Wednesday, November 5, 2008

Galileo's New Toy

The night of 7 January, 1610, in Padua, Venetian Republic, a 45-year-old mathematics professor opened his window and peered at the sky through an optical instrument he had built some six months earlier. This professor´s name was Galileo Galilei and the instrument was the telescope, known at the time as a "spyglass."
By the time Galileo came across the spyglass in 1609 the instrument had been known for some time as a peculiar toy sold in marketplaces in the Netherlands, France and England. Nobody knows who invented it. It is most likely one of those inventions that "are in the air" and which several people hit upon serendipitously and almost simultaneously. One Hans Lippershey, spectacle-maker from Middelburg, had applied for a patent to the States General of the Netherlands and tried to sell the instrument to the government by pointing out its possible military applications.
Galileo was a skillful constructor of scientific instruments, and once he had seen a spyglass he was quick to grasp the principles involved. He immediately set to work on an instrument which made distant objects appear to be three times closer than they really were. Some time later, he pushed contemporary technology to the limit by building a telescope ten times as powerful as the first one.
Realizing, as Lippershey had, the strategic potential of the spyglass, Galileo subsequently arranged a demonstration for the Venetian authorities. Later he wrote:
"Very many were the patricians and senators who, although aged, have more than once climbed the stairs of the highest campanili of Venice, to detect sails and vessels on the sea, so far away that coming under full sail toward the harbor, two hours or more passed before they could be seen without my spyglass."
As a consequence of this demonstration, Galileo´s salary was doubled and he was granted a lifelong professorial appointment at Padua.
Six months later, Galileo took his best telescope and trained it on the night sky. It was a stroke of genius. Today, one can hardly think of anything more natural to do with a telescope than to point it at the sky, but we must remember that at the time, although Nicolaus Copernicus had published his views about a sun-centered cosmos more than 60 years before, the sky was still held to be divine and pristine, a place of purity as opposed to earthly corruption. Many centuries before, Aristotle claimed that the stars and planets, including the sun and moon, were celestial emmanations that moved around the earth attached to crystal spheres and surrounded by a transparent substance called aether. Looking at the sky, therefore, meant peering into the abode of God. Galileo was treading unchartered and dangerous territory.
What he saw with his telescope during the Winter of 1610 confirmed what he had known for a long time, but had been cautious not to maintain openly --that Aristotle had been dead wrong about the nature of the stars and planets. The moon did not have a polished surface, as the Greek philosopher had said, but was instead deeply scarred with craters, crevasses and mountains, like the earth. The telescope revealed countless stars that were not visible to the unaided eye, and showed that Venus has phases like the moon, which is only possible if it orbits the sun and not the earth. But what stunned him the most was the discovery of four previously undetected "stars" in the vicinity of Jupiter. It gradually became clear that they were circling the planet. This demolished an old objection to the Copernican system in which the earth moved around the sun like the wandering stars, namely, that the moon could not possibly revolve around the earth if the earth itself revolved around the sun.
Galileo´s telescopic findings, which he wasted no time in publishing, changed humankind´s picture of the universe.

Tuesday, June 3, 2008

Darwin's Nose

The course of history rarely hinges on the impact of a single individual...let alone an individual’s nose. Yet Charles Darwin’s nose --which one captain Robert FitzRoy disliked at first sight-- was a hair’s breadth from disqualifying its owner for the post of “naturalist” aboard HMS Beagle, departing on a voyage around the world. The young Darwin had been recommended for the job by his mentor, professor John Steves Henslow, after several candidates had turned down FitzRoy’s overtures.

Charles’ father, Dr. Robert Darwin II, was a respected physician, the son of another doctor Darwin, Erasmus, who at the close of the 18th century had proposed one of the many theories of evolution then in vogue. The ponderous and imposing doctor Robert wanted his son to follow in his footsteps, but Charles gave up medicine after witnessing an operation performed without the aid of anesthetics. In the wake of this incident, doctor Darwin had decided that his son should become a clergyman. This decision seemed to suit the indolent Charles, and so he set off to Cambridge University.

Charles Darwin had some time earlier began collecting insects spurred by his cousin William Darwin Fox. The new hobby soon became an obsession. “I am dying by inches, from not having anybody to talk to about insects,” he wrote to his cousin.

Charles sought after new beetle varieties. He was more interested in collecting as many different kinds as he could get his hands on than in dissecting and classifying them. “I will give proof of my zeal,” he wrote in his autobiography.
One day, tearing off some old bark, I saw two rare beetles and seized one in each hand, then I saw a third and new kind, which I could not bear to lose, so that I popped the one which I held in my right hand into my mouth. Alas! It ejected some intensely acrid fluid which burnt my tongue so that I was forced to spit the beetle out, which was lost, as was the third one.

It was at Cambridge that Darwin, aged 22, met the botanist J. S. Henslow. Henslow, a revered teacher, developed a great fondness for his pupil. “What a fellow that Darwin is for asking questions,” he once remarked. Chalres, his mind still set on a career in the Church of England, had finally found a passion.

One day, returning home from a walking tour of North Wales with the geologist Adam Sedgwick, Charles found a letter from Henslow waiting for him. Her Majesty’s Ship Beagle, commanded by captain Robert FitzRoy, was soon to set sail for South America on a scientific voyage that would eventually take her around the world. “Capt. F. wants a man (I understand) more as a companion than a mere collector and would not take any one, however good a naturalist, who was not recommended to him likewise as a gentleman,” wrote Henslow.

FitzRoy was rather cold on his first meeting with Darwin. Charles was a bourgeois from a liberal family, whereas the captain was an aristocrat and a headstrong conservative. FitzRoy felt particularly hostile toward the young man’s nose. It was not the nose of a man who could withstand the hardships of life at sea. But in the end Charles’ enthusiasm and good nature won the seaman over and he was given the position.

And so Charles Darwin embarked in what was to be a five year trip around the world, during which his early belief that species were immutable was to be shaken and eventually shattered, to be replaced by the conviction that they had evolved through the ages. Twenty-odd years after Darwin’s return to England, the naturalist poured the results of his musings in a beautiful book that changed the world --The Origin of Species.