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- Joseph-Alphonse Adhémar (* 1797; † 1862) war ein französischer Mathematiker. Adhémar schlug als erster astronomische Ursachen, nämlich die Exzentrizität der Erdbahn um die Sonne, für die Entstehung der Eiszeiten vor (Révolutions de la mer. Déluges périodiques). Unter dem Titel Cours de mathématiques à l’usage de l’ingénieur civil verfasste er eine Anzahl von Spezialhandbüchern über verschiedene Teile der reinen und angewandten Mathematik. Ferner schrieb er einige Abhandlungen über darstellende Geometrie. (de)
- Joseph Alphonse Adhémar (1797–1862) was a French mathematician. He was the first to suggest that ice ages were controlled by astronomical forces in his 1842 book Revolutions of the Sea. The Earth's orbit is elliptical, with the Sun at one focus; lines drawn through the summer and winter solstice; and the spring and autumn equinox; intersect with the sun at right angles. The Earth is closest to the Sun (perihelion) near the northern hemisphere winter solstice. The earth moves faster through its orbit when closer to the sun. Hence, the period from the northern hemisphere's autumn equinox to winter and spring is shorter by around seven days than the period from spring to summer to autumn; the reverse is true in the southern hemisphere. Hence, northern hemisphere winter is shorter. Because of this, Adhemar reasoned that because the southern hemisphere had more hours of darkness in winter, it must be cooling, and attributed the Antarctic ice sheet to this. Adhemar knew of the 22,000 year cycle of precession of the equinoxes, and theorised that the ice ages occurred in this cycle. One immediate objection to the theory was that the total insolation during a year does not vary at all during the precessional cycle, only its seasonal distribution. Another was that the timing was wrong; however this could not be tested by observations available at the time. Adhemar's theory was further developed, first by James Croll and later by Milutin Milanković. Adhemar predicted the Antarctic ice sheet and theorised about its thickness by comparing the depths of the Arctic and circum-Antarctic oceans. Finding the Antarctic oceans deeper (the measurements he used may not have been fully representative) and attributing this to the gravitational attraction of the Antarctic ice sheet, he postulated a truly enormous ice sheet approximately 90 km thick. (en)
- Joseph-Alphonse Adhémar (1797 - 1862) est un professeur et mathématicien français. (fr)
- Joseph-Alphonse Adhémar (Parigi, febbraio 1797 – Parigi, 1862) è stato un matematico e ingegnere francese. Fu autore di libri di scienze e del primo progetto di ferrovie di circonvallazione, che ideò per un'eventuale difesa di Parigi. (it)
- Alphonse Joseph Adhemar (Paris, 1797 — 1862) foi um matemático francês. Idealizou a hipótese da periodicidade dos períodos glaciares. (pt)
- Альфо́нс Жозе́ф Адема́р (фр. Adémar, 1797—1862) — французский математик. Написал много элементарных руководств по различным отраслям математики: «Cours de mathém. à l’usage de l’ingénieur civil» (Париж, 1832), «Traité de géométrie descriptive» (1834, 1847) «Traité de la coupe des pierres» (1837), "Traité de perspective linéaire (1838), «Traité des ombres». На русский язык переведено его сочинение «Возмущение моря, или Периодичность всемирных потопов» (СПб., 1871). (ru)
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- Joseph-Alphonse Adhémar (* 1797; † 1862) war ein französischer Mathematiker. Adhémar schlug als erster astronomische Ursachen, nämlich die Exzentrizität der Erdbahn um die Sonne, für die Entstehung der Eiszeiten vor (Révolutions de la mer. Déluges périodiques). Unter dem Titel Cours de mathématiques à l’usage de l’ingénieur civil verfasste er eine Anzahl von Spezialhandbüchern über verschiedene Teile der reinen und angewandten Mathematik. Ferner schrieb er einige Abhandlungen über darstellende Geometrie. (de)
- Joseph-Alphonse Adhémar (1797 - 1862) est un professeur et mathématicien français. (fr)
- Joseph-Alphonse Adhémar (Parigi, febbraio 1797 – Parigi, 1862) è stato un matematico e ingegnere francese. Fu autore di libri di scienze e del primo progetto di ferrovie di circonvallazione, che ideò per un'eventuale difesa di Parigi. (it)
- Alphonse Joseph Adhemar (Paris, 1797 — 1862) foi um matemático francês. Idealizou a hipótese da periodicidade dos períodos glaciares. (pt)
- Альфо́нс Жозе́ф Адема́р (фр. Adémar, 1797—1862) — французский математик. Написал много элементарных руководств по различным отраслям математики: «Cours de mathém. à l’usage de l’ingénieur civil» (Париж, 1832), «Traité de géométrie descriptive» (1834, 1847) «Traité de la coupe des pierres» (1837), "Traité de perspective linéaire (1838), «Traité des ombres». На русский язык переведено его сочинение «Возмущение моря, или Периодичность всемирных потопов» (СПб., 1871). (ru)
- Joseph Alphonse Adhémar (1797–1862) was a French mathematician. He was the first to suggest that ice ages were controlled by astronomical forces in his 1842 book Revolutions of the Sea. The Earth's orbit is elliptical, with the Sun at one focus; lines drawn through the summer and winter solstice; and the spring and autumn equinox; intersect with the sun at right angles. The Earth is closest to the Sun (perihelion) near the northern hemisphere winter solstice. The earth moves faster through its orbit when closer to the sun. Hence, the period from the northern hemisphere's autumn equinox to winter and spring is shorter by around seven days than the period from spring to summer to autumn; the reverse is true in the southern hemisphere. Hence, northern hemisphere winter is shorter. (en)
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- Joseph-Alphonse Adhémar (de)
- Joseph-Alphonse Adhémar (fr)
- Joseph-Alphonse Adhémar (it)
- Joseph Adhémar (en)
- Alphonse Joseph Adhemar (pt)
- Адемар, Альфонс Жозеф (ru)
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