NOVA

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Narrator

The James Webb Space Telescope. It is the largest, most innovative space telescope ever built. Designed to peer deep into the universe, to solve some of astronomy's greatest cosmological mysteries. One of the amazing things about telescopes is that they are literally time machines. They allow us to see the universe as it was in the distant past. -

Narrator

Light travels in waves at 186,000 miles per second. Light that's emitted from the sun takes eight minutes to reach us. So if we go outside and you look at the sun, you're really seeing the sun eight minutes ago. You can imagine just further stepping out in the universe. The nearest star to us is four light years away. That means light has taken four years to arrive to us. -

Narrator

The nearest galaxies are tens of thousands of light years away, so we are seeing these galaxies not as they are today, but as they were tens of thousands of years ago. Because we are actually able to see in the past by looking at distant galaxies, because that light left so long ago, we're seeing them as they were in the past. -

Narrator

As astronomers scoured the Hubble deep fields, they noticed something strange. We began to see little orange dots, these little smudges. These red, faint objects, they looked different. They were redder, they were amorphous, they looked like jellyfish. Those were really the farthest galaxies the Hubble has ever observed, that humans have ever observed. -

Narrator

The farther away a galaxy is, the redder it appears to our telescopes. This strange phenomenon is called redshift. What's happening in the universe is it's expanding and pulling space apart as it goes, and it's stretching the light in the same way. When an object is moving towards us, the light waves gets smushed, and shorter light waves are bluer. As an object moves away, the light waves get essentially stretched, and longer wave lengths are red. And so when we're talking about galaxies in the distant universe, they're all moving away from us, and so in essence, their light is stretched redder and redder. Now, the more distant galaxies, they are far enough away that their light has been stretched all the way out of the visible part of the spectrum and into the infrared. -

Narrator

The instruments onboard Hubble can see some of those infrared waves. Hubble has done amazing stuff, but it has found its limitation. -

Narrator

JWST is designed to see a lot more, further into the infrared part of the spectrum, and further back in time. JWST will push that window open. It will just completely revolutionize our way of seeing the universe. People will be simply blown away, because they will not be able to recognize what they see.