Jewels of discovery by NASA’s Webb Space Telescope in its first 3 years
To mark the three-year anniversary of Webb’s mission, NASA highlighted some of the discoveries and revelations by the most powerful space telescope operating today.
What is the James Webb Space Telescope?
According to NASA, the JWST sees the universe using infrared radiation, a form of light that we feel as heat and is invisible to human eyes.
Three years ago, NASA’s James Webb Space Telescope began its legendary mission unfolding the secrets of our universe and producing some of the most detailed images of celestial objects to date.
According to NASA, since July 2022, Webb has collected nearly 550 terabytes of data in just three years between its imaging and spectroscopy capabilities.
To mark the three-year anniversary of Webb’s mission, NASA highlighted some of the discoveries and revelations made by the most powerful space telescope operating today.
Let’s take a look at a few of Webb’s achievements that wow’d astronomers and the public alike.
Sizing up the aging universe
Webb was created to observe the "cosmic dawn," when the first stars and galaxies were forming. During this period, scientists theorized they would see a few faint galaxies, but Webb saw bright galaxies within 300 million years of the Big Bang.
The JADES Deep Field uses observations taken by NASA’s James Webb Space Telescope as part of the JADES (JWST Advanced Deep Extragalactic Survey) program. A team of astronomers studying JADES data identified about 80 objects that changed in brightness over time. Most of these objects, known as transients, are the result of exploding stars or supernovae. Prior to this survey, only a handful of supernovae had been found above a redshift of 2, which corresponds to when the universe was only 3.3 billion years old — just 25% of its current age.
(NASA, ESA, CSA, STScI, JADES Collaboration / NASA)
"Hundreds of millions of years might not seem quick for a growth spurt, but keep in mind that the universe formed in the big bang roughly 13.8 billion years ago," NASA said. "If you were to cram all of cosmic time into one year, the most distant of these galaxies would have matured within the first couple of weeks, rapidly forming multiple generations of stars and enriching the universe with the elements we see today."
Webb data backs up 'Hubble Tension'
JWST was used to cross-check the physics problem known as "Hubble Tension," which refers to Hubble Space Telescope observations over 30 years that show the universe is expanding faster than expected. The mystery phenomenon of why the universe is expanding is known to cosmologists as "dark energy."
A representation of the evolution of the universe over 13.77 billion years. The far left depicts the earliest moment we can now probe, when a period of "inflation" produced a burst of exponential growth in the universe. For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe.
(NASA's Goddard Spaceflight Center)
According to the team behind the 2024 study, observations from both Hubble and JWST aligned closely. With Webb’s findings, cosmologists say it might be time to rethink the standard cosmological model and begin looking for something yet to be discovered that could improve our understanding of the universe.
JWST reveals source of Saturn's ring system
Scientists used the James Webb Space Telescope to take their first-ever direct look at how the water emissions from the Moon Enceladus supply the Saturnian system and its famed rings. Webb revealed the plume from Enceladus spans more than 6,000 miles, about 20 times wider than the Moon, spreading out into donut-shaped rings encircling Saturn.
The icy crust at the south pole of Enceladus exhibits large fissures that allow water from the subsurface ocean to spray into space as geysers, forming a plume of icy particles. NASA's Cassini spacecraft captured this imagery in 2009.
(NASA/JPL-Caltech/Space Science Institute / NASA)
OCEAN ON SATURN’S MOON ENCELADUS HAS ALL THE INGREDIENTS FOR LIFE, STUDY FINDS
Can planets survive the death of a star?
When a star like our Sun dies, the death creates ripple effects large enough to consume any nearby planets. In a final act, the outer layer of the star is shed, leaving behind a super-hot core known as a white dwarf.
Scientists used Webb's Mid-Infrared Instrument to find potential surviving planets orbiting white dwarfs. If confirmed, it would mean under the right conditions, a planet could survive the death of its star.
False-color image of WD 0310–688 (bluish-white star in the center) using three James Webb Space Telescope Mid-Infrared Imaging bands. Other lights in the field include distant galaxies, background stars and potential exoplanets.
(NASA / NASA)
Details of spiral galaxies down to ‘the smallest scale’
NASA’s James Webb Space Telescope delivered incredibly detailed images of spiral galaxies in a combination of near- and mid-infrared light. According to NASA, these images reveal so much more than previous Hubble Space Telescope images, down to the filaments of dust wrapping around the spiral arms.
Click through the gallery below to see Webb's images of spiral galaxy NGC 628 compared to Hubble's.
![Spiral galaxy NGC 628 is 32 million light-years away in the constellation Pisces. Webb’s image of NGC 628 shows a densely populated face-on spiral galaxy anchored by its central region, which has a light blue haze that takes up about a quarter of the view. In this circular core is the brightest blue area. Within the core are populations of older stars, represented by many pinpoints of blue light. Spiny spiral arms made of stars, gas, and dust also start at the center, largely starting in the wider area of the blue haze. The spiral arms extend to the edges, rotating counterclockwise. The spiraling filamentary structure looks somewhat like a cross section of a nautilus shell. The arms of the galaxy are largely orange, ranging from dark to bright orange. Scattered across the packed scene are some additional bright blue pinpoints of light, which are stars spread throughout the galaxy. In areas where there is less orange, it is darker, and some dark regions look more circular. A prominent dark]()
Image 1 of 3Spiral galaxy NGC 628 is 32 million light-years away in the constellation Pisces. Webb’s image of NGC 628 shows a densely populated face-on spiral galaxy anchored by its central region, which has a light blue haze that takes up about a quarter of the view. In this circular core is the brightest blue area. Within the core are populations of older stars, represented by many pinpoints of blue light. Spiny spiral arms made of stars, gas, and dust also start at the center, largely starting in the wider area of the blue haze. The spiral arms extend to the edges, rotating counterclockwise. The spiraling filamentary structure looks somewhat like a cross section of a nautilus shell. (NASA, ESA, CSA, STScI, Janice Lee (STScI), Thomas Williams (Oxford), and the PHANGS team)
![Hubble’s image of NGC 628 shows a densely populated face-on spiral galaxy anchored by its central region, which has a light yellow haze that takes up about a quarter of the view. The core is brightest at the center, washing out light from other objects. Delicate spiral arms start near the center and extend to the edges, rotating counterclockwise. There is more brown dust beginning at the center, but as the arms extend outward, brown dust lanes alternate with diffuse lines of bright blue stars. Throughout the spiral arms, there are bright pink patches of star-forming clusters.]()
Image 2 of 3Hubble’s image of NGC 628 shows a densely populated face-on spiral galaxy anchored by its central region, which has a light yellow haze that takes up about a quarter of the view. The core is brightest at the center, washing out light from other objects. Delicate spiral arms start near the center and extend to the edges, rotating counterclockwise. There is more brown dust beginning at the center, but as the arms extend outward, brown dust lanes alternate with diffuse lines of bright blue stars. Throughout the spiral arms, there are bright pink patches of star-forming clusters. (NASA, STScI)
![Face-on spiral galaxy, NGC 628, is split diagonally in this image: The James Webb Space Telescope’s observations appear at top left, and the Hubble Space Telescope’s on bottom right.]()
Image 3 of 3Face-on spiral galaxy, NGC 628, is split diagonally in this image: The James Webb Space Telescope’s observations appear at top left, and the Hubble Space Telescope’s on bottom right. (NASA, ESA, CSA, STScI, Janice Lee (STScI), Thomas Williams (Oxford), and the PHANGS team)
"Webb’s new images are extraordinary," said Janice Lee, a project scientist for strategic initiatives at the Space Telescope Science Institute in January 2024. "They’re mind-blowing even for researchers who have studied these same galaxies for decades. Bubbles and filaments are resolved down to the smallest scales ever observed, and tell a story about the star formation cycle."
JWST sizes up asteroid 2024 YR4
More recently, Webb’s powerful instruments were used to size up a newly discovered asteroid potentially threatening Earth.
Asteroid 2024 YR4 was discovered on Dec. 27, 2024, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Río Hurtado, Chile. The asteroid warranted international attention, briefly jumping to the highest asteroid threat on the Torino Impact Hazard Scale.
CHANCES ASTEROID 2024 YR4 WILL HIT MOON INCREASE BUT EARTH REMAINS IN THE CLEAR
JWST was able to help scientists determine asteroid 2024 YR4 is about the size of a 15-story building, calculate its orbital path and declare Earth safe from a collision course with the asteroid. However, the Moon is still not out of the woods yet.
On March 26, 2025, NASA’s James Webb Space Telescope captured images of asteroid 2024 YR4 that indicate the asteroid is about the size of a 15-story building. Researchers also say the asteroid’s surface may be dominated by rocks that are maybe fist-sized or larger. Asteroid 2024 YR4 is smallest object targeted by Webb to date.
(NASA, ESA, CSA, STScI, Andy Rivkin (APL) / NASA)
NASA estimates the Webb telescope has about 20 more years of observation time left, allowing for decades of discoveries to come.