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  • Optics, or the enhancement of our natural vision,

  • 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?

Optics, or the enhancement of our natural vision,

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B1 TED-Ed newton galileo johannes prism visible

【TED-Ed】The story behind your glasses - Eva Timothy

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    keep seeing posted on 2014/05/12
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