In a global reenactment of humankind's first magnified look at the heavens 400 years ago, hundreds of thousands of telescopes across the Earth will turn this Saturday night, April 4, in unison to the night sky to gaze at the Moon and a gleaming planet Saturn.
Four hundred years ago this year, Galileo Galilei first used the newly-invented telescope to peer at the Moon with a level of detail that had not previously been possible, and with that simple act, flung open a window on a new era in our understanding of the cosmos and our place within it.
In celebration of Galileo's seminal achievement, the year 2009 has been recognized as the International Year of Astronomy. A special feature of this celebration is the global event that extends from April 2 to April 5, called "100 Hours of Astronomy", and culminates on the night of April 4 as hundreds of thousands of people are expected to gather around telescopes and gaze at the heavens together. Saturn will be prominently placed in the sky and will be a main object of observation.
But unlike the place that Galileo sighted centuries ago, something about the ringed planet this time will be very different. This time, one intrepid robotic explorer, sent from an alien world clear across the solar system, will be among the myriad bodies that accompany Saturn in its eternal motion across the heavens ... a machine, too small to be visible to Earth-based observers, that has nonetheless irrevocably and forever altered our view of this majestic planetary system.
Cassini has been orbiting Saturn since 2004 and, at our command, has returned hundreds of thousands of glorious, exquisitely detailed vistas of the planet and its spectacular rings and moons. As a result, on the night of April 4, people gathered around telescopes around the globe will gaze upon a planet that humankind has now, four hundred years on, come to know intimately.
As our contribution to the International Year of Astronomy, and in honor of Galileo, we have collected together, here on this website , some of the most moving, magnificent and scientifically significant images, movies and discoveries that have been acquired by Cassini's high resolution cameras over the last five years.
Those of you who break from your normal routine on Saturday night to gaze up at Saturn would be wise to remember to gaze also upon this collection of sights. Let yourself be reminded how bold and daring and far-reaching we were to even imagine that one day we would cross the vast distances separating the planets to revel in what is found there, and how extraordinary we really are for actually having done it.
Carolyn Porco Cassini Imaging Team Leader CICLOPS Boulder, CO