has been one of the biggest catalysts for science over the past 500 years,

Interestingly, it wasn't scientific interest, but more practical matters that led to the initial advancements in optics,

starting around 1440 when Johannes Gutenberg invented his printing press.

In short order, books, which had been a rarity,

were now becoming a widespread phenomenon.

All that new reading material meant more knowledge was circulating,

but it also meant that more people were straining their eyes,

likely as they read by candlelight.

And while spectacles had been invented in Italy around 1286,

the need for reading glasses increased substantially.

Now that people could use lenses to see things more clearly,

they started wondering if vision could be enhanced to see things the human eye couldn't perceive by its own devices.

Robert Hooke pursued microscopy, and 1665 he published his findings of worlds inside worlds,

which he called "cells" in the book "Micrographia."

At the other end of the spectrum,

Galileo innovated with telescopic lenses,

and in 1609, he had refined a telescope until he had an instrument powerful enough to see distant objects in the sky

with an accuracy no one had before him.

He found that the moon had craters and mountains,

that Jupiter had moons of its own, and the whole system governing the earth and space was brought into question.

Not everyone was thrilled with all the things Galileo saw though.

For instance, it was taught at the time that the moon was a perfectly smooth sphere.

Yet here was visual proof that was awfully hard to discount.

Upon finding moons around Jupiter, he also verified what Johannes Kepler had surmised:

that the earth was not the center of the universe,

dispelling another central dogma of Galileo's day.

Then almost exactly a year after Galileo died,

Isaac Newton was born.

A lot that had been unknown was visible by now,

but much of it was simply the foundation for further questions.

What was light anyway? And color, for that matter?

What were the laws that governed the earth, and the heavens?

And could we capture them through keen observation?

Newton experimented extensively with optics,

and came to understand light as something of substance,

and colors as components of light at different frequencies.

Before Newton, people widely believed that the color was due to different amounts of light,

with red being lots of light, and blue being mostly dark.

Newton's prism experiments showed that white light could not only be broken into its component colors with one prism,

but that a second lens could recompose those colors back into white light again,

thus showing that color was a matter of light's refraction rather than how light or dark it was.

Newton's studies of optics led to the development of the reflecting telescope.

This, together with his study of planetary motion, led to his theory of gravitation,

one of the world's greatest examples of learning to see something invisible

by observing its effect on things that are visible.

So fast forward a few hundred years, and here we stand.

We've evolved from a single lens to optics that reveal the birth of a star in another galaxy,

or a child developing in the womb,

or an electron whirling around an atom.

At a time when so much is visible, how we see the world around us matters even more than what we see.

Will we see a world where everything important has already been discovered?

Or will we see one in which yesterday's discoveries are but a doorway to the breakthroughs of tomorrow?