What is the James Webb Space Telescope?

James Webb Space Telescope, Credit : NASA

And why is everyone talking about it now? Astronomy enthusiasts have known about the James Webb Space Telescope since its construction began back in 2004. However, it wasn’t launched into space until the end of 2021.

On July 12th, 2022, NASA released the first images captured by this amazing telescope. And WOW, were they worth the wait…

This eight-burst Southern Ring nebula has a dying star in its center. Captured by James Webb Space Telescope. Credit: NASA

Table of Contents

What does the James Webb Space Telescope do?

On December 25th, 2021, the James Webb Space Telescope was launched into space, where it traveled one million miles away from Earth. Instead of orbiting Earth itself, it actually orbits within what is called a Lagrange Point, where the Sun and Earth’s gravitational forces overlap. These overlapping forces help maintain the James Webb Space Telescope’s position relative to earth and sun at a distance of about one million miles away from the Earth. Since arriving at a Lagrange Point, it has been using infrared light, which can’t be seen with the human eye, to image the wonders of our cosmos.

Webb will orbit the sun 1.5 million kilometers (1 million miles) away from the Earth at what is called the second Lagrange point or L2. (Note that these graphics are not to scale.) Credit NASA


The purposes of this immensely powerful telescope, which cost NASA 10 billion dollars to build, are four-fold. The first is to capture images of the first ever light in the universe. Wait, if the first light is from stars that are billions of years old, how can we image that? Since the universe is expanding, the distance between us and the origin of the first light increases, and it takes many, many light-years to reach us.

The second mission is to see how the galaxies were assembled in the early universe. It is thought that galaxies began forming within the first billion years after the Big Bang, or the beginning of the universe as we know it.

Thirdly, the James Webb Space Telescope was designed to view the birth of stars and planets. Before planets form, they are whirling clouds of gas or dust that condense over millions of years.

Last but not least, this technology can be used to take a closer look at individual planets both within and outside of our solar system. For those of you who have hopes that there may be life outside of our planet or solar system, you are in luck. We can now see if some of these planets harbor atmospheres that could support life, just like our atmosphere is the basis of survival for everything from the smallest single-celled organism to the largest blue whale!

Many scientists believe this is a very possible reality. So, stay tuned. It is a mystery what our science and history books may say in the next hundred years.

What is the telescope made of and how does it work?

The James Webb Space Telescope is the most powerful telescope constructed to date. On Earth, it is capable of focusing on the face of a U.S. penny from 25 miles away. From the Lagrange Point orbit, it can look at objects from over 13 billion light-years away!

To see this far in space, NASA needed to use numerous large mirrors to absorb a lot of light. In total, the James Webb is constructed with 18 hexagonal mirrors made with lightweight beryllium. These mirrors are foldable so that the telescope, which measures over 21 feet across, could fit inside of the rocket for takeoff.

The diameter of the James Webb mirror configuration is much larger than the eight-foot mirror diameter of the Hubble Telescope, the successor of the James Webb. The Hubble is still in operation today, orbiting just above Earth’s atmosphere. Although the two telescopes have key similarities, such as the use of mirrors, they look through space in very different ways. The Hubble Telescope primarily uses optical and ultraviolet wavelength technology, while James Webb relies on infrared. Infrared is necessary to look at a distant object in space. To see these objects clearly, one must see through increasingly long light wavelengths, a phenomenon called redshift. The gold coating on the James Webb mirrors was chosen because it enhances the mirrors’ reflection of infrared light.

JWST vs Webb
Webb mirror size 6.5m, Hubble mirror size 2.4m. Credit: NASA
The construction of the James Webb Space Telescope
The construction of the James Webb Space Telescope, Credit: NASA
JWST, Credit: NASA

What makes the James Web Space Telescope so special?

The fascination with our cosmos and our place within it can be traced back to early human history. Ancient Egyptians oriented their pyramids and temples toward the North because they believed that their pharaohs became stars after they transitioned to the afterlife. A biblical story details how the ancient Babylonians attempted to build a staircase that would reach the stars. Fast-forward 4,000 years to the first moon landing in 1969, an event that changed our world forever.

“That’s one small step for man, one giant leap for mankind” – Neil Armstrong, Apollo 11 Commander

Over 60 years later, we now have the James Webb Space Telescope, the largest and most powerful telescope ever created. It is like a cosmic time capsule that can transport us all the way back to the beginning. The beginning of time. With it, we are able to see galaxies that were born and have since died so that new galaxies could take their place. Just as paleontologists dig through bedrocks to learn about Earth’s history, astronomers can peer through telescopes to learn about our universe’s history.

NASA scientists celebrating the deployment of one of the telescope’s mirrors
NASA scientists celebrating the deployment of one of the telescope’s mirrors, Credit: NASA/Bill Ingalls


Atmosphere: the whole mass of air that surrounds a planet

Beryllium: a steel-gray metal whose chemical properties resemble aluminum

Big Bang: the beginning of the universe, which began as a single point and then expanded

Galaxy: a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction

Hubble Telescope: a space telescope that was launched into low Earth orbit in 1990 and remains in operation

Infrared: located outside of the visible spectrum at its red end

Lagrange Point: a point in space where a small object can remain in orbit due to the gravitational pull of two larger mass objects

Light-year: the distance that light travels in one year

Nebula: a giant cloud of dust and gas in space

Redshift: displacement of the spectrum of an astronomical object toward longer (red) wavelengths

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