Einstein, Spacetime, and Planetary Orbits: It's All Relative

2021 ◽  
pp. 69-83
Author(s):  
Tamra Stambaugh ◽  
Emily Mofield
Keyword(s):  
Planetary Orbits

Stability of resonant planetary orbits in binary stars

1989 ◽  
Vol 10 (4) ◽  
pp. 347-365
Author(s):  
M. Michalodimitrakis ◽  
F. Grigorelis
Keyword(s):  
Binary Stars ◽  
Planetary Orbits

scholarly journals On Quadrupole Effects on Planetary Orbits

1976 ◽  
Vol 56 (1) ◽  
pp. 324-326 ◽  
Author(s):  
C. Hoenselaers
Keyword(s):  
Planetary Orbits

scholarly journals CAN GENERAL RELATIVISTIC DESCRIPTION OF GRAVITATION BE CONSIDERED COMPLETE?

1998 ◽  
Vol 13 (17) ◽  
pp. 1393-1400 ◽  
Author(s):  
D. V. AHLUWALIA
Keyword(s):  
Solar System ◽  
Gravitational Potential ◽  
Invariance Properties ◽  
Planetary Orbits ◽  
Galactic Cluster ◽  
General Relativistic ◽  
Relativistic Description ◽  
Flavor Oscillation ◽  
Weak Fields ◽  
Great Attractor

The local galactic cluster, the Great attractor, embeds us in a dimensionless gravitational potential of about -3×10-5. In the solar system, this potential is constant to about 1 part in 1011. Consequently, planetary orbits, which are determined by the gradient in the gravitational potential, remain unaffected. However, this is not so for the recently introduced flavor-oscillation clocks where the new redshift-inducing phases depend on the gravitational potential itself. On these grounds, and by studying the invariance properties of the gravitational phenomenon in the weak fields, we argue that there exists an element of incompleteness in the general relativistic description of gravitation. An incompleteness-establishing inequality is derived and an experiment is outlined to test the thesis presented.

scholarly journals Role of host star variability in the detectability of planetary phase curves

2019 ◽  
Vol 621 ◽  
pp. A44
Author(s):  
D. Hidalgo ◽  
R. Alonso ◽  
E. Pallé
Keyword(s):  
Effective Temperature ◽  
Thermal Emission ◽  
Total Duration ◽  
Phase Curve ◽  
Single Orbit ◽  
Reflected Light ◽  
Planetary Orbits ◽  
Minimum Number ◽  
Temperature Ranges ◽  
Low Amplitude

Phase curves, or the change in observed illumination of the planet as it orbits around its host star, help us to characterize their atmospheres. However, the variability of the host star can make their detection challenging. The presence of starspots, faculae, flares, and rotational effects introduce brightness variations that can hide other flux variations related to the presence of an exoplanet: ellipsoidal variation, Doppler boosting, and a combination of reflected light and thermal emission from the planet. Here we present a study to quantify the effect of stellar variability on the detectability of phase curves in the optical. In the first stage we simulated ideal data, with different white noise levels, and with cadences and total duration matching a quarter of the Kepler mission. We performed injection and recovery tests to evaluate the minimum number of planetary orbits that need to be observed in order to determine the amplitude of the phase curve with an accuracy of 15%. We also evaluate the effect of a simplistic stellar variability signal with low amplitude in order to provide strong constraints on the minimum number of orbits needed under these ideal conditions. In the second stage we applied these methods to data from Q9 of the Kepler mission, known for its low instrumental noise. The injection and recovery tests are performed on a selected sample of the less noisy stars in different effective temperature ranges. Even for the shortest explored planet period of 1 day, we find that observing a single orbit of the planet fails to detect accurately more than 90% of the inserted amplitude. The best recovery rates, close to 48%, are obtained after 10 orbits of a 1 day period planet with the largest explored amplitude of 150 ppm. The temperature range of the host stars providing better recovery ratios is 5500 K < Teff < 6000 K. Our results provide guidelines to selecting the best targets in which phase curves can be measured to the greatest accuracy, given the variability and effective temperature of its host star, which is of interest for the upcoming TESS, CHEOPS, and PLATO space missions.

Planetary Orbits

The Geologist ◽  
1863 ◽  
Vol 6 (12) ◽  
pp. 441-444
Keyword(s):  
Internal Tides ◽  
Wide Difference ◽  
The Earth ◽  
Fluid Core ◽  
Planetary Orbits ◽  
The Absolute

Every day's experience confirms more and more the opinion that the central heat doctrine has less foundation than formerly it was supposed to possess. Its great supporters have gradually increased the necessary thickness of the solid crust in proportion to the internal supposed fluid core from forty to eight hundred miles at least: rather a wide difference in itself, but not perhaps so very great in respect to the absolute diameter of the earth, to which such a relationship would be about in proportion to the thickness of a sheet of cartridge-paper round a 12-inch globe. We know nothing, however, so perfectly a non-conductor that so thin would resist the heat of the internal molten mass. Moreover, upon the alleged increase of temperature with depth in coal and other mines, much doubt has been thrown by the subsequently ascertained facts that in many instances the higher temperatures have disappeared after the mines had ceased to be worked. The necessity, if the interior were fluid, for internal tides below the supposed solid crust, also militates against the existence of a fluid core, because we can detect no such tides at the surface of our earth; and if they existed, it is difficult to conceive the rigidity and strength of so thin a crust to be equal to restraining them entirely; and if the crust were in the least degree yielding or elastic, we must have evidence of such tides in the heavings of the surface.

scholarly journals Angular Momentum and Energy Transfer in a Whitehead's Theory of Gravity

2018 ◽  
Author(s):  
Luis Acedo
Keyword(s):  
Angular Momentum ◽  
Major Axis ◽  
Astronomical Unit ◽  
Net Energy ◽  
Semi Major Axis ◽  
Extended Gravity ◽  
First Case ◽  
Planetary Orbits ◽  
Theory Of Gravity ◽  
New Phenomena

In this paper, we revisit a modified version of the classical Whitehead's theory of gravity in which all possible bilinear forms are considered to define the corresponding metric. Although, this is a linear theory that fails to give accurate results for the most sophisticated predictions of general relativity, such as gravity waves, it can still provide a convenient framework to analyze some new phenomena in the Solar System. In particular, recent development in the accurate tracking of spacecraft and the ephemerides of planetary positions have revealed certain anomalies in relation with our standard paradigm for celestial mechanics. Among them the so-called flyby anomaly and the anomalous increase of the astronomical unit play a prominent role. In the first case the total energy of the spacecraft changes during the flyby and a secular variation of the semi-major axis of the planetary orbits is found in the second anomaly. For this to happen it seems that a net energy and angular momentum transfer is taken place among the orbiting and the central body. We evaluate the total transfer per revolution for a planet orbiting the Sun in order to predict the astronomical unit anomaly in the context of Whitehead's theory. This could lead to a more deeply founded hypothesis for an extended gravity model.

scholarly journals Relativistic mass due to a dilatant vacuum leads to a quantum reformulation of the relativistic kinetic energy

2020 ◽  
Vol 98 (2) ◽  
pp. 142-147
Author(s):  
Marco Fedi
Keyword(s):  
Kinetic Energy ◽  
Higgs Field ◽  
Lorentz Factor ◽  
Viscous Force ◽  
Dark Sector ◽  
Potential Term ◽  
Relativistic Mass ◽  
Planetary Orbits ◽  
Quantum Mechanism ◽  
Relativistic Kinetic Energy

Relativistic mass change with speed is considered here as the effect of a viscous, dilatant vacuum, whose apparent viscosity is related to the Lorentz factor. Transient solid-like vacuum due to shear stress is presented as the reason why vacuum prevents the speed of massive objects from being indefinitely increased. Such a vacuum – that in a previous study allowed to exactly calculate the Pioneer anomaly, Mercury’s perihelion precession, and was shown to be compatible with stable planetary orbits – leads here to a quantum formula for the relativistic kinetic energy. A formula which distinguishes between the case of accelerated charges in a vacuum, for which a Stokes–Einstein radius comes into play, and the case of accelerated macroscopic bodies, for which the quantum potential term vanishes. In this way, incidentally, one obtains again correct results for the Pioneer 10, confirming the role of vacuum’s viscous force. This description of a quantum mechanism underlying the relativistic kinetic energy may be also helpful in constructing a theory of quantum relativity and may even tell us more about the interactions of matter with the Higgs field and the dark sector: two issues which can be themselves linked to a dilatant vacuum.

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