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Nir Joseph Shaviv ((ヘブライ語:ניר יוסף שביב), born July 6, 1972) is an Israeli‐American physics professor, carrying out research in the fields of astrophysics and climate science. He is a professor at the Racah Institute of Physics of the Hebrew University of Jerusalem, of which he is now its chairman. He is best known for his solar and cosmic-ray hypothesis of climate change. In 2002, Shaviv hypothesised that passages through the Milky Way's spiral arms appear to have been the cause behind the major ice-ages over the past billion years. In his later work, co-authored by Jan Veizer, a low upper limit was placed on the climatic effect of .〔.〕 His best known contribution to the field of astrophysics was to demonstrate that the Eddington luminosity is not a strict limit, namely, that astrophysical objects can be brighter than the Eddington luminosity without blowing themselves apart. This is achieved through the development of a porous atmosphere that allows the radiation to escape while exerting little force on the gas. The theory was correctly used to explain the mass-loss in Eta Carinae's giant eruption, and the evolution of classical nova eruptions. Shaviv was interviewed for ''The Great Global Warming Swindle'' documentary. In the film he states: In 2012, he contributed, along with Werner Weber, Henrik Svensmark and Nicola Scafetta, to the book ''Die kalte Sonne. Warum die Klimakatastrophe nicht stattfindet'' (The Cold Sun) of Fritz Vahrenholt and Sebastian Lüning, a book expressing skepticism of anthropogenic global warming, which attracted considerable interest in Germany.〔Fritz Vahrenholt, Sebastian Lüning: ''Die kalte Sonne. Warum die Klimakatastrophe nicht stattfindet.'' Hoffmann und Campe, Hamburg 2012, ISBN 3-455-50250-4.〕 ==Cosmic Rays and Climate== Shaviv has been one of the proponents of a cosmic ray climate link. In 2003 he has shown that the cosmic ray flux over the past billion years can be reconstructed from the exposure ages of Iron meteorites, that these flux variations are expected from spiral arm passages, and they correlate with the appearance of ice age epochs on Earth. In a later work with Ján Veizer, it was demonstrated that the temperature reconstruction over the Phanerozoic correlates with the cosmic ray flux, but it does not correlate with the CO2 reconstruction, thus placing an upper limit on the effects of CO2.〔 This prompted several reactions by the climate community and rebuttals by Shaviv and his colleagues . He has also shown that the Cosmic Ray climate link explains part the faint sun paradox, since the slowly decreasing solar wind will give rise to a cooling effect that compensates the solar irradiance increase. Moreover, long term star formation activity in the Milky Way correlate with long term climate variations. In a more recent work with Andreas Prokoph and Ján Veizer, it was argued that the reconstructed temperature has a clear 32 million year oscillation that is consistent with the solar system’s motion perpendicular to the galactic plane. The oscillation also appears to have a secondary modulation consistent with the radial epicyclic motion of the solar system. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nir Shaviv」の詳細全文を読む スポンサード リンク
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