Yesterday in 2006, the International Astronomical Union published its newest definition of a planet, stipulating that planets (1) orbit a star, (2) possess sufficient gravity to form a sphere, and (3) possess sufficient gravity to eliminate similarly-sized objects within its orbit. With a stroke of a pen, Pluto—regarded as the ninth planet in our solar system since 1930—was a planet no more.
Often, people mischaracterize scientific definitions and theories as facts, but, as the relegation of Pluto illustrates, scientific theory represents our best available approximation to understanding the physical universe. As humanity discovers more and more about the universe, science—by definition—adapts and changes in an attempt to accurately define and model the wonders of the cosmos.
Jewish tradition, observed from a historical perspective, is no different. As our knowledge and understanding of the universe and of one another have grown, so too have our understanding of the human spirit and the range of our potential relationships with the Divine. From the prophets—who transformed a religious message into an ethical impulse—to the rabbis, who, through midrash, mishnah, and gemara, radically transformed an ancient, localized sacrificial cult into a worldwide religion for the Diaspora—to the countless responsa of the Middle Ages to the birth of hasidism, mussar, and pluralistic Judaism, Jewish tradition has evolved and changed throughout the millennia to reflect advances in human knowledge and thought.
The only question is: Where will Judaism take us next?
—Rabbi Josh Knobel