The James Webb Space Telescope: Our Incredible Eye on the Infrared Universe

From distant galaxies born shortly after the Big Bang to the atmospheres of worlds orbiting other stars, the James Webb Space Telescope is revealing parts of the universe that were previously hidden from view.

Its enormous golden mirror, tennis-court-sized sunshield and extraordinary sensitivity make Webb look and sound like something from science fiction. Yet since beginning science operations in 2022, it has been sending back real observations that are reshaping our understanding of space.

So, what makes the James Webb Space Telescope so special—and what has it discovered so far?

What Is the James Webb Space Telescope?

The James Webb Space Telescope, often shortened to JWST or simply Webb, is the largest and most complex observatory ever sent into space.

It is an international project involving NASA, the European Space Agency and the Canadian Space Agency. Webb launched aboard an Ariane 5 rocket on Christmas Day 2021 before beginning a carefully controlled journey into deep space.

Unlike an ordinary telescope, Webb is not designed to be looked through. Its scientific instruments collect infrared light and send their data back to Earth, where astronomers turn those measurements into images, spectra and other valuable information.

Webb’s main scientific goals include investigating:

• The first stars and galaxies

• How galaxies change over time

• The birth of stars and planetary systems

• Planets within our own Solar System

• Exoplanets orbiting other stars

• The ingredients needed for potentially habitable worlds

In short, Webb is helping us explore where we came from—and whether environments capable of supporting life might exist elsewhere.

Why Is Webb’s Mirror Gold?

Webb’s most recognisable feature is its enormous golden primary mirror.

The mirror measures 6.5 metres across and is made from 18 hexagonal segments. These separate pieces work together as one precisely aligned surface, collecting extremely faint light from distant objects.

The segments are made primarily from beryllium, a strong but lightweight material that remains stable in extremely cold conditions. Each segment is covered with a microscopically thin layer of gold because gold reflects infrared light particularly well.

Despite its appearance, the mirror does not contain a huge amount of gold. The coating is incredibly thin—but it is thick enough to help Webb gather infrared radiation with remarkable efficiency.

Why Does Webb Observe Infrared Light?

Human eyes can detect only a small portion of the electromagnetic spectrum known as visible light. Infrared light has longer wavelengths that our eyes cannot see, although we often experience some forms of infrared radiation as heat.

Observing in infrared allows Webb to do several extraordinary things.

It Can Peer Through Cosmic Dust

Stars and planets are often born inside dense clouds of gas and dust. These clouds can block visible light, hiding what is happening inside them.

Infrared wavelengths can pass through some of this dust, allowing Webb to reveal young stars, planet-forming discs and other objects that would otherwise remain concealed.

It Can Study the Early Universe

As the universe expands, light travelling across it becomes stretched towards longer, redder wavelengths. This process is known as redshift.

Light that originally left a very distant galaxy as visible or ultraviolet radiation may reach us as infrared light after travelling for billions of years. Webb’s infrared instruments therefore allow it to detect extremely distant galaxies and investigate some of the earliest periods in cosmic history.

Learn more about this remarkable effect in our guide to looking back in time through space.

It Can Analyse Exoplanet Atmospheres

When a planet passes in front of its star, a small amount of the star’s light travels through the planet’s atmosphere. Different gases absorb particular wavelengths, leaving a chemical fingerprint in the light.

Webb can separate that light into a spectrum and search for substances such as water vapour, carbon dioxide and methane.

Detecting one of these gases does not automatically mean that life has been found. However, studying combinations of chemicals can tell astronomers an enormous amount about a planet’s atmosphere, temperature and possible environment.

Webb Had to Fold Up to Fit Inside Its Rocket

Webb’s mirror and sunshield were far too large to fit inside a rocket at their full size. Engineers therefore designed the observatory to fold for launch.

Once in space, Webb completed a complicated series of deployments. Its solar array, antenna, sunshield, secondary mirror and primary mirror wings all had to unfold in the correct sequence.

Hundreds of mechanisms needed to operate successfully. Many of these actions could not be repeated if something went wrong.

The deployment took around two weeks, while the complete journey, cooling, alignment and commissioning process took several months. It was one of the most ambitious engineering operations ever attempted in space.

Webb’s Sunshield Is About the Size of a Tennis Court

Infrared telescopes must be kept extremely cold. If Webb became too warm, heat from the observatory itself could overwhelm the faint infrared signals it is trying to detect.

Its five-layer sunshield blocks heat and light from the Sun, Earth and Moon. Each layer is extremely thin, and spaces between the layers allow heat to escape.

This creates two very different sides of the observatory:

• A warm side facing the Sun, containing the solar panel and communications equipment

• A cold side carrying the mirror and scientific instruments

Webb’s Mid-Infrared Instrument, known as MIRI, must operate at a temperature close to -266°C. A specialised cooling system keeps it even colder than the rest of the observatory.

Where Is the James Webb Space Telescope?

Webb is approximately 1.5 million kilometres from Earth, operating around a region called the second Sun–Earth Lagrange point, or L2.

At L2, the gravitational effects of the Sun and Earth combine with the telescope’s motion in a useful way. This allows Webb to remain in a relatively stable position with the Sun, Earth and Moon always on the same side of its sunshield.

Webb does not sit perfectly still at L2. It follows a large orbit around this region while travelling around the Sun alongside Earth.

This location provides the cold, stable observing conditions Webb needs—but it also places the telescope far beyond the reach of current crewed servicing missions.

Is Webb Replacing the Hubble Space Telescope?

Webb is frequently described as Hubble’s successor, but it is not a direct replacement.

The two observatories are designed to study different, although overlapping, parts of the electromagnetic spectrum. Hubble observes primarily visible and ultraviolet light, with some near-infrared capability. Webb concentrates mainly on near- and mid-infrared wavelengths.

This means they can examine the same object in different ways.

Hubble might reveal brilliant stars and glowing gas, while Webb can peer through surrounding dust or detect cooler material. Observations from both telescopes can be combined with data from X-ray and radio observatories to create a more complete understanding of an object.

Rather than competing, the observatories complement one another.

What Has Webb Discovered?

Webb has already observed targets ranging from nearby asteroids to galaxies billions of light-years away.

Surprisingly Early Galaxies

Webb has identified and confirmed galaxies that existed only a few hundred million years after the Big Bang.

Some early galaxies appear brighter, larger or more developed than astronomers initially expected. This does not mean the Big Bang has been disproved, as some misleading headlines have suggested. Instead, it is helping scientists refine models of how quickly the first stars and galaxies formed.

Webb has also found compact, distant objects nicknamed “little red dots”. Their exact nature remains an active area of research, but many may be connected with rapidly feeding supermassive black holes during an unusual period of galactic development.

Hidden Stellar Nurseries

Webb has produced remarkably detailed views of regions where stars are being born, including the Carina Nebula, the Orion Nebula and the famous Pillars of Creation.

Infrared observations allow astronomers to see through layers of dust and locate young stars that were previously difficult or impossible to detect.

These spectacular images are beautiful, but they also contain valuable information about how stars gather material, produce powerful winds and influence their surroundings.

Exoplanet Atmospheres

Webb has detected carbon dioxide in an exoplanet atmosphere and measured substances including water vapour, methane and sulphur dioxide on worlds beyond our Solar System.

It has also studied extremely hot gas giants, rocky worlds and planets with thick, hazy atmospheres.

Webb has not discovered confirmed alien life. What it has demonstrated is the ability to investigate distant atmospheres with a level of detail that was previously out of reach.

New Worlds and Solar System Discoveries

Webb does not spend all its time staring towards the edge of the observable universe.

It has studied Mars, Jupiter, Saturn, Uranus and Neptune, producing infrared views that reveal clouds, rings, auroras and atmospheric features. It has also observed moons, comets, asteroids and distant objects beyond Neptune.

In 2025, Webb observations revealed a previously unknown moon orbiting Uranus. In July 2026, astronomers also announced that Webb had detected a hidden giant exoplanet in the closely studied Beta Pictoris system.

These discoveries demonstrate that even familiar cosmic neighbourhoods can still contain surprises.

Explore the worlds closer to home in our Planet Profiles series.

Are Webb’s Images the Colours We Would See?

Webb primarily detects infrared wavelengths that human eyes cannot see. Its images therefore need to be translated into visible colours.

Scientists and image-processing specialists assign colours to different infrared filters. Shorter infrared wavelengths are generally represented with bluer colours, while longer wavelengths appear redder.

This process is not simply adding random colour to make the images attractive. It helps distinguish different wavelengths, materials, temperatures and physical processes.

The result allows us to interpret invisible information in a form our eyes can understand.

Those sharp, eight-pointed stars often seen in Webb images are also real features of the telescope’s design. They are diffraction spikes created as light interacts with the hexagonal mirror segments and supports holding the secondary mirror.

Can You See the James Webb Space Telescope From Earth?

Webb is far too distant and faint to be seen with the unaided eye, binoculars or an ordinary garden telescope.

Exceptionally well-equipped observers have managed to image it as a tiny moving point using large telescopes and specialised equipment, but it will never look like its famous golden-mirrored form from Earth.

Fortunately, you do not need Webb to begin exploring the universe.

Many of the objects photographed by Webb—including planets, star-forming nebulae, star clusters and galaxies—can also be observed from a dark location with amateur equipment. They will not show the same colour or detail, but seeing one with your own eyes can be every bit as memorable.

Our guide to what you can see with a telescope is a great place to start. You can also explore our range of telescopes and astronomy binoculars for your own adventures beneath the night sky.

Explore the James Webb Space Telescope

Want to follow Webb’s discoveries or explore its remarkable images for yourself? These official resources are excellent places to continue your journey.

The Agencies Behind Webb

The James Webb Space Telescope is an international partnership involving three major space agencies:

• NASA’s James Webb Space Telescope website – Explore the mission, its latest discoveries, science objectives and official news.

• European Space Agency: Webb – Discover ESA’s contribution to Webb, including the launch aboard Ariane 5 and its involvement with the NIRSpec and MIRI instruments.

• Canadian Space Agency: James Webb Space Telescope – Learn about Canada’s Fine Guidance Sensor and NIRISS scientific instrument, alongside news, activities and educational material.

Webb’s science and mission operations are conducted by the Space Telescope Science Institute, which also helps process and share the observatory’s scientific data and imagery.

See Webb’s Latest Images

Visit the official Webb image gallery to explore spectacular observations of nebulae, galaxies, planets, stars and other astronomical objects.

Many images can be downloaded in different resolutions, while the accompanying information explains what Webb observed and which instruments were used.

You can also learn how Webb’s full-colour images are created. Because Webb observes infrared wavelengths that our eyes cannot see, its data must be carefully translated into visible colours.

What Is Webb Observing Right Now?

The interactive What Is Webb Observing? tool shows Webb’s current, recent and upcoming scientific targets.

You can explore which instrument is being used, where the target lies in the sky and whether the observation relates to galaxies, exoplanets, star formation or our own Solar System.

Remember that Webb can observe several targets during a single day, and its data may take months—or even years—to be fully analysed and published.

Learn More About Webb

For answers to common questions about the telescope, its orbit, instruments and capabilities, visit the official Webb frequently asked questions.

Families, schools and younger astronomers can also explore Webb-themed activities and learning resources, including printable activities, interactive features, models and educational material.

If you would like something for the wall of a classroom or budding astronomer’s bedroom, NASA also provides a collection of free Webb posters and printables.

The Beginning of a New Era

The James Webb Space Telescope was designed to answer some of astronomy’s biggest questions, but its observations are also uncovering mysteries nobody expected.

How did the earliest galaxies grow so quickly? What can distant atmospheres tell us about their planets? How common are planetary systems like our own? Could the chemical conditions required for life exist elsewhere?

Webb may help us answer some of these questions. It will almost certainly give us many new ones.

That is the joy of astronomy: every time we find a clearer view of the universe, we discover that there is even more waiting beyond it.