, astronomy and cosmology. Its improved test is crucial to cosmology and modern theories of gravitation including superstring theories. Included in this objective is the precise determination of the relativistic parameters β and γ, the improved measurement of Ġ and a precise determination of an anomalous, constant acceleration directed towards the Sun. The second objective of the ASTROD mission is the high-precision measurement of the solar-system parameter. This includes: (i) a measurements of solar angular momentum via Lense-Thirring effect and the detection of solar g-mode oscillations via their changing gravity field, thus, providing a new eye to see inside the Sun; (ii) precise determination of the planetary orbit elements and masses; (iii) better determination of the orbits and masses of major asteroids. These measurements give better solar dynamics and probe the origin of our solar system. The third objective is to detect and observe gravitational waves from massive black holes and galactic binary stars in the frequency range 50 μHz to 5 mHz. Background gravitational -waves will also be explored. A desirable implementation is to have two spacecraft in separate solar orbit carrying a payload of a proof mass, two telescopes, two 1-2 W lasers, a clock and a drag-free system, together with an Earth reference system. the two spacecraft range coherently with the Earth reference system using lasers. When they are near, they range coherently to each other. The Earth reference system could be ground stations, Earth satellites and/or spacecraft near Earth-Sun Lagrange points. In this overview, we discuss the payload concept, the technological requirements, technological developments, orbit design, orbit simulation, the measurement of solar angular momentum, the gravitational-wave detection sensitivity, and the solar g-mode detection possibility for this mission concept. A simplified mission, Mini-ASTROD with one spacecraft ranging optically with ground stations, together with Super-ASTROD with four spacecraft of 5 AU (Jupiter-like) orbits, will be mentioned in the end. Super-ASTROD is a dedicated low-frequency gravitational-wave detection concept. For Mini-ASTROD, the first objective of ASTROD will be largely achieved; the second objective will be partially achieved; for gravitational wave detection, the sensitivity will be better than the present-day sensitivity using Doppler tracking by radio waves.

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