What has JWST discovered?

JWST’s biggest discoveries are the most distant galaxies ever confirmed, a surprising abundance of bright galaxies and black holes in the early universe, and the first detailed chemistry of exoplanet atmospheres. Since its first images in July 2022, the James Webb Space Telescope has also checked the Hubble tension, imaged a new planet and traced ices that build planets. Here are the major results through October 2026.

JWST is one of several observatories in our guide to space telescopes and observatories; for how it compares with its predecessor, see JWST vs Hubble.

JWST’s biggest discoveries at a glance

Year	Discovery	Why it matters
2022	First images, including the SMACS 0723 deep field	Showed JWST performing better than required
2022	Carbon dioxide on the exoplanet WASP-39b	First definitive CO2 in an exoplanet atmosphere
2023	Ices in a dark molecular cloud	The frozen ingredients of planets, mapped
2023	TRAPPIST-1 b and c lack thick atmospheres	First tests of rocky planets around red dwarfs
2023	Carbon-rich dust within a billion years of the Big Bang	Dust formed earlier than expected
2023 to 2024	Black holes in GN-z11 and UHZ1	Supermassive black holes grew very early
2024	Neutron star evidence inside SN 1987A	The remnant of a famous supernova found
2024	JADES-GS-z14-0 at redshift 14.32	A bright galaxy 300 million years after the Big Bang
2024	A “dead” galaxy at redshift 7.3	Star formation shut down surprisingly early
2024 to 2025	Hubble tension checks with JWST distances	Ruled out a simple measurement error
2025	TWA 7 b, a planet discovered by JWST imaging	The lightest planet imaged directly at the time
2025 to 2026	MoM-z14 at redshift 14.44	Current record for the most distant galaxy
2024 to 2026	Little red dots as buried young black holes	A new population of early objects

1. The first images (July 2022)

JWST’s first deep field, of the galaxy cluster SMACS 0723, was released on July 11, 2022, followed the next day by images of the Carina Nebula, Stephan’s Quintet, the Southern Ring Nebula and a spectrum of the exoplanet WASP-96 b. The commissioning report showed the telescope exceeded its requirements almost across the board (Rigby et al. 2023).

2. The most distant galaxies

JWST was built to find the first galaxies, and it has pushed the frontier back to about 280 million years after the Big Bang.

• JADES-GS-z14-0 (2024). The JADES team confirmed a galaxy at redshift 14.32 and another at 13.90, about 300 million years after the Big Bang (Carniani et al. 2024).
• MoM-z14 (2025 to 2026). A team led by Rohan Naidu reported MoM-z14 at redshift 14.44, about 280 million years after the Big Bang, the current record as of October 2026, announced by ESA/Webb on January 28, 2026.

The surprise was not just distance but brightness. Early galaxies are more numerous and luminous than many models predicted, prompting the “too bright, too early” debate. In 2023 Ivo Labbé and colleagues flagged red candidate galaxies that seemed too massive for their age (Labbé et al. 2023); follow-up showed some are actually growing black holes. This is not a crisis for the Big Bang, but it is forcing faster recipes for early star formation. More in our galaxies guide.

JWST also found a galaxy at redshift 7.3 that had already stopped forming stars, a “dead” galaxy only about 700 million years after the Big Bang (Looser et al., Nature, 2024), and carbon-rich dust grains at redshifts up to about 7 (Witstok et al., Nature, 2023).

3. Early black holes and little red dots

JWST revealed that supermassive black holes were already large and hungry in the young universe.

• GN-z11 (2024). A black hole of about 1.6 million solar masses feeding vigorously at redshift 10.6, about 430 million years after the Big Bang (Maiolino et al. 2024).
• UHZ1 (2023). Combined JWST and Chandra X-ray data revealed a black hole at redshift about 10.1 that seems to have started heavy, supporting the idea that some black holes are born from collapsing gas clouds rather than stars (Bogdán et al., Nature Astronomy, 2024).
• Little red dots. JWST found large numbers of compact, very red objects in the first billion or two years. A January 2026 Nature paper argued they are young supermassive black holes inside dense cocoons of ionized gas, which would make them about 100 times less massive than first estimated. Other interpretations remain in play. See our explainer on little red dots.

4. Exoplanet atmospheres

JWST reads the chemistry of exoplanet air by splitting the starlight that filters through it.

• WASP-39b (2022). The first definitive detection of carbon dioxide in an exoplanet atmosphere, at 26 sigma (JWST’s WASP-39b result).
• Rocky planets (2023 to 2025). TRAPPIST-1 b and c show no thick atmospheres; TRAPPIST-1 d lacks an Earth-like one; TRAPPIST-1 e may or may not have a nitrogen atmosphere. Details in the most Earth-like exoplanets.
• K2-18b (2023 to 2025). Methane and carbon dioxide on a temperate sub-Neptune, then a disputed 2025 claim of a possible biosignature gas that independent reanalyses did not support (K2-18b).
• TWA 7 b (2025). JWST’s coronagraph imaged a planet of about 0.3 Jupiter masses in the debris disk of a young star, the first planet discovered through JWST imaging (Lagrange et al., Nature, June 2025).

5. The Hubble tension

JWST was used to test whether the “Hubble tension”, the disagreement between the expansion rate measured locally and predicted from the early universe, comes from measurement errors. Adam Riess’s SH0ES team used JWST’s sharper infrared view to rule out crowding of Cepheid stars as the cause at high confidence and found a value near 73 km/s/Mpc, as in their Hubble work (SH0ES 2022). Wendy Freedman’s team, using other kinds of stars, found about 70 km/s/Mpc. The tension is not resolved.

6. Stars, ices and the solar system

• Ices (2023). JWST mapped frozen water, carbon dioxide, ammonia, methane and other molecules in a dark cloud in Chamaeleon I, the raw materials of planets (McClure et al., Nature Astronomy, 2023).
• SN 1987A (2024). Emission lines from argon in the heart of the 1987 supernova pointed to a neutron star hidden there (Fransson et al., Science, 2024).
• Europa (2023). Carbon dioxide on Europa’s surface, concentrated in a young region, likely from its ocean.
• Interstellar comet 3I/ATLAS (2025 to 2026). JWST found a carbon-dioxide-rich coma in 2025, and in 2026 high deuterium levels that point to an origin around a very old star (3I/ATLAS).

7. Results from 2026

JWST is in its fifth observing cycle, which began on July 1, 2026, after a record 2,930 proposals. Recent results include:

• July 2026: how the giant planet WD 1856 b survived the death of its star (WD 1856 b), and, with Hubble, the first stellar-mass black hole in Omega Centauri (Omega Centauri).
• August 2026: water and fresh dust around a dying star just 0.55 light-years from the Milky Way’s central black hole (IRS 3).
• October 2026: extreme debris disks from planet-shattering collisions (extreme debris disks) and the tiny host galaxy of the most distant fast radio burst yet (FRB 20240304B).

This page is updated as new results appear. Follow the mission on its hub page, James Webb Space Telescope, and see our video library for explainers on how Webb works.

Sources

1. Rigby, J. et al. (2023). The Science Performance of JWST as Characterized in Commissioning. PASP. https://doi.org/10.1088/1538-3873/acb293 [primary]
2. Carniani, S. et al. (2024). Spectroscopic confirmation of two luminous galaxies at a redshift of 14. Nature 633, 318. https://doi.org/10.1038/s41586-024-07860-9 [primary]
3. Naidu, R. P. et al. (2025). MoM-z14. Open Journal of Astrophysics. https://arxiv.org/abs/2505.11263 [primary]
4. Maiolino, R. et al. (2024). A small and vigorous black hole in the early Universe. Nature. https://doi.org/10.1038/s41586-024-07052-5 [primary]
5. Rusakov, V. et al. (2026). Little red dots as young supermassive black holes in dense ionized cocoons. Nature 649, 574. https://doi.org/10.1038/s41586-025-09900-4 [primary]
6. Lagrange, A.-M. et al. (2025). Evidence for a sub-Jovian planet in the young TWA 7 disk. Nature 642, 905. https://doi.org/10.1038/s41586-025-09150-4 [primary]
7. Riess, A. G. et al. (2024). ApJL 962, L17. https://arxiv.org/abs/2401.04773 [primary]
8. Freedman, W. L. et al. (2025). Status Report on the Chicago-Carnegie Hubble Program. https://arxiv.org/abs/2408.06153 [primary]