Edwin Hubble

The history of astronomy is a history of receding horizons. Knowledge has advanced in great surges, generated by new methods of investigation. Each surge has carried understanding to a new level from which the universe is observed in growing detail and over an ever-widening range.

Equipped with his five senses, man explores the universe around him and calls the adventure Science. With increasing distance our knowledge fades, and fades rapidly. Eventually we reach the dim boundary—the utmost limits of our telescopes. There, we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial.