Name: Why James Webb’s Infrared Vision is a Gamechanger
Uploaded: 2021-10-13T17:40:06.000Z
Duration: 4 min 40 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

When you look up at the night sky, you're only seeing a tiny fraction of the estimated

septillion stars out there in the universe…and honestly it's not your fault. Even astronomers

have a hard time. But now the James Webb Space Telescope may

just make things a lot easier and push the very limits of infrared light observation

to travel back over 13 billion years ago for a glimpse of our universe's first light.

So first, what exactly is infrared light? Well, we can't see it, but we can feel it

as heat. On the electromagnetic spectrum, Infrared

lies right outside of the visible light section, as longer, redder wavelengths. You've probably

seen infrared light used in remote controls and even temperature guns commonly found during

the COVID-19 pandemic. But for astronomy, infrared light seems to

excel in revealing the unseen. Since the beginning of the universe, physical

space has been in a constant state of expansion. Although stars and galaxies both keep their

size, the shape and space between them continues to expand.

And as light travels through the ever growing reaches of space, it is stretched to longer

and longer wavelengths. So some of these wavelengths we as humans can actually see,

as long as it falls along the visible light region, in what's known as our “window

of visibility”. Any wavelength extended beyond or falling

short of that region is effectively invisible to us.

And because of the estimated age of the universe, most of the light from our oldest stars actually

lies beyond the visible region since it has been constantly expanding for billions of

years. This is known as Cosmological Redshift. Infrared technology allows us to look back

to these oldest stars, all thanks to the unique ability of longer wavelengths to pass through

dense clouds of cosmic dust. Shorter wavelengths are usually blocked by these clouds, hindering

astronomers' studies of the universe. And this new technology exposed infinite possibilities

of study. Even encouraging the launch of the first infrared observatory in 1983, the Infrared

Astronomical Satellite, which completed a full infrared survey of the sky. And by 1998

had helped usher in the identification of hundreds of thousands of new objects which

were previously unseen. This led to other infrared discoveries like the largest ring

around Saturn and identifying one of the furthest supermassive black holes ever discovered.

Now astronomers and engineers are pushing this science to the limit once again with

the highly anticipated Webb telescope. The observatory hosts four scientific instruments

and two detectors on board, allowing it to study near-infrared and mid-infrared wavelengths.

The Near-infrared camera hosts on-board  coronagraphs

that can hone in on very faint objects  even if they

are near extremely bright lights, similar to how you would hold your hand up in front

of the sun to see another object. Then there's the Near-Infrared Spectrograph, which has

a unique technology to analyze the spectrum of an object using a micro-shutter array.

This contains 100 microshutter cells, measuring as wide as a human hair. This technology reveals

physical properties of a target including chemical composition, mass, and temperature.

Next up is the Mid-Infrared Instrument which will use its on board cameras and you guessed

it, mid-infrared light to provide amazing imagery, even more impressive than that of

the Hubble Space Telescope. And finally the Fine Guidance Sensor/Near InfraRed Imager

and Slitless Spectrograph will accurately find targets, investigate exoplanets, and

detect first light within star systems. Using these instruments, Webb's goal is to observe

early light in the universe over 13 billion years ago, essentially peering back in time

to help piece together how the universe shifted from a state of helium and hydrogen to the

complex worlds we see today. And what's really cool is that it's a

huge international collaboration between NASA, European Space Agency and the Canadian Space

Agency. This next generation observatory is a nod

to our endless curiosity as human beings to know more about how it all began. So now the

fun part begins and I can't wait to see how our hard work has paid off when we get

those first images back... So what are some of your biggest questions

about the Webb telescope? Let us know in the comments below and make sure to subscribe. Thanks for

watching Seeker and I'll see you next time.