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  • 1
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    Unbekannt
    Oxford : Periodicals Archive Online (PAO)
    The British journal for the philosophy of science. 5:19 (1954:Nov.) 203 
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Earth, moon and planets 18 (1978), S. 327-337 
    ISSN: 1573-0794
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Ovenden's hypothesis suggesting former existence of a planet of 90 Earth masses which supposedly filled the Titius-Bode gap in the asteroid belt and then suddenly disappeared 16 million years ago, is critically examined by the morphological method. It is shown that an explosive removal, however improbable, could have led to the formation of the asteroids from a non-explosive core (the nuclear charge being placed outside of it), but that life on Earth would have been completely destroyed by three successive blasts-one from the direct impact of the ejecta of the planet, another from the increased radiation suddenly emitted by the Sun when hit by the ejecta, and a third one (arriving, however, first) from the radiation emitted by the nuclear explosion. The geological record of the continuity of Life on Earth for the past 109 years definitely excludes the possibility of such an explosion in the late Tertiary. The other mode of removal of the planet-in a gravitational encounter with an intruder either from interstellar space or from the unexplored outskirts of the solar system, under the condition of not having disturbed the existing regularity of planetary orbits-is not only extremely improbable, to be expected once during 100 million times the age of the solar system; but it would leave no asteroids behind, all of the previously existing primaeval asteroids having been rapidly eliminated in encounters with the hypothetical planet. Whatever the merits of Ovenden's long-range calculations of the secular perturbations of coplanar ‘circularized’ planetary orbits, the hypothesis of a massive planet to have existed in the asteroidal region and then recently to have suddenly disappeared, belongs to the realm of the impossible. After such a hypothetical event, either we would not be here on Earth, or there would be no asteroids in their present place between Jupiter and Mars.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 21 (1973), S. 307-398 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A morphological study of the physical and dynamical processes of planet formation is presented, with emphasis on the intermediary role of comet nuclei. Although guided by a particular model of the evolution of the pre-planetary solar nebula, implying the freezing-out of hydrogen in the region of the giant planets, the derivations and conclusions are of wider import, applicable to other cosmogonic models as well as to certain phases of star formation. The items evaluated physically, dynamically, or statistically comprise: (1) the total number mass of comets in Oort's cloud; (2) a re-evaluation of the diameters and masses of cometary nuclei; (3) the processes of nucleation from gravitational and ‘Boltzmann’ instabilities of gaseous media to agglomerations of particulate matter as conditioned by inbuilt angular momentum; (4) the statistical-dynamical conditions and time scales of orbital interaction of comets with the planets and the consequences of disintegration. A consistent model proposes the formation of comets and planets in pre-planetary rings of the residual solar nebula, with subsequent ejection, chiefly by Jupiter, of the comets to Oort's sphere. Screening by absorbing matter is not only probable, but necessary to protect the comets from dis-integration during the process of ejection.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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