July 2015: CALGARY LAWN CHAIR BALLOONS

CalgaryLawnChair2015

On Sunday July 5th, while enjoying my time at the beach, Daniel Boria, age 26, was floating over the Calgary stampede grounds carried aloft  by 110 helium filled balloons while sitting in a lawn chair.
Our fascination with balloons goes back a long time, to Francisco Lana-Terzi [1631-1687] or maybe even earlier, to Giovanni Alfonso Borelli as decribed by that famous science (fiction) writer Isaac Asimov [1920-1992]:[1]

220px-Giovanni_Alfonso_Borelli

BORELLI,  Giovanni Alfonso
Italian mathematician and physiologist
Born: Naples, June 28, 1608
Died: Rome, December 31, 1679

“Borelli was a professor of mathematics and a friend of Galileo. His life, though not characterized by the controversies of his great friend, was not entirely smooth. In 1674 he had to leave Messina, the Sicilian city in which he was then teaching, and retire to Rome, where he remained under the protection of Chris­tina, former queen of Sweden. (This was the queen whose eccentric habits had brought on the death of Descartes [1596-1650]. She abdicted in 1654 and was received into the Roman Catholic Church the following year, after which she settled in Rome.)

Borelli corrected some of Galileo’s overconservation. Galileo [1564-1642] had neglected Kepler’s [1571-1630] elliptical or­bits, but now Horrocks [1618-1641] had extended them even to the moon, and Borelli rescued the ellipses, publici­zing and popularizing them.

He tried to extend the vague notions of Galileo and Kepler concerning the attractive forces between the sun and the planets, but was not successful. He tried also to account for the motion of Jupiter’s satellites by postulating an attractive force for Jupiter as well as for the sun. In this he (and Horrocks also at about this time) made a tentative step in the direction of universal gravitation, but the theory had to wait a generation for Newton [1642-1726].

Borelli suggested (under pseudonym) that comets tra­velled in parabolic orbits, passing through the solar system once and never returning. (The parabola, like the ellipse, was first studied by Apollonius [261-190 BC]. A parabola is an open curve something like a hairpin.) Any body following a parabolic path would approach the sun from infinite space, round it, and recede forever. Such an orbit would explain the erratic behavior of comets, without completely disrupting the orderliness of the universe.

Borelli understood the principle of the balloon, pointing out that a hollow copper sphere would be buoyant when evacuated, if it were thin enough, but that it would then collapse under air pressure.
It did not occur to him that collapse could be avoided if a lighter-than-air gas were used to fill the sphere as, in essence, the Montgolfier brothers [1740-1810 and 1745-1799] were to do a century and a half later.”
—————–
[1] Isac Asimov: Biographical Encoclopedia of Science and Technology (chronically ordered); 805 p. Avon Books, 1976

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