At age 46, Galileo was no young kid in 1610. But events that year forever changed his life – and our take on the universe. They involved the colossal planet Jupiter, which right now is at its closest and brightest of the next four years.
This story actually started two years earlier, when a Dutch eyeglass-maker created the first telescope. When Galileo heard about it, he was one of the few who could duplicate the instrument sight unseen. Galileo soon demonstrated his instrument to a Venice merchants’ group, who flipped over its possibilities at spotting returning ships ahead of everyone else. Everyone wanted one. Then Galileo turned his telescope to the sky.
Bam! The Moon – regarded since ancient Greek times as a smooth body with oceans – was now visibly pockmarked with mountains and craters. The Sun had spots – and rotated once a month! The Milky Way’s creamy glow burst into untold separate stars. Wonder upon wonder.
He wrote, “I have observed the nature and material of the Milky Way. With the aid of the telescope this has been scrutinized so directly and with such ocular certainty that all the disputes that have vexed philosophers through so many ages have been resolved, and we are at last freed from wordy debates about it. The Galaxy is, in fact, nothing but a congeries of innumerable stars grouped together in clusters.”
Other observers soon proved Galileo correct (except for that naive idea that the world would now be free of wordy debates). But it was Jupiter, shining brilliantly in Taurus the Bull, that proved the most amazing and controversial. On January 7, 1610, Galileo saw three stars lined up alongside the dazzling planet. By the 13th he had watched them change position each night, spotted a fourth as well and realized that they were orbiting around that world.
This, 405 years ago, was no small thing. At the time, Church doctrine followed the writings of Aristotle and Ptolemy and insisted that Earth is the center of all motion. For some bizarre reason, they’d made it into a religious principle. So Galileo saw no benefits after he published his startling discoveries. Instead they brought him up on charges, forced him to recant at penalty of being burned at the stake and left him to die penniless.
But fast-forward to our modern times, and Jupiter is now orbited by a marvelous spacecraft that bears the name Galileo. Those four giant moons are now called “the Galilean satellites.” So it all worked out for the bearded, cantankerous Italian – or at least for his disembodied spirit.
With any cheap telescope, you can duplicate Galileo’s discoveries. There isn’t a better month to watch Jupiter than now. You’ll see those four moons and horizontal black-and-yellow belts and zones on the planet itself, like the stripes on a bee. Jupiter is out all night long, in the constellation Leo. But you don’t need to know that; just find the brightest star in the sky anytime after 8 p.m.
Preview: Between 6 and 7 p.m., that’s Venus shining so brightly in the west above the sunset point. Next Friday (the 20th), be sure to watch the dramatic three-way conjunction of the crescent Moon, Venus and dim orange Mars. Don’t miss it.