A single 120-hour exposure by the James Webb Space Telescope has captured more galaxies than any previous image — rewriting our picture of the early universe.
The James Webb Space Telescope has done it again. In April 2026, astronomers released what they are calling the deepest infrared image of the universe ever taken — a single field containing an estimated 10,000 galaxies that had never been detected before, many of them from the universe's first 400 million years of existence.
Astronomers chose the target field with extreme care — a region of sky containing virtually no foreground stars from our own galaxy. This makes it a near-perfect window into deep time. Webb's NIRCam instrument, sensitive to wavelengths from 0.6 to 5 micrometres, can detect light from objects so distant that it has been stretched by cosmic expansion from ultraviolet into the infrared.
Standard cosmological models predict that the universe built up its large structures gradually — small clouds of hydrogen collapsing into the first stars, those stars forming clusters, clusters merging into early galaxies over hundreds of millions of years. The new image challenges this picture. Several of the detected objects appear fully formed and surprisingly massive just 400 million years after the Big Bang. Theorists are now debating whether star formation in the early universe was dramatically more efficient than assumed, or whether some aspect of our cosmological model requires revision.
"We expected to find a few surprises. We did not expect to find galaxies this big this early. It is a genuine challenge to our understanding."
— Lead author, Space Telescope Science Institute, 2026The findings have been submitted to The Astrophysical Journal and are already prompting a wave of follow-up proposals to use Webb's spectroscopy capabilities to confirm redshifts and chemical compositions for the most distant candidates. The next image in this programme, with a 200-hour exposure, is already planned for late 2026.