It took an object the size of a basketball to change the world. On October 4, 1957, the Soviet Union set in motion events that would culminate in Sunita Williams' awe-inspiring, record-breaking walk in space.

The object in question was called Sputnik I, the world's first artificial satellite weighing a mere 183 pounds (about 83 kgs). It became the first manmade object to orbit our planet on its elliptical path. It captured the world's attention, made the American public nervous, and marked the start of not just the US-USSR space race, but also mankind's entry into the space age.

Over the decades that followed, scientific developments continued to bridge the gap between Earth and the heavens, clearing away the clouds and illuminating what had, until then, been an area of darkness.