''Webb's First Deep Field'' is the first

operational image An operational image, also known as operative image, is an image that serves a functional, rather than aesthetic, purpose. Operational images are not intended to be viewed by people as representations of the real world; they are created to be used ...

taken by the

James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ...

(JWST). The deep-field photograph, which covers a tiny area of sky visible from the Southern Hemisphere, is centered on SMACS 0723, a

galaxy cluster A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. Clusters consist of galax ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Volans Volans is a constellation in the southern sky. It represents a flying fish; its name is a shortened form of its original name, Piscis Volans. Volans was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirks ...

. Thousands of

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar Sys ...

are visible in the image, some as old as 13 billion years. It is the highest-resolution image of the early universe ever taken. Captured by the telescope's Near-Infrared Camera (NIRCam), the image was revealed to the public by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

on 11 July 2022.

Background

The

is a

space telescope A space telescope (also known as space observatory) is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO ...

operated by

and designed primarily to conduct

infrared astronomy Infrared astronomy is a sub-discipline of astronomy which specializes in the astronomical observation, observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 microm ...

. Launched in December 2021, the spacecraft has been in a

halo orbit A halo orbit is a periodic, non-planar orbit associated with one of the L1, L2 or L3 Lagrange points in the three-body problem of orbital mechanics. Although a Lagrange point is just a point in empty space, its peculiar characteristic is th ...

around the second Sun–Earth

Lagrange point In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the gravitational influence of two massive orbiting bodies. Mathematically, this involves t ...

(L₂), about from Earth, since January 2022. At L₂, the

gravitational pull In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force be ...

of the Sun combines with the gravitational pull of the Earth to produce an orbital period that matches Earth's, and the Earth and Sun remain co-aligned (as seen from that point) as the Earth and the spacecraft orbit the Sun together. ''Webb's First Deep Field'' was taken by the telescope's Near-Infrared Camera (NIRCam) and is a composite produced from images at different

wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...

s, totalling 12.5 hours of exposure time. SMACS 0723 is a galaxy cluster visible from Earth's Southern Hemisphere, and has often been examined by Hubble and other telescopes in search of the deep past.

Scientific results

The image shows the galaxy cluster SMACS 0723 as it appeared 4.6 billion years ago, covering an area of sky with an

angular size The angular diameter, angular size, apparent diameter, or apparent size is an angular separation (in units of angle) describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the '' visua ...

of 2.4 arcminutes, approximately equal to a grain of sand held at arm's length. Many of the objects in the image have undergone notable

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

due to the

expansion of space The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time. It is an intrinsic expansion, so it does not mean that the universe expands "into" anything or that space ex ...

over the extreme distance traveled by the light radiating from them. The redshifts of nearly 200 of these objects have been measured to date, with the highest redshift measured at 8.498. The combined mass of the galaxy cluster acts as a

gravitational lens A gravitational lens is matter, such as a galaxy cluster, cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's Ge ...

, magnifying and distorting the images of much more distant galaxies behind it. Webb's NIRCam brought the distant galaxies into sharp focus, revealing tiny, faint structures that had never been seen before, including

star cluster A star cluster is a group of stars held together by self-gravitation. Two main types of star clusters can be distinguished: globular clusters, tight groups of ten thousand to millions of old stars which are gravitationally bound; and open cluster ...

s and diffuse features.

Diffraction spikes in the photo

$JWST_diffraction_spikes$ The six bright and two fainter spikes around the point sources of light in the photo are an artifact created by the physical limitations of the telescope. The six bright spikes are a result of

diffraction Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation ...

from the mirror's edges. The mirror is composed of 18 individual units, each having the shape of a

regular hexagon In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A regular hexagon is de ...

. The hexagonal rim of the units that make up the telescope's large mirror give rise to the six spikes. Telescopes with circular mirrors/lenses don't have such spikes (in lieu of spikes, diffraction from circular rims creates a pattern of concentric rings called Airy discs). The two additional spikes are a result of diffraction from the struts holding the telescope's secondary mirror in front of the main mirror. As shown in the figure on the right, diffraction from the three struts creates six spikes, but four of these are designed to co-align with the spikes created from the diffraction caused by the rim. This leaves the two faint horizontal spikes visible in the photo.

Significance

Deepest image of the Universe

On 11 July 2022, JWST delivered the deepest sharp infrared image of the universe to date. ''Webb's First Deep Field'' is the first full

false-color False colors and pseudo colors respectively refers to a group of color rendering methods used to display images in colors which were recorded in the visible or non-visible parts of the electromagnetic spectrum. A false-color image is an im ...

image from the JWST, and the highest-resolution infrared view of the universe yet captured. The image reveals thousands of galaxies in a tiny sliver of the universe, with Webb's sharp near-infrared view bringing out faint structures in extremely distant galaxies, offering the most detailed view of the early universe to date. Thousands of galaxies, which include the faintest objects ever observed in the infrared, have appeared in Webb's view for the first time. It was first revealed to the public during an event on 11 July 2022 by U.S. President

Joe Biden Joseph Robinette Biden Jr. (born November 20, 1942) is an American politician who was the 46th president of the United States from 2021 to 2025. A member of the Democratic Party (United States), Democratic Party, he served as the 47th vice p ...

Comparison with the Hubble Space Telescope

The following images are a comparison with the image taken by the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

and the image taken by Webb of the same galaxy cluster.

References

{{Sky, 07, 23, 19.5, -, 73, 27, 15.6 James Webb Space Telescope Physical cosmology Sky regions Astronomy image articles 2022 in spaceflight 2020s photographs Color photographs 2022 works