India, June 9 -- The most anticipated public offering in modern financial history will not simply be another stock market event. When SpaceX goes public, investors will be buying into something far older than a rocket company. They will be buying into a dream that is old as time immemorial, beginning centuries before stock exchanges, venture capital, or even modern science itself.

The dream is simple: To leave the Earth.

For most of human history, the heavens were a realm of myth and mystery. The stars guided sailors and inspired poets, but they remained fundamentally unreachable. Then, in 1609, Galileo Galilei, an Italian professor of physics and mathematics in Padua pointed a simple telescope towards the sky.

What Galileo saw changed...