In the early 1600s, a wondrous device was introduced in the Netherlands. It featured a tube with glass lenses at opposite ends and was designed for the purpose of making distant objects appear to be closer. Word of the invention, which would later be called the telescope, spread throughout Europe and came to the attention of Galileo Galilei, an Italian scientist. Although Galileo had not seen the device for himself, he became so intrigued with its potential that he designed and built one of his own.

A devout observer of the skies, Galileo intended to use his telescope to study the stars and planets. His model resembled a small pair of binoculars and used an arrangement of glass lenses for magnification. When he looked through it, objects appeared about thirty times larger than their normal size. In 1609 Galileo became the first person...