Convulsions

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Aurora borealis

Mt. Baker, Washington

green and blue colored night sky

Photographer Wade B. Clark, Jr., © 2000. 35mm Canon F1 set on a tripod, 28mm wide angle f1.8 lens, Fuji NHG II 800 speed color print film, and about a 20-second exposure using a cable release.

Aurora borealis of August 11-12, 2000, over Mount Baker, east of Bellingham, Washington, viewed from Baker Lake. Near the horizon is the Big Dipper (part of the constellation Ursa Major, The Great Bear), in upper right is part of the Little Dipper (part of the constellation Ursa Minor, The Little Bear), and in the center (just above the Big Dipper) and upper left is part of the constellation Draco (The Dragon).

Jefferson ordered for Meriwether Lewis a two-volume reference work commonly called Owen's Dictionary. It wasn't the latest, and it was British, but it was the best available.1 Beginning with "Aurora borealis is an extraordinary meteor, shewing itself in the night-time, in the northern parts of the heavens," Owen's went on to describe the northern lights' appearance as:

an apparent, though not real cloud . . . terminated with one or more lucid arches, and sometimes by a long bright streak of light, lying parallel to the horizon. . . .

Out of these arches proceed streams of light generally perpendicular to the horizon, but sometimes a little inclined to it, and very much resembling the tail of comets. . . .

The upper ends of the streams appear and vanish incessantly, which causes such a seeming trembling in the air, that you would think the upper part of the heavens to be as it were in convulsions.2

The writer summarized four current theories, beginning with that of astronomer Edmond Halley,3 who thought that the Northern Lights came from a type of friction in the atmosphere:

. . . magnetic effluvia which he supposes enter the earth near the south pole, and pervading its pores, pass out again at the same distance from the northern; and thinks, that . . . they may be capable of producing a small degree of light, either from the greater density of the matter, or from the greater velocity of its motion . . . .

Monsieur de Marain4 endeavours to prove that it is owing to the zodiacal light, or the atmosphere of the sun, which mixing with our atmosphere, and being of an heterogeneous nature, produces the several appearances of the aurora borealis.

Mr. Maier,5 of the academy at Petersburg, accounts for it from exhalations fermenting and taking fire in the atmosphere of the sun, which mixing with our atmosphere, and being of an heterogeneous nature, produces the several appearances of the aurora borealis.

Mr. Rowning6 gives a very ingenious and natural solution of all the above phaenomena, from such effluvia as are continually exhaled from the surface and bowels of the earth.

Comet-predictor Halley was furthest from the truth, in this case, since the "effluvia" don't go into one side of earth"s atmosphere and out the other. Marain came closest to what we now understand.

It seems that the writer thought that the aurora borealis was a new heavenly phenomenon, but that's only because climate had intervened for some years before their time, in the form of the Little Ice Age.

 

1. Donald Jackson, "Some Books Carried by Lewis and Clark," Missouri Historical Society Bulletin, Vo. XVI, No. 1 (October, 1959), 4-13.

2. A New and Complete Dictionary of Arts and Sciences; comprehending all the branches of useful knowledge, with accurate descriptions as well of the various Machines, instruments, tools, figures, and schemes necessary for illustrating them, as of the classes, kinds, preparations, and uses of natural productions, whether animals, vegetables, minerals, fossils, or fluids; together with the kingdoms, provinces, cities, towns, and other remarkable places throughout the world. Illustrated with above three hundred copper-plates, curiously engraved by Mr. Jeffreys, geographer and engraver to his Royal Highness the prince of Wales. The whole extracted from the best authors in all languages, by a Society of Gentlemen. London: Printed for W. Owen, at Homer's Head, in Fleet-street. MDCCLIV. s.v. "Aurora Borealis."

3. Edmond Halley (1656-1742), English astronomer and mathematician, who in 1705 calculated the orbit of the comet that still bears his name—Halley's Comet, which last was visible from earth in 1986, follows a seventy-six-year orbit, and thus will be seen next in 2062. See Calvin J. Hamilton, "Halley's Comet," at www.solarviews.com/eng/halley.htm (accessed March 2003).

4. Jean Jacques Dortous de Mairan (1678-1771), French astronomer and author of Dissertation sur les variations du barometre, Beziers: E. Barbut, 1715.

5. Mr. Maier is not identifiable. The Academy of Sciences, St. Petersburg, Russia, was founded by Peter the Great in 1724 and opened the following year; today it is The Russian Academy of Sciences. During the 1700s, foreign scientists were frequently invited to work there.

6. Rowning may be John Rowning (1701-1771), author of A Compendious System of Natural Philosophy, London: S. Harding, 1744; 8th edition, 2 vols. London: Printed for J.F. and C. Rivington, 1779.