Watcher of the Skies

Manjit Kumar in The Telegraph:

Galileo-m_1733576f It is a little known fact that in 1532 Copernicus’s sun-centred solar system was presented to an audience in the Vatican. Given the storm that was to come, it is barely believable that the then pope, Leo X, afterwards sent a note of encouragement to Copernicus as the Polish priest laboured to finish his book. On the Revolutions of the Heavenly Spheres was published in 1543 and Copernicus, so the story goes, held the first copy to come off the press just hours before he died. As long as his heliocentric model was presented as hypothetical, the Vatican was unconcerned by Copernicanism. One man changed all that.Born in February 1564, Galileo Galilei initially set out to be a doctor before switching to mathematics – much to the displeasure of his father. It is unlikely that, according to the legend, he ever dropped balls from the leaning tower of Pisa as he investigated the motion of falling bodies and discovered that all objects fall at the same rate, contradicting what everybody believed since Aristotle.

When, in 1609, he learnt of the invention of the telescope by a Dutch spectacle maker, Galileo quickly constructed his own. Within a matter of months he had transformed it from a toy into an instrument of scientific discovery and he found that the Milky Way was not a streak across the sky but a multitude of stars; that the Moon had mountains and valleys; and he observed the phases of Venus and the spots on the Sun. 'For Galileo, seeing was believing,’ says the historian David Wootton. Yet he argues persuasively in this well researched, intellectual biography that Galileo was a Copernican long before his discovery of the moons of Jupiter proved that not all heavenly bodies revolved around the Earth. In March 1610, Galileo published his discoveries in the aptly titled book, The Starry Messenger. All 550 copies were sold within a week and soon the 46 year-old was Europe’s most celebrated natural philosopher.

More here.