Greenbelt, Maryland, USA · 11 July 2022 — NASA, in partnership with the European Space Agency (ESA) and the Canadian Space Agency (CSA), released the first full-colour infrared image from the James Webb Space Telescope (JWST). Known as "Webb's First Deep Field," the image captures the galaxy cluster SMACS 0723 as it appeared 4.6 billion years ago, revealing thousands of galaxies — including some of the faintest objects ever observed in the infrared.
US President Joe Biden unveiled the image during a White House event on 11 July 2022, with the full suite of early release images following on 12 July. The deep field represents the deepest and sharpest infrared image of the distant universe ever captured at that time.
The Target: SMACS 0723
The image centres on the galaxy cluster SMACS 0723, located in the southern constellation of Volans. The cluster's immense mass — equivalent to hundreds of trillions of solar masses — acts as a gravitational lens, bending and magnifying the light from far more distant galaxies lying behind it. This effect, predicted by Einstein's general theory of relativity, effectively turns the cluster into a natural cosmic magnifying glass.
The gravitational lensing revealed faint, tiny structures in distant galaxies — including star clusters and diffuse features — that were previously invisible to any telescope. Some of the most distant galaxies visible in the image are seen as they existed over 13 billion years ago, meaning their light has been travelling for more than 13 billion years to reach the telescope's mirrors.
The patch of sky captured in the image is extraordinarily small — roughly the size of a grain of sand held at arm's length by a person on the ground. Yet within that tiny sliver, thousands of galaxies are visible.
Engineering Behind the Image
The James Webb Space Telescope, launched on 25 December 2021 aboard an Ariane 5 rocket from French Guiana, is the largest and most powerful space telescope ever built. Its 6.5-metre primary mirror, composed of 18 hexagonal gold-coated beryllium segments, collects infrared light that has been stretched by the expansion of the universe from visible and ultraviolet wavelengths into the infrared regime.
Webb operates at infrared wavelengths because the most distant objects in the universe are receding so rapidly that their light has been redshifted far beyond the visible spectrum. To detect this faint infrared radiation, the telescope must be kept extremely cold — approximately 50 Kelvin (-223°C) — shielded from the heat of the Sun, Earth, and Moon by a five-layer sunshield the size of a tennis court.
The telescope orbits the Sun at the second Lagrange point (L2), approximately 1.5 million kilometres from Earth, a gravitationally stable location that allows it to maintain its position relative to both the Sun and Earth while keeping its instruments perpetually shaded.
The Diffraction Spikes
The bright foreground objects in the image, displaying prominent six-pointed star-like patterns, are individual stars within our own Milky Way galaxy. These "diffraction spikes" are an optical artefact produced by Webb's hexagonal mirror segment design and the support structure for the secondary mirror. They are not features of the stars themselves but rather a signature of the telescope's architecture — a visual fingerprint that distinguishes Webb images from those taken by Hubble, whose diffraction spikes typically have four points.
A New Era of Infrared Astronomy
Webb's First Deep Field was not merely a single image but a demonstration of the telescope's transformative capability. The image was created using Webb's Near-Infrared Camera (NIRCam), which images the sky in multiple infrared filters. Each filter captures a different wavelength band, and the composite combines these into a colour image where the shortest wavelengths appear blue and the longest appear red.
Scientific Follow-Up
The deep field image immediately became a target for spectroscopic follow-up. Webb's Near-Infrared Spectrograph (NIRSpec) can obtain spectra of multiple galaxies simultaneously using its microshutter array, allowing astronomers to measure redshifts, chemical compositions, and star formation histories for dozens of galaxies in a single observation.
One of the first spectroscopic results from the SMACS 0723 field confirmed the redshift of a galaxy at z = 8.498, placing it within the first 600 million years after the Big Bang. Subsequent analysis of even more distant candidates in the field has pushed these boundaries further, with some galaxies potentially seen at redshifts exceeding 13 — corresponding to less than 300 million years after the Big Bang.
The Full Early Release Programme
The SMACS 0723 deep field was one of five targets in Webb's Early Release Observations (ERO) programme, unveiled on 12 July 2022. The others included:
| Target | Type | Significance |
|---|---|---|
| Carina Nebula | Stellar nursery | Revealed previously hidden star formation in cosmic dust |
| Southern Ring Nebula | Planetary nebula | Showed a dying star's outflows in unprecedented detail |
| Stephan's Quintet | Galaxy group | Visualised gravitational interactions and tidal disruption |
| WASP-96b | Exoplanet | First Webb exoplanet transmission spectrum, detecting water vapour |
Together, these early observations demonstrated Webb's ability to address fundamental questions across astrophysics — from the formation of stars and planets to the assembly of galaxies in the early universe.
An International Partnership
The James Webb Space Telescope is an international programme led by NASA with its partners, ESA and CSA. ESA provided the Ariane 5 launch, the NIRSpec instrument, and 50% of the MIRI instrument. CSA contributed the Fine Guidance Sensor/Near-Infrared Imager and Slitless Spectrograph (FGS/NIRISS). More than 1,200 scientists, engineers, and technicians across 14 countries contributed to the telescope's design, construction, and commissioning.
Sources
- NASA, "NASA's Webb Delivers Deepest Infrared Image of Universe Yet," 11 July 2022, nasa.gov
- ESA/Webb, "Webb's First Deep Field," esawebb.org, 12 July 2022
- NASA, "President Biden Reveals First Image from NASA's Webb Telescope," 11 July 2022, nasa.gov
- Space Telescope Science Institute, JWST documentation, stsci.edu
- Planetary Society, "Webb's First Deep Field: SMACS 0723," planetary.org, July 2022
FIRAT Editorial Board
Institutional Research Desk · Foresight Institute of Research and Translation
The collective editorial and research translation board of FIRAT, synthesising peer-reviewed evidence, policy briefs, and division milestones across our seven foundational research pillars.
