Engineering The James Webb Space Telescope

On July 12, 2022, NASA unveiled new images from the James Webb Space Telescope. To the untrained eye, they just look like beautiful photos, but to astronomers, they mark a groundbreaking turn in space exploration. So, what is JWST, how does it work, and what’s in those new images? Here’s a simple explanation:

What is the James Webb Space Telescope, and where is it?

Artist's impression of the James Webb Space Telescope

“Artist’s impression of the James Webb Space Telescope.” Courtesy of ESA/ATG medialab.

The James Webb Space Telescope (JWST) is a giant telescope that NASA launched December 25, 2021. Right now, it’s orbiting the Sun about one million miles from Earth.

 

How does the James Webb Space Telescope work?

"Diagram of the James Webb Space Telescope’s Main Components"

“Diagram of the James Webb Space Telescope’s Main Components.” Courtesy of NASA, ESA, CSA, Joyce Kang (STScI)

To put it simply, JWST uses a giant mirror (the giant honeycomb pattern on the telescope) and a complex camera to capture infrared light and help us study space.

When people say JWST can see back in time, they’re not exaggerating. Light travels quickly through space, but there’s a lot of space to get through. So when JWST sees light, it’s seeing what the light looked like when it began traveling to JWST.

Light travels about 186,000 miles per second, 11.16 million miles per minute (one light-minute), and 5.88 trillion miles per year (one light-year). The Sun is about 93 million miles from Earth, or 0.0000158 light-years. So, when you see sunlight here on Earth, that light took about eight minutes to get to you. Essentially, you’re seeing what the Sun looked like about eight minutes ago (don’t look directly at it!)

That’s an extremely short distance compared to how far JWST can see. While we can see light that’s from 0.0000158 light-years away, i.e., from eight minutes ago, JWST can see light waves that have traveled from 13.6 billion light-years away, or from billions of years ago. With JWST, we can see billions of years into the past.

 

Why is the James Webb Space Telescope important?

When we can see so far away in space and so far back in time, we can study what the universe looked like billions of years ago, and we’ll have more clues about how the universe has changed over time. We can also see if there’s evidence of habitable planets and/or other life.

 

How is the James Webb Space Telescope different from the Hubble Space Telescope?

JWST lets us see deeper into the universe than we’ve ever seen. See how JWST’s photos compare to the Hubble Telescope’s.

"This illustration shows both the NASA/ESA Hubble Space Telescope and the NASA/ESA/CSA James Webb Space Telescope and compares their respective mirrors. The main mirror of Hubble has a diameter of 2.4 metres, the foldable main mirror of James Webb is even 6.5 metres in diameter."

“This illustration shows both the NASA/ESA Hubble Space Telescope and the NASA/ESA/CSA James Webb Space Telescope and compares their respective mirrors. The main mirror of Hubble has a diameter of 2.4 metres, the foldable main mirror of James Webb is even 6.5 metres in diameter.” Courtesy of ESA/M. Kornmesser.

What are in the first images from the James Webb Space Telescope?

Image 1: Deep Field: SMACS 0723

Image from the James Webb Space Telescope of a deep field. Thousands of galaxies can be seen on a black canvas.

Image courtesy of NASA, ESA, CSA, and STScI

This image shows thousands of galaxies from 4.6 billion light-years away (i.e., from 4.6 billion years ago). A galaxy contains billions of stars, and those stars have their own solar systems, and those solar systems have their own planets. That’s a lot of planets to explore!

The craziest part? From our view, it’s all the size of a grain of sand. According to NASA, “If you held a grain of sand up to the sky at arm’s length, that tiny speck is the size of Webb’s view in this image.”

Image 2: Exoplanet: WASP-96 B

This shows an exoplanet’s spectroscopy as it passed in front of a star. An exoplanet is a planet that orbits around a sun other than our own, and spectroscopy is how we measure light, radiation, and particles as they interact with matter.

The data from this distant planet’s spectroscopy shows evidence of water.

A chart showing an exoplanet’s spectroscopy measurements, taken from the James Webb Space Telescope

Image courtesy of NASA, ESA, CSA, and STScI

Image 3: Stellar Death: Planetary Nebula NGC 3132

Image from the James Webb Space Telescope of a nebula. A star is in the very center, surrounded by a blue, misshapen circle. Clouds of red and orange surround the bubble, and surrounding the clouds is a black, starry canvas

Image courtesy of NASA, ESA, CSA, and STScI

Here we see a nebula, a cloud of gas and dust, that’s coming out of a dying star’s explosion. According to NASA, the star in the center of the image, “has been sending out rings of gas and dust for thousands of years in all directions.”

Image 4: Interacting Galaxies: Stephan’s Quintet

Image courtesy of NASA, ESA, CSA, and STScI

You may have seen Stephan’s Quintet in “It’s a Wonderful Life.” It’s a group of five galaxies, with stars being born and even outward flows from a black hole. This is Webb’s largest image: 150 million+ pixels.

Image 5: Star Forming Region: NGC 3324 In Carina Nebula

Image from the James Webb Space Telescope of a star forming region in Carina Nebula. The bottom 75% of the image is orange clouds that look like cliffs and mountains. In the top 25% is a blue and black canvas with stars and other white specs.

Image courtesy of NASA, ESA, CSA, and STScI

This image shows never-before-seen stars. The “Cosmic Cliffs” at the bottom are actually the edge of a gaseous cavity that came from a nebula, which was emitted by the young stars at the top of the image (sometimes nebulae come from a star’s birth and not its death).

Want more? Click here to see more images and data from NASA, ESA, CSA, and STScI.

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Kelly Obbie

Social Media Coordinator at CADENAS PARTsolutions | A 2018 graduate of The Media School at Indiana University, Kelly studied journalism, public relations, English and Spanish and has experience in news writing and editing as well as social media writing and management. She also has professional and personal experience in videography and photography. She currently lives in Ohio but has lived in four states, and in her free time, she enjoys running, hiking, learning languages, and watching Disney movies.