Daily Junction.mobi portalScience · May 18, 2026 · Dr. Nadia Okoro · 3 min
Since it began observing in 2022, the James Webb Space Telescope has reshaped our view of the early universe, distant galaxies and the atmospheres of other worlds. Here is a clear guide to how it works and what it has found.
When the James Webb Space Telescope released its first full-colour images in July 2022, they were more than pretty pictures. They were a signal that astronomy had a new instrument capable of seeing the universe in ways nothing before it could. In the years since, Webb has steadily rewritten parts of the textbook.
The James Webb Space Telescope (JWST) is the largest and most capable space observatory ever launched. It was built by NASA in partnership with the European Space Agency (ESA) and the Canadian Space Agency (CSA), and launched on 25 December 2021.
Its headline feature is a 6.5-metre primary mirror made of 18 gold-coated hexagonal segments — far larger than Hubble's 2.4-metre mirror. A bigger mirror gathers more light, and more light means fainter, more distant objects come into view.
Two design choices define what Webb can do.
It sees in infrared. Unlike Hubble, which works mostly in visible and ultraviolet light, Webb is optimised for infrared. This matters for two reasons:
It stays extremely cold. Infrared is essentially heat, so the telescope must be colder than the things it observes. Webb orbits near a location called the second Lagrange point (L2), about 1.5 million kilometres from Earth, and unfurls a five-layer sunshield the size of a tennis court. The shield keeps the Sun, Earth and Moon on one side, so the instruments on the other stay at around minus 230 degrees Celsius.
Webb is, in effect, a giant cold camera parked in the dark, designed to catch the faintest heat-glow of the distant cosmos.
One of Webb's most discussed findings is that galaxies in the very early universe appear more numerous, brighter and more mature than many models predicted. Astronomers have identified candidate galaxies whose light set out only a few hundred million years after the Big Bang. The existence of such well-developed galaxies so early is prompting a healthy rethink of how quickly structure formed.
Webb can analyse starlight that filters through the atmosphere of a planet as it passes in front of its star. By splitting that light into a spectrum, scientists can detect the chemical fingerprints of gases. Webb has detected molecules including carbon dioxide and water vapour in the atmospheres of planets beyond our solar system, opening a serious observational path toward studying potentially habitable worlds.
By looking through dust, Webb has produced extraordinarily detailed images of star-forming regions, capturing jets from newborn stars and the discs of material from which planets assemble. These observations help connect theory to what actually happens as solar systems take shape.
Closer to home, Webb has imaged planets, moons and rings in our own solar system with striking clarity, revealing features that ground-based telescopes struggle to resolve.
Every major leap in telescope capability has expanded what humanity can ask about its origins. Webb pushes the boundary of how far back in time we can look — toward the moment the first stars and galaxies switched on — while also turning its gaze on the question of whether other worlds might host the ingredients for life.
The telescope is designed to operate for many years, and its discoveries are still accelerating. The picture it is painting is one of a universe that assembled itself faster, and in richer detail, than we expected.
The James Webb Space Telescope is a cold, gold-mirrored infrared observatory parked far from Earth, and it has already deepened our understanding of the early universe and the atmospheres of distant planets. It is less a single discovery than a new pair of eyes — and we are only beginning to use them.
![[View image]](/img/james-webb-space-telescope-discoveries.jpg){kind=link}