It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Secular increase of the astronomical unit and perihelion precessions as tests of the Dvali–Gabadadze–Porrati multi-dimensional braneworld scenario
Lorenzo Iorio JCAP09(2005)006 doi: 10.1088/1475-7516/2005/09/006
PDF (313 KB) | HTML | References | Articles citing this article
Viale Unità di Italia 68, 70125, Bari, Italy
Abstract. An unexpected secular increase of the astronomical unit, the length scale of the Solar System, has recently been reported by three different research groups (Krasinsky and Brumberg, Pitjeva, Standish). The latest JPL measurements amount to 7 ± 2 m cy−1. At present, there are no explanations able to accommodate such an observed phenomenon, either in the realm of classical physics or in the usual four-dimensional framework of the Einsteinian general relativity. The Dvali–Gabadadze–Porrati braneworld scenario, which is a multi-dimensional model of gravity aimed at providing an explanation of the observed cosmic acceleration without dark energy, predicts, among other things, a perihelion secular shift, due to Lue and Starkman, of 5 × 10−4 arcsec cy−1 for all the planets of the Solar System. It yields a variation of about 6 m cy−1 for the Earth–Sun distance which is compatible with the observed rate of change for the astronomical unit. The recently measured corrections to the secular motions of the perihelia of the inner planets of the Solar System are in agreement with the predicted value of the Lue–Starkman effect for Mercury, Mars and, at a slightly worse level, the Earth.
6 The increase of the Astronomical Unit
6.1 The observation
From the analysis of radiometric measurements of distances between the Earth and the major planets including observations from Martian orbiters and landers from 1961 to 2003 a secular increase of the Astronomical Unit of approximately 10 m/cy has been reported (36) (see also the article (37) and the discussion therein).
6.2 Search for explanation
Time–dependent gravitational constant and velocity of light This increase cannot be explained by a time–dependent gravitational constant G because the ˙ G/G needed is larger than the restrictions obtained from LLR.
It has also been speculated that a time–dependent change in the velocity of light can be responsible for this effect. Indeed, if the speed of light becomes smaller, than ranging will simulate a drift of distances. However, a inspection of Kepler’s third law
a3 = GM⊙
shows that, if one replaces the distance a by a ranging time a = ct, then effectively the quotient G/c3 appears. Only this combination of the gravitational constant and the speed of light governs the ratio between the orbit time, in our case the orbit time of the Earth. Consequently, a time–dependent speed of light is equivalent to a time–dependent gravitational constant. Since the latter has been ruled out to be possibly responsible for an increase of the Astronomical Unit, also a time–dependent speed of light has to be ruled out.
Cosmic expansion The influence of cosmic expansion by many orders of magnitude too small, see Sec.9.2. Neither the modification of the gravitational field of the Sun nor the drag of the planetary orbits due to the expansion is big enough to explain this drift.
Clock drift An increase of ranged distances might also be due to a drift of the time scale of the form t → t + αt2 for α > 0. This is of the same form as the time drift needed to account for the Pioneer anomaly. From Kepler’s third law one may ask which α is suitable in order to simulate the increase of the Astronomical Unit. One obtains α ≈ 3 · 10−20 s−1 what is astonishing close to the clock drift needed for a clock drift simulation of the pioneer anomaly, see Eq.(16) and below.
7 The quadrupole and octupule anomaly Recently an anomalous behavior of the low–l contributions to the cosmic microwave background has been reported. It has been shown that (i) there exists an alignment between the quadrupole and octupole with > 99.87% C.L. , and (ii) that the quadrupole and octupole are aligned to Solar system ecliptic to > 99% C.L. . No correlation with the galactic plane has been found.
The reason for this is totally unclear. One may speculate that an unknown gravitational field within the Solar system slightly redirects the incoming cosmic microwave radiation (in the similar way as a motion with a certain velocity with respect to the rest frame of the cosmological background redirects the cosmic background radiation and leads to modifications of the dipole and quadrupole parts). Such a redirection should be more pronounced for low–l components of the radiation. It should be possible to calculate the gravitational field needed for such a redirection and then to compare that with the observational data of the Solar system and the other observed anomalies.
8.2 Other anomalies?
There is one further observation which status is rather unclear bit which perhaps may fit into the other observations. This is the observation of the return time of comets: Comets usually come back a few days before they are expected when applying ordinary equations of motion. The delay usually is assigned to the outgassing of these objects. In fact, the delay is used for an estimate of the strength of this outgassing. On the other hand, it has been calculated in (44) that the assumption that starting with 20 AU there is an additional acceleration of the order of the Pioneer anomaly also leads to the effect that comets come back a few days earlier. It is not clear whether this is a serious indications but a further study of the trajectories of comets certainly is worthwhile.
Evidence Mounts For Companion Star To Our Sun
by Staff Writers
Newport Beach CA (SPX) Apr 25, 2006
The Binary Research Institute (BRI) has found that orbital characteristics of the recently discovered planetoid, Sedna, demonstrate the possibility that our sun might be part of a binary star system. A binary star system consists of two stars gravitationally bound orbiting a common center of mass.
Once thought to be highly unusual, such systems are now considered to be common in the Milky Way galaxy.
Walter Cruttenden at BRI, Professor Richard Muller at UC Berkeley, Dr. Daniel Whitmire of the University of Louisiana, amongst several others, have long speculated on the possibility that our sun might have an as yet undiscovered companion. Most of the evidence has been statistical rather than physical.
The recent discovery of Sedna, a small planet like object first detected by Cal Tech astronomer Dr. Michael Brown, provides what could be indirect physical evidence of a solar companion. Matching the recent findings by Dr. Brown, showing that Sedna moves in a highly unusual elliptical orbit, Cruttenden has determined that Sedna moves in resonance with previously published orbital data for a hypothetical companion star.
In the May 2006 issue of Discover, Dr. Brown stated: "Sedna shouldnt be there. Theres no way to put Sedna where it is. It never comes close enough to be affected by the sun, but it never goes far enough away from the sun to be affected by other stars... Sedna is stuck, frozen in place; there's no way to move it, basically there's no way to put it there – unless it formed there. But it's in a very elliptical orbit like that. It simply can't be there. There's no possible way - except it is. So how, then?"
"I'm thinking it was placed there in the earliest history of the solar system. I'm thinking it could have gotten there if there used to be stars a lot closer than they are now and those stars affected Sedna on the outer part of its orbit and then later on moved away. So I call Sedna a fossil record of the earliest solar system. Eventually, when other fossil records are found, Sedna will help tell us how the sun formed and the number of stars that were close to the sun when it formed."
Within the Newtonian framework, we considered the action of a circular massive ring modeling the Edgeworth-Kuiper belt of Trans-Neptunian Objects, but it does not induce secular variations of e. In principle, a viable candidate would be a putative trans-Plutonian massive object (PlanetX/Nemesis/Tyche), recently revamped to accommodate certain features of the architecture of the Kuiper belt and of the distribution of the comets in the Oort cloud, since it would cause a non-vanishing long-term variation of the eccentricity.Actually, the values for its mass and distance needed to explain the empirically determined increase of the lunar eccentricity would be highly unrealistic and in contrast with the most recent viable theoretical scenarios for the existence of such a body. For example, a terrestrial-sized body should be located at just 30 au, while an object with the mass of Jupiter should be at 200 au.