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Hypothesis of a daemon kernel of the Earth
Abstract
The paper considers the fate of the electrically charged (Ze~10e) Planckian elementary black holes - daemons - making up the dark matter (DM) of the Galactic disk, which, as follows from our measurements, were trapped by the Earth during 4.5 Gyr in an amount of ~10^24. Due to their huge mass (~2x10^(-8)kg), these particles settle down to the Earth's center to form a kernel. Assuming the excess flux of 10-20 TW over the heat flux level produced by known sources, which is quoted by many researchers, to be due to the energy liberated in the outer kernel layers in daemon-stimulated proton decay of iron nuclei, we have come to the conclusion that the Earth's kernel is presently measured in few fractions of meter in size. The observed mantle flux of 3He (and the limiting 3He/4He ~ 10^(-4) ratio itself) can be provided if at least one 3He(or 3T) nucleus is emitted in a daemon-stimulated decay of ~100-1000 Fe nuclei. This could remove actually the only objection to the hot origin of the Earth and to its original melting. The high energy liberation at the center of the Earth drives two-phase two-dimensional convection in its inner core (IC), with rolls oriented along the rotation axis. This provides an explanation for the numerous features in the IC structure revealed in the recent years. The energy release in the kernel grows continuously as the number of daemons in it increases. Therefore the global tectonic activity, which had died out after the initial differentiation and cooling off of the Earth was reanimated ~2 Gyr ago by the rearrangement and enhancement of convection in the mantle as a result of the increasing outward energy flow. It is pointed out that as the kernel continues to grow, the tectonic activity will become intensified rather than die out, as this was believed before.
... On the other hand, part of the NEACHO daemons, on crossing the Earth, will become captured into Geocentric Earth-Surface Crossing Orbits (GESCOs), which contract gradually (in a time of a few months) to escape under the surface of the Earth as its material slows the daemons down [2,24]. The objects populating these orbits have near-surface velocities of 11 to 0 km/s. ...
... (a) the daemon flux (f ⊕ ~ 10 -7 −10 -6 cm -2 s -1 ), a figure in agreement with the fairly low efficiency of our detector, which is triggered only by a part of the daemons crossing it; this stresses the need for further refinement of the parameters of the Earth's daemon kernel [24]; ...
The "Troitsk anomaly" is a strange bump at the end of the tritium beta spectrum observed in electron antineutrino mass measurements. It reveals a half-year variation. The nature of the anomaly can be accounted for by interaction of negative DArk Electric Matter Objects - daemons detected by us with the Nb-containing superconducting coils of the gaseous tritium source of the setup. In crossing the system, the daemons, whose flux varies with a half-year period, drag away Nb-containing clusters and excite their nuclei and electronic shells to produce emission of five Auger electron lines within E = 18566-18572 eV. This yields an estimate for the daemon flux ~10-7-10-6 cm-2s-1. It is shown that in the KATRIN system (KArlsruhe TRItium Neutrino experiment) presently under construction the ratio of the daemon-stimulated Auger bump signal to the useful beta-signal should be larger than that in the Troitsk experiment. The potential of using slightly modified systems at Troitsk and Karlsruhe to study the daemons is pointed out.
... Initially, rather than delving into the fundamental essence of the processes underlying the celestial mechanics, we invoked a simplified concept of a "shadow", which is produced by daemons captured into SEECHOs from the galactic disk by the moving Sun, and of the corresponding "antishadow" created by some daemons crossing the Sun in the opposite direction (i.e., in the direction of its motion), an approach that had been reflected in our earlier publications (Drobyshevski, 2004;Drobyshevski et al., 2003). ...
... Indeed, estimates of the velocity with which daemons escape from geocentric Earthcrossing orbits (GESCO) into the Earth suggest that the resistance offered by a metal-like solid to a daemon moving with a velocity of ~10 km/s is ~10 -5 dyne (Drobyshevski, 2004), which entails a release of thermal energy of ~6 MeV/cm. It is unclear what energy would be liberated in a dielectric (without conductive electrons) scintillator. ...
The assumption of the capture by the Solar System of the electrically charged Planckian DM objects (daemons) from the galactic disk is confirmed not only by the St.Petersburg (SPb) experiments detecting particles with V<30 km/s. Here the daemon approach is analyzed considering the positive model independent result of the DAMA/NaI experiment. We explain the maximum in DAMA signals observed in the May-June period to be associated with the formation behind the Sun of a trail of daemons that the Sun captures into elongated orbits as it moves to the apex. The range of significant 2-6-keV DAMA signals fits well the iodine nuclei elastically knocked out of the NaI(Tl) scintillator by particles falling on the Earth with V=30-50 km/s from strongly elongated heliocentric orbits. The half-year periodicity of the slower daemons observed in SPb originates from the transfer of particles that are deflected through ~90 deg into near-Earth orbits each time the particles cross the outer reaches of the Sun which had captured them. Their multi-loop (cross-like) trajectories traverse many times the Earth's orbit in March and September, which increases the probability for the particles to enter near-Earth orbits during this time. Corroboration of celestial mechanics calculations with observations yields ~1e-19 cm2 for the cross section of daemon interaction with the solar matter.
... The resistance of the Earth's matter leads to a gradual shrinking of the GESCOs. As a result, a daemon kernel is formed at the Earth's center, which accounts for a multitude of geophysical facts [5]. ...
DEMs have been used to experimental studying the temporal evolution of the
March maximum of fluxes of near-Earth daemons. It is shown that part of objects
from near-Earth almost circular heliocentric orbits (NEACHOs), from which a
rather intense flux proceeds during only about four weeks, forms in the second
half of March the population in geocentric Earth-surface-crossing orbits
(GESCOs). The resistance of the Earth's matter results in that GESCO objects
sink into the Earth's interior, so that the GESCO population nearly disappears
by the end of April.
Universal antigravitation, a new physical phenomenon discovered astronomically at distances of 5 to 8 billion light years, manifests itself as cosmic repulsion that acts between distant galaxies and overcomes their gravitational attraction, resulting in the accelerating expansion of the Universe. The source of the antigravitation is not galaxies or any other bodies of nature but a previously unknown form of mass/energy that has been termed dark energy. Dark energy accounts for 70 to 80% of the total mass and energy of the Universe and, in macroscopic terms, is a kind of continuous medium that fills the entire space of the Universe and is characterized by positive density and negative pressure. With its physical nature and microscopic structure unknown, dark energy is among the most critical challenges fundamental science faces in the twenty-first century.
Travel-time residuals of the PKIKP phase observed between 170° and 180° show an axisymmetric pattern of degree 2 with an amplitude of about 2 seconds. The effect at shorter distances is much less pronounced and the entire data set cannot be explained by a physically realistic radial distribution of (isotropic) heterogeneity. We propose that, in addition to the general (isotropic) heterogeneity, the inner core is anisotropic with cylindrical symmetry aligned with the earth's rotation axis. Average P-velocity along this axis is about 1 percent faster than in the equatorial plane.
The inner core has the intriguing property that seismic waves traveling
parallel to the Earth's spin axis arrive earlier than those traveling
parallel to the equatorial plane. The travel time is some 6 s faster
from pole to pole than across the equator. This difference is not the
result of different polar and equatorial radii of the inner core, for it
would require the inner core to be elongated at the poles by more than
one third of its radius. Rather, this 6-s travel time difference is the
result of the inner core's being anisotropic; wave speeds differ for
different directions of wave propagation. This anisotropy, discovered
only in the last decade, is characterized by cylindrical symmetry about
an axis approximately aligned with the Earth's spin axis. The anisotropy
is believed to be due to a preferred orientation of anisotropic iron
crystals composing the inner core, but the mechanisms responsible for
creating such a preferred orientation remain uncertain. With the
anisotropy now well established as a basic property of the inner core,
its quantification and that temporal variations of its orientation have
become a vital tool for probing the structure, composition, and dynamics
of the Earth's deep interior.
Based mainly on original experimental data obtained in the Soviet Union. The first part of the book provides a description of mass-spectrometric techniques and measurements of the helium isotope abundance. The second part discusses recent data on the origin and distribution of helium isotopes in meteorites, in the Earth's mantle, the crust and ocean, and in the atmosphere. The final chapter presents a model of the earth degassing and differentiation.-from Publisher
Seismological studies indicate that the inner core of Earth is anisotropic for compressional waves (P waves), and has low shear wave (S wave) velocity, and high seismic attenuation. Using an effective medium theory for composite materials, we show that the presence of a volume fraction of 3 to 10% liquid in the form of oblate spheroidal inclusions aligned in the equatorial plane between iron crystals is sufficient to explain the aforementioned seismic phenomena. Variation of S-wave velocity between the polar axis and equatorial plane is more sensitive to the addition of liquid than that of P waves. The liquid could arise from the presence of dendrites or a mixture of elements other than iron that exist in liquid form under inner-core conditions.
Seismological images of the Earth's mantle reveal three distinct changes in velocity structure, at depths of 410, 660 and 2,700 km. The first two are best explained by mineral phase transformations, whereas the third-the D" layer-probably reflects a change in chemical composition and thermal structure. Tomographic images of cold slabs in the lower mantle, the displacements of the 410-km and 660-km discontinuities around subduction zones, and the occurrence of small-scale heterogeneities in the lower mantle all indicate that subducted material penetrates the deep mantle, implying whole-mantle convection. In contrast, geochemical analyses of the basaltic products of mantle melting are frequently used to infer that mantle convection is layered, with the deeper mantle largely isolated from the upper mantle. We show that geochemical, seismological and heat-flow data are all consistent with whole-mantle convection provided that the observed heterogeneities are remnants of recycled oceanic and continental crust that make up about 16 and 0.3 per cent, respectively, of mantle volume.
Seismological body-wave and free-oscillation studies of the Earth's solid inner core have revealed that compressional waves traverse the inner core faster along near-polar paths than in the equatorial plane. Studies have also documented local deviations from this first-order pattern of anisotropy on length scales ranging from 1 to 1,000 km (refs 3, 4). These observations, together with reports of the differential rotation of the inner core, have generated considerable interest in the physical state and dynamics of the inner core, and in the structure and elasticity of its main constituent, iron, at appropriate conditions of pressure and temperature. Here we report first-principles calculations of the structure and elasticity of dense hexagonal close-packed (h.c.p.) iron at high temperatures. We find that the axial ratio c/a of h.c.p. iron increases substantially with increasing temperature, reaching a value of nearly 1.7 at a temperature of 5,700 K, where aggregate bulk and shear moduli match those of the inner core. As a consequence of the increasing c/a ratio, we have found that the single-crystal longitudinal anisotropy of h.c.p. iron at high temperature has the opposite sense from that at low temperature. By combining our results with a simple model of polycrystalline texture in the inner core, in which basal planes are partially aligned with the rotation axis, we can account for seismological observations of inner-core anisotropy.
A first principles theoretical approach shows that, at the density of the inner core, both hexagonal [hexagonal close-packed
(hcp)] and cubic [face-centered-cubic (fcc)] phases of iron are substantially elastically anisotropic. A forward model of
the inner core based on the predicted elastic constants and the assumption that the inner core consists of a nearly perfectly
aligned aggregate of hcp crystals shows good agreement with seismic travel time anomalies that have been attributed to inner
core anisotropy. A cylindrically averaged aggregate of fcc crystals disagrees with the seismic observations.
Observational data on the processes in the Earth's core obtained by various astrometric and geophysical methods are discussed. These data suggest that the inner core is mobile within the Earth and that its axial rotation differs from the rotation of the planet as a whole. A strategy of consistent observations (gravimetric, seismological, magnetometric, and astrometric) is proposed, making it possible to determine characteristic periods of inner core mobility and constrain a model generalizing the relationship between the observed processes.
In an effort to confirm inner core anisotropy, we conducted a systematic search for PKP ray paths with various angles from the Earth's spin axis. In particular, we studied paths nearly parallel to the spin axis (polar paths) and those nearly parallel to the equatorial plane (equatorial paths). Data for earthquakes and explosions were collected from Worldwide Standardized Seismograph Network (WWSSN), Long Range Seismic Measurements (LRSM), and Global Digital Seismograph Network (GDSN). Absolute times (DF, BC) and differential times (BC-DF, AB-DF) as well as waveform data were examined. For all polar paths, differential times of BC-DF consistently yield residuals of 1.5 to 3.5s larger than equatorial paths. Absolute DF time residuals exhibit anomalies of the same magnitude (1 to 4s) with DF being early along polar paths while BC residuals have no obvious correlation with the differential time anomalies. DF phases appear multi-pathed for polar paths and are relatively simple for equatorial paths. These results coupled with previous studies suggest an axisymmetric anisotropy at the top of the inner core.
The difference between the travel times of compressional waves that turn in the earth's liquid outer core (PKP-BC) and those that run in the solid inner core (PKIKP-DF) is primarily sensitive to structure near the inner core boundary. Such differential travel times measured from short-period waveforms are consistent with small-amplitude deviations from radial symmetry except when ray paths are nearly parallel to the earth's spin axis. These near-axial paths consistently produce large travel-time anomalies, providing compelling evidence for large-amplitude, axisymmetric anisotropy in the outermost portions of the inner core.
Previous hypotheses concerning the cause of anomalous splitting in free oscillation spectra have led to models which are difficult to accept from the physical point of view - involving either substantial heterogeneity in the fluid outer core or large topographic variations in the core-mantle boundary and the inner core boundary and heterogeneity of several percent in inner core properties. Furthermore, other seismological evidence, some of it pre-existing and some of it very recently discovered, militates against these models. Within the framework of isotropic earth models there appears to be no acceptable explanation of the modal observations. Here we show that anisotropy in the inner core can produce an effect which is of the correct magnitude and which varies from mode to mode in approximately the observed manner. The data currently available are insufficient to objectively map the anisotropy, but the simple assumption of a constant elastic tensor which is invariant under rotations about the Earth's rotation axis (i.e. is transversely isotropic in the plane of the equator) matches well the gross features of the modal observations. This model does not entirely reconcile the modal data with traveltime observations; it is argued, however, that there exists an anisotropic model which will do so.
G. Gamov's point of view on the origin of the Solar System is presented. He was skeptical concerning the modern wide-spread nebular approach to the formation of planets. At the same time, he stopped quite close to the close-binary hypothesis considering the Sun-Jupiter system as the limiting case of a close binary. The latter approach is developed in detail here. The observed close binary systems appear after 4–5 fragmentations of a cloud with excessive angular momentum as a result of rotational-exchange fission of the last fragment-a fast-spinning cloud with density 10 − 10 g/cm. Due to high density, the cloud rapidly collapses according to classical Hayashi scenario, with the appearance of a protostar with an outer convective zone. For M < 1 − 1.5M⊙ this zone spans the whole protostar, while for M < 1.5M⊙ it occupies only a part of its mass. In a protostar whose dense inner part rotates faster than its periphery, large angular momentum is stored. When the convection arises, momentum is carried outwards and the outer layers form a massive ring breaking up into self-gravitating fragments. The convective matter of the protostar flows through the inner Lagrangian point to the heaviest fragment. Thus, rotational-exchange fission of a star with M < 1.5M⊙ produces a close binary with components of comparable mass. In the M < 1.5M⊙ case, the matter of the whole star flows onto a newly formed component, so that only a remnant with M∼ 0.001M⊙ is left behind. So the limiting case of a close binary star is the Sun-Jupiter type system (E. M. Drobyshevski, Nature 250, 35, 1974). The other planets were formed within the originally massive and fast-rotating component, a very dense analog of a classical protoplanetary disk, and were lost, except for the last Galilean satellites, because of rapid mass decrease of this component-future Jupiter. This model explains all properties of the Solar System, including slow rotation of the Sun and fast rotation of the planets, and predicts the existence of a planet-cometary cloud containing dozens of moon-like planets at a distance of only 50–3,000 AU (E. M. Drobyshevski, Moon Planets 18, 145, 1978). It predicts also the presence of planets in some binary systems.
A month-long observation of two horizontal mutually light-isolated scintillating screens, 1 v m 2 in area and located one above the other a certain distance apart, revealed about 15 correlated signals, whose time shift corresponds to an average velocity of only ∼10-15 v km v s m 1 . We assign the origin of these signals to the negative daemons, i.e. electrically charged Planckian particles which supposedly form the DM in the Galactic disc, captured into the near- Earth orbits. As follows from an analysis of the factors accompanying the signals and governing their properties, the key part in the detection of daemons is played apparently by two processes: (i) nucleon decay in the daemon-containing nucleus, and (ii) emission of energetic electrons and nucleons in the capture of a nucleus of atom by a daemon. The first process results in the release by daemons of the heavy nuclei captured by them in traversing the components of the system (S, Fe, Zn, Sn etc.), and the second, in excitation of the main part of the scintillations observed in the ZnS(Ag) phosphor. The flux of slow daemons through the Earth's surface estimated from the measurements is ∼10 m 9 v cm m 2 v s m 1 .
The inner core of the earth most likely consists of epsilon (hcp) iron
and shows anisotropy of seismic velocities which could be explained by
crystallographic preferred orientation developing during convective
flow. This paper summarizes deformation mechanisms in hcp metals and
applies the Taylor theory of polycrystal deformation to analogs of
epsilon-iron for different strain histories. The pattern of preferred
orientation is then used to calculate elastic properties of deformed
polycrystals with special emphasis on anisotropy.
Estimation of the Rayleigh number of the Earth's inner core suggests that this region is convecting. The flow pattern is likely to produce crystallographic preferred orientation of the elastically anisotropic hexagonal closest packed (ε) phase of iron, such that compressional-wave velocities would be greater in the axial relative to the equatorial direction by roughly 1 percent. This result is in agreement with seismological evidence that the inner core is elastically anisotropic.
Olivine and clinopyroxene phenocrysts contained in late Tertiary basalts from Selardalur, northwest Iceland, carry volatiles with the highest helium isotope ratio yet reported for any mantle plume. 3He/4He ratios measured on three different samples and extracted by stepped crushing in vacuo fall consistently ˜37 RA (RA = air 3He/4He) — significantly higher than previously reported values for Iceland or Loihi Seamount (see K.A. Farley, E. Neroda [Annu. Rev. Earth Planet. Sci. 26 (1998) 189–218]). The Sr, Nd and Pb isotopic composition of the same sample places it towards the center of the mantle tetrahedron of Hart et al. (S.R. Hart, E.H. Hauri, L.A. Oschmann, J.A. Whitehead [Science 256 (1992) 517–520]) — in exactly the region predicted for the common mantle endmember based on the convergence of a number of pseudo-linear arrays of ocean island basalts worldwide (E.H. Hauri, J.A. Whitehead, S.R. Hart [J. Geophys. Res. 99 (1994) 24275–24300]). This observation implies that Selardalur may represent the best estimate available to date of the He–Sr–Nd–Pb isotopic composition of the 5th mantle component common to many mantle plumes.
A question whether thermal convection occurs in the solid inner core or not is not yet completely solved. In this paper the temperature profile in the core is examined when the solid core grows, being cooled from the surface. In order for convection to occur, the temperature gradient must exceed the adiabatic gradient. In the solid inner core, temperature due to thermal conduction is calculated and compared with the adiabatic temperature. In the outer core, temperature is assumed to be adiabatic due to vigorous fluid convection. The temperature gradient in the solid inner core has been estimated under different conditions, i.e., for different growth rates and different concentration of radioactive material, but it has been found that it can never exceed the adiabatic gradient. If we assume that the inner core has been solidified to the present size in 4.5 billion years, the temperature decreases, maintained almost isothermal inside the inner core. Even if it has been formed in such a short period as 1.5 billion years, the temperature gradient is still much smaller than the adiabat. This indicates that no thermal convection can occur. Presence of radiogenic heat sources raises the temperature, but even with such a high concentration as 100 ppm of K no convection is likely to occur.
Processes involved in the tectonic activity of the earth and in the
mechanism of the formation of the earth's crust are examined. Particular
attention is given to complex problems related to geodynamics and to
evolutionary and genetic geology, which are investigated systematically
in the framework of the theory of geology. Latest findings in the areas
of lithospheric platform tectonics and the origins of the terrestrial
hydrosphere and atmosphere are discussed.
Considering a coincidence of detected solar neutrino flux with the
predicted pp solar neutrino flux, the practically zero contribution of
the electron capture (^7Be, pep) neutrinos may be interpreted as
evidence for the pp reaction being catalysed by some multicharged
negative particles that make up the dark matter in the Universe,
including the galactic disc. Elementary black holes with a mass
(piħc/4G)^1/2=1.93x10^-5 g, determined by 1/4 of their Compton
wavelength, and the corresponding, presumably stable, charge
Ze<=G ^1/2M=10e, are proposed as possible
candidates for such DArk Electric Matter Objects, or DAEMONs. DAEMONs
are captured efficiently by the Sun, and their number accumulated by the
present time (~10^30) is large enough for the reactions bursting at a
rate of ~10^8 s^-1 in the `atomic' shells formed around them by protons
and other light nuclei to account for most of the solar luminosity. The
standard problem of catalyst poisoning by heavy nuclei is not fatal for
DAEMONs; indeed, since they are multiply charged, the nuclei can react
in the DAEMON shells with one another (primarily with protons already in
the Rydberg states) and, therefore, become lost; the nuclei can also
fall below the relativistic horizon of a DAEMON in a comparatively short
time. Some implications, relevant problems, and directions of further
development of the proposed approach are pointed out, in particular the
need for constructing cosmological scenarios that would take into
account the specific properties of DAEMONs, and the physics of the
DAEMONs themselves (charge conservation conditions for
Z<~ 1, instability of the DAEMON-containing
nucleons, etc.).
We start from the hypothesis that the dark matter of the Galactic disc
contains Planckian particles carrying a negative electric charge of up
to Z=10, which we call dark electric matter objects (daemons). Daemons
are capable of catalysing proton-fusion reactions, which may account for
the observed solar neutrino deficiency. The inevitable poisoning of the
catalytic property of daemons as they capture heavy nuclei (A>=20) in
the interior of the Sun is used to estimate the decay time of a
daemon-containing nucleus (nucleon) in quantum-relativistic processes,
which remain largely unknown. This time is
τex~10-7s. This may mean that the lower limit
on the mass of an intranucleonic particle interacting with a daemon is
~108-1010GeV and, possibly, even
~1014-1015GeV. The desirability of a search for
multiple events occurring with an interval ~τex along the
`slow' daemon trajectories on operating installations dedicated to
detection of the proton decay is pointed out.
SOLIDITY of the inner core was originally inferred on the basis of the assumption that the inner core has the same composition as the surrounding material of the outer core1. If, however, the observed increase in compressional velocity is related to a compositional change or, as suggested by Elsasser and Isenberg2, to a new phase of iron with rearranged electronic orbits, then the inner core might be liquid3. It was believed that conclusive evidence of solidity of the inner core would come from observations of body waves of the type PKJKP, SKJKS or SKJKP, phases that travel through the inner core as a shear wave. But no reliable observations of these phases have been reported so far.
Recent seismological studies have suggested that the inner core is rotating relative to the bulk of the Earth, a situation which (according to numerical simulations) may be sustained by convective flow in the liquid outer core. On the other hand, large gravitational forces due to the heterogeneous distribution of mass in the Earth's mantle should be sufficient to keep the inner core aligned with the mantle. Here I show that the differential rotation of the inner core can be reconciled with these strong gravitational forces by allowing, the shape of the inner core to adjust as it rotates, so permitting an estimate of the effective viscosity of this innermost region of the Earth. The inferred rotation rate con strains the viscosity of the inner core to be less than 1016 Pas or greater than 1020 Pas, as two different dynamical regimes are possible. The viscosity estimates for these two regimes have very different implications for the origin of seismic anisotropy in the inner core.
The inner core has long been recognized as a part of the process by which fluid core convection is maintained and as an influence upon the magnetic field. Evidence from several seismological studies in recent years has mounted to indicate that the inner core has anisotropic velocities with large-scale (degree one) variation in strength of the differences from isotropy, and fine-scale (a few kilometres) inhomogeneities of structure. Indications have also been found of systematic changes in the travel time of seismic waves passing through the inner core – which have been interpreted as evidence that the inner core is rotating in an easterly direction, relative to the mantle, at a rate fast enough to be perceived on human timescales. The rate has been dismissed as too slow or physically impossible, but additional evidence has accumulated in support of what may be an emerging consensus that the inner core has a super-rotation of a few tenths of a degree per year.
Although the Earth’s inner core has long been thought to be solid, there have not, as yet, been unequivocal observations of inner core shear waves. Here we present observations of the phases pPKJKP and SKJKP for the Flores Sea event of 1996 June 17. The observations support the value of approximately 3.6 km s− 1 for the inner core shear wave velocity and open up new possibilities for exploring the anisotropic structure and the attenuation properties of the inner core. The analysis and validation of the observation is based on a new method that can be used in the search for and identification of inner core shear waves. In this method normal mode synthetics for a solid inner core are compared with those for a fluid inner core. It is only by such comparisons that it is possible to be certain that inner core shear waves, rather than interferences of other phases, are responsible for observed energy maxima in stacked seismic records.
The spectra of 25 inner-core-sensitive normal modes observed following eight recent major (Mw >7.5) earthquakes are inverted for anisotropic structure in the inner core, using a one-step inversion procedure. The mode data are combined with PKP(DF)–PKP(AB) differential traveltime data and the inner core is parametrized in terms of general axisymmetric anisotropy, allowing structure beyond restrictive transversely isotropic models with radially varying strength. The models obtained are in good agreement with previous ones derived through the intermediate step of computing splitting functions. Splitting functions predicted for the inner core model determined using the one-step, direct inversion of all mode spectra agree well with those obtained from non-linear inversion of individual modes. We discuss the importance of handling the perturbation to radial isotropic structure appropriately in order to align the observed and predicted spectra properly. We examine the effect of using existing tomographic mantle models to correct for mantle effects on the inner core modes versus a mantle model derived by us using a relatively small number of mantle-sensitive modes, and show that the latter leads to a significantly better fit to the inner core data. Our ability to fit the inner core spectral data degrades appreciably if an isotropic layer thicker than 100–200 km is imposed at the top of the inner core.
Tomographic images reveal an apparent fundamental disagreement in the interpretations of seismic data pertaining to the depth of the source of lavas erupted in the Iceland region and the assumptions in helium geochemistry modelling. Four recent independent tomography experiments image a major, strong, low-wave-speed anomaly in the upper mantle beneath Iceland that does not continue down into the lower mantle, confirming earlier studies. On the other hand, some 3He/4He ratios measured in volcanic rocks from the Iceland region are amongst the highest on Earth. Elevated 3He/4He ratios are conventionally viewed as resulting from excess 3He from a little-degassed, primitive reservoir, often assumed to be in the lower mantle, and a high 3He/4He ratio is regarded as the most powerful geochemical indicator of a lower mantle plume. Suggested explanations for this disagreement include a model whereby material is transported up from the lower mantle by a structure that is too small to be detected by seismic tomography, and a model whereby high 3He/4He ratios arise from the upper mantle. These results have significant implications for models of plumes elsewhere.
If the solar system origin is considered within the framework of the author's hypothesis on the binary stars formation as a result of rotational-exchange break-up of the rotating protostar, then difficulties involved in the usual nebular hypotheses are automatically removed (unclear aspects of the possibility of formation of the gas disc proper, the problems of the angular momentum including slow rotation of the Sun and coplanarity of the planetary orbits, of differences in planetary masses and composition, the need, for the disc remnants to be swept out, the long time of planetary formation as compared with the possible lifetime of a turbulized disc etc.).
The major stages of division and evolution of the Jupiter-Sun system are described. Similarities between the massive rotating proto-Jupiter (PJ) and the classical protoplanetary discs are pointed out. The process of planetoid condensation inside PJ is discussed. The most probable site of the condensation is the region of the first Lagrangian point. The planetoids condensed were lost by PJ as a result of its fast mass decrease. A gas dynamic consideration of the motion of planetoids in PJ yields 1000–3000 yr as a time scale for the PJ's mass loss. The number of the moonlike bodies lost (the remaining Galilean satellites fixing their lower mass limit) could reach 104.
Evolution of such interacting bodies results in the formation beyond Neptune of a cloud (up to 103) of moonlike (and more massive) planets.
The excess concentration of the long-period comets aphelia in this area implies their genetic relation to the planets. A concept of a joint planeto-cometary cloud is introduced. A concrete hydrodynamic mechanism of ice ejection from planets into space, viz. the formation of cumulative (Monroe) jets, is pointed out.
A program of further investigations is outlined and recommendations given for an experimental check on the implications of the new cosmogonic concepts.
A large data set consisting of about 1000 normal mode periods, 500 summary travel time observations, 100 normal mode Q values, mass and moment of inertia have been inverted to obtain the radial distribution of elastic properties, Q values and density in the Earth's interior. The data set was supplemented with a special study of 12 years of ISC phase data which yielded an additional 1.75 × 10^6 travel time observations for P and S waves. In order to obtain satisfactory agreement with the entire data set we were required to take into account anelastic dispersion. The introduction of transverse isotropy into the outer 220 km of the mantle was required in order to satisfy the shorter period fundamental toroidal and spheroidal modes. This anisotropy also improved the fit of the larger data set. The horizontal and vertical velocities in the upper mantle differ by 2–4%, both for P and S waves. The mantle below 220 km is not required to be anisotropic. Mantle Rayleigh waves are surprisingly sensitive to compressional velocity in the upper mantle. High S_n velocities, low P_n velocities and a pronounced low-velocity zone are features of most global inversion models that are suppressed when anisotropy is allowed for in the inversion.
The Preliminary Reference Earth Model, PREM, and auxiliary tables showing fits to the data are presented.
We have identified the seismic phase PKJKP, traveling through the inner core of the Earth as a shear wave, in intermediate-period (2–10 s) records of the deep 1996 Flores Sea earthquake at eight stations of the French seismic network. This constitutes direct evidence of the solidity of the inner core which, while generally recognized, was until now only inferred from indirect evidence. The arrival times on stacked seismograms require a shear-wave velocity at the top of the inner core βICB=3.65 km/s in agreement with values suggested from normal mode observations. Julian et al.'s 1972 observation of a lower velocity (2.95 km/s) is easily reconciled with our result if interpreted as the surface reflection pPKJKP. The high Poisson ratio (ν=0.44) can be reconciled with a normal crystalline structure without invoking partial melting on account of the overwhelming pressure at the center of the Earth.
The core has often been suggested as a source for He presently found in the mantle. If the core served as the long-term storage reservoir for He in ocean island basalts with distinctively high 3He/4He ratios, then the difficulties of maintaining an isolated mantle reservoir separate from the source of mid-ocean ridge basalts are removed. However, the possibilities of trapping He into the core and releasing it into the overlying mantle have not yet been systematically evaluated. Here some of the factors to be considered are discussed. Appealing to the core as a source of rare gases necessarily evokes specific conditions of terrestrial rare gas acquisition and core formation, as well as core composition characteristics. It is shown that even if partition coefficients between silicates (solid or melt) and liquid Fe are low, there may have been sufficient gas present in the mantle during core segregation to supply a substantial quantity of He and Ne to the core. Transfer from the core to the mantle by either bulk entrainment of core material or chemical interaction at the core–mantle boundary may provide a reasonable mechanism for supplying relatively unfractionated rare gases to plumes. However, this remains speculative. While this process may have considerable impact on other trace elements, further limits on the rate of such transfer are only possible once further constraints are available on the concentration of other elements in the outer core. There are presently insufficient data available to establish whether or not the core is a plausible source of mantle He with high 3He/4He ratios. Therefore, further systematic investigation of this possibility should be conducted.
Seismological observations indicate that the inner core of the Earth is elastically anisotropic. Anisotropic structures are likely to be formed by dynamic processes and therefore such observations have the potential to provide constraints on flow in the inner core and on the geodynamo itself. But in addition to the difficulties in estimating the relevant physical properties of iron under inner-core conditions, even the macroscopic processes responsible for generating seismic anisotropy in this region have yet to be determined. As a result, the geodynamic significance of seismic anisotropy in the inner core has remained unknown. Here I propose-based on geodynamic and mineral physics considerations-that flow induced by the stress due to the magnetic field, the Maxwell stress, near the inner-core boundary produces an axisymmetric fabric responsible for the observed seismic anisotropy. The resultant seismic anisotropy reflects the geometry of the magnetic field near the inner-core boundary and therefore seismological observations might provide constraints on the geodynamo. This flow also causes non-uniform release of energy at the inner-core boundary, associated with solidification and melting which may affect the pattern of convection in the outer core.
The bulk properties of iron at the pressure and temperature conditions of Earth's core were determined by a method that combines first-principles and classical molecular dynamic simulations. The theory indicates that (i) the iron melting temperature at inner-core boundary (ICB) pressure (330 gigapascals) is 5400 (+/-400) kelvin; (ii) liquid iron at ICB conditions is about 6% denser than Earth's outer core; and (iii) the shear modulus of solid iron close to its melting line is 140 gigapascals, consistent with the seismic value for the inner core. These results reconcile melting temperature estimates based on sound velocity shock wave data with those based on diamond anvil cell experiments.
The seismological properties of the Earth's inner core have become of particular interest as we understand more about its composition and thermal state. Observations of anisotropy and velocity heterogeneity in the inner core are beginning to reveal how it has grown and whether it convects. The attenuation of seismic waves in the inner core is strong, and studies of seismic body waves have found that this high attenuation is consistent with either scattering or intrinsic attenuation. The outermost portion of the inner core has been inferred to possess layering and to be less anisotropic than at greater depths. Here we present observations of seismic waves scattered in the inner core which follow the expected arrival time of the body-wave reflection from the inner-core boundary. The amplitude of these scattered waves can be explained by stiffness variations of 1.2% with a scale length of 2 kilometres across the outermost 300 km of the inner core. These variations might be caused by variations in composition, by pods of partial melt in a mostly solid matrix or by variations in the orientation or strength of seismic anisotropy.
Elastic anisotropy in the Earth's inner core has been attributed to a preferred lattice orientation, which may be acquired during solidification of the inner core or developed subsequent to solidification as a result of plastic deformation. But solidification texturing alone cannot explain the observed depth dependence of anisotropy, and previous suggestions for possible deformation processes have all relied on radial flow, which is inhibited by thermal and chemical stratification. Here we investigate the development of anisotropy as the inner core deforms plastically under the influence of electromagnetic (Maxwell) shear stresses. We estimate the flow caused by a representative magnetic field using polycrystal plasticity simulations for epsilon-iron, where the imposed deformation is accommodated by basal and prismatic slip. We find that individual grains in an initially random polycrystal become preferentially oriented with their c axes parallel to the equatorial plane. This pattern is accentuated if deformation is accompanied by recrystallization. Using the single-crystal elastic properties of epsilon-iron at core pressure and temperature, we average over the simulated orientation distribution to obtain a pattern of elastic anisotropy which is similar to that observed seismologically.
A month-long observation of two horizontal ZnS(Ag) scintillating screens, 1 m^2 in area and located one above the other a certain distance apart, revealed about 10 correlated signals, whose time shift corresponds to an average velocity of only ~10-15 km/s. We assign the origin of these signals to the negative daemons, i.e. electrically charged Planckian particles, which supposedly form a part of the DM in the Galactic disk and were captured into the near-Earth orbits. The estimated flux of daemons is >=10^-4 m^-2 s^-1. The key part in the detection of daemons is played apparently by two processes: (i) the daemon shedding the captured heavy nucleus in a few tens of mks as a result of a relatively rapid decay of the daemon-containing nucleons, and (ii) emission of numerous Auger electrons and nuclear particles occurring in the next capture or recapture of a (heavier) nucleus by the daemon. Comment: 10 LaTeX pages, 1 EPS figure. This version contains an improved interpretation of the experimental data presented in the previous submission
Detection of negative daemons, DArk Electric Matter Objects, viz. Planckian supermassive (~2*10^-5 g) particles, whose population has been detected in March 2000 to populate near-Earth, almost circular, heliocentric orbits (NEACHOs), is being continued. The NEACHO objects hit the Earth with a velocity ~10-15 km/s. The results of these and new experiments (April-June, 2001) are now processed taking into account the scintillation shape depending on the magnitude and sign of the velocity of the daemons crossing our detector. The data accumulated during the time of the experiment and processed in this way reveal also the presence of (1) a high-velocity (~35-50 km/s) daemon population whose objects can be related to a population in the Galactic disk and/or that in strongly elongated, Earth-crossing heliocentric orbits (SEECHOs), as well as (2) a low-velocity (~3-10 km/s) population in geocentric Earth-surface-crossing orbits (GESCOs), whose objects traverse repeatedly the Earth to suffer a decrease in velocity by ~30-40% in a month in the process. An evolutionary relation between all these three (four?) populations is discussed. Assumptions concerning their manifestations in further observations are put forward. An analysis of possible interaction processes of daemons, which may have different velocities and directions of motion, with the detector components [ZnS(Ag) layers, 0.3-mm thick tinned-iron sheets etc.] on the atomic (emission of Auger electrons) and nuclear (nucleon evaporation from a nucleus excited in the capture and, subsequently, the decay of its protons) levels has permitted estimation of some characteristic times. In particular, the decay time of a daemon-containing proton is ~10^-6 s.
- V E Khain
V.E. Khain, Plate tectonics, in: The Mining Encyclopedia (Gornaya Encyclopediya), vol. 5, Publ. "Sov. Encyclopedia", Moscow, 1991, pp. 125-126 (in Russian).
- V P Trubitsyn
V.P. Trubitsyn, Fundamentals of the tectonics of floating continents, Izvestiya,
Physics of Solid Earth 9 (2000) 4-40.
- H Alfvén
- C.-G Fälthammar
- Cosmic Electrodynamics
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(2nd ed.), Clarendom Press, Oxford, 1967.
Dark Electric Matter Objects -new type of the Solar system population
- E M Drobyshevski
E.M. Drobyshevski, Dark Electric Matter Objects -new type of the Solar system
population, in: K.I. Churyumov (Ed.), 4th Usekhsvyatsky Readings. Modern
Problems of Physics and Dynamics of the Solar System, Kyiv T. Shevchenko
Natnl. Univ., Kyiv, 2001, pp. 102-113 (in Russian).