The James Webb Space Telescope (JWST) has ushered in a new era of astronomy with its unprecedented infrared vision. As JWST celebrates its second birthday, let’s recap some of its most groundbreaking observations that have transformed our understanding of the early universe.
Peering Back 13 Billion Years
In July 2022, President Biden unveiled JWST’s first full-color image – the deepest view of the universe ever captured. This image, known as Webb’s First Deep Field, peers back over 13 billion years to just a few hundred million years after the Big Bang.
JWST reveals hundreds of previously unseen galaxies in this tiny patch of sky, including some of the most distant galaxies ever observed. As TIME reports, this was the first time humanity has directly observed light from such young galaxies formed shortly after the Big Bang.
The galaxies appear extraordinarily small, uneven, and chaotic compared to galaxies today – providing clues to the primitive conditions of the early universe. This Deep Field will allow astronomers to study the origins of galaxies in unprecedented detail.
|Over 13 billion lightyears
|Within a few hundred million years of the Big Bang
Record-Breaking Views Spanning Cosmic History
In August 2022, JWST revealed images of the galaxy cluster SMACS 0723 showing the farthest humanity has ever seen in both time and distance:
JWST observed a galaxy nicknamed GLASS-z13 – the earliest galaxy glimpsed so far at over 13.4 billion light-years away, when the universe was only 300 million years old. This surpasses Hubble’s previous record galaxy by about 100 million years.
Due to the expanding universe, the light from GLASS-z13 has been significantly redshifted. JWST’s specialized infrared instruments were able to detect this faint, highly redshifted light.
The gravity of the galaxy cluster also creates a “natural telescope” amplifying the light of galaxies behind it. This gravitational lensing effect enabled JWST to see GLASS-z13.
Studying early galaxies like GLASS-z13 provides clues to when the first stars and galaxies formed after the universe was created in the Big Bang.
JWST is uniquely equipped to gather more census data on the earliest galaxies and compare them to computer models explaining the evolution of the universe. Its observations in gravitational lenses also give astronomers a boosted look at extremely distant galaxies.
Uncovering Hidden Galaxies
In December 2022, a JWST observation revealed a galaxy from the surprisingly early period of 300-400 million years after the Big Bang. Nicknamed “Nyx”, this previously invisible galaxy was spotted behind the massive foreground galaxy cluster Abell 2744:
Nyx existed only 500 million years after the Big Bang but has a mass already containing 100 billion stars. This challenges theories about the origins and evolution speed of galaxies.
The discovery of Nyx was only possible thanks to JWST’s high resolution at infrared wavelengths and the gravitational lensing effect of the galaxy cluster.
Finding more galaxies like Nyx will allow correlations between the properties, numbers, and distributions of early galaxies and theoretical models. This provides essential clues to conditions in the infant universe.
Astronomers were surprised to find a galaxy as developed as Nyx existing so soon after the first stars emerged. JWST’s sensitivity, resolution, and infrared capabilities are perfect for uncovering more hidden primitive galaxies and piecing together the early universe.
Unveiling Spectacular Merging Galaxies
In July 2022, JWST unveiled its first stellar image capturing unprecedented details of Stephan’s Quintet, a visual grouping of five galaxies. Four of them are locked in a repeated cosmic dance, repeatedly passing by each other and creating shockwaves of gas and star formation.
This image immediately demonstrated JWST’s power to unveil previously obscured galactic features. For example, JWST revealed over a thousand brilliant clumps of newly formed stars too distant to be seen by Hubble.
In December 2022, JWST observed an extremely turbulent and chaotic six-way galactic pileup forming a single massive galaxy over a billion lightyears away. Nicknamed the “Molten Ring Galaxy”, this is the earliest mid-sized merging galaxy system ever observed:
- The Molten Ring galaxy weighs as much as 6 Milky Way galaxies combined but is compacted into a region only tens of thousands of lightyears across.
- JWST reveals arcs and loops of stars violently thrown around as the six galaxies coalesce into one. Tidal tails over 130,000 lightyears long also emerge.
- Extreme bursts of star formation glow brilliantly across the system due to vast clouds of gas crashing and compressing together.
Studying merging galaxies gives clues to galaxy evolution and growth. JWST’s infrared vision can peer through dust to expose fine details of stellar features and starbirth. As the most powerful infrared telescope, JWST will observe galaxy interactions across cosmic time unlike any before.
In only 18 months, JWST has already fundamentally impacted astronomy by unveiling unprecedented views of the infant universe shortly after the Big Bang. JWST has spotted early galaxies barely 300 million years old, broken distance records by billions of lightyears, uncovered hidden primitive galaxies, and showcased its power on spectacular merging galactic systems.
As JWST shifts to its normal science operations phase past commissioning milestones, astronomers worldwide are thrilled by the promise of its remaining years. JWST is providing transformational infrared observations across the cosmos spanning from our solar system to the most distant observable galaxies. There are sure to be many more unexpected, exciting discoveries that challenge our theories and reveal intricate new details about our dynamic, evolving universe.
TIME. “James Webb Space Telescope’s Best Photos From 2023.” TIME, 10 January 2023. https://time.com/6513062/james-webb-telescope-best-photos-2023/. Accessed 25 December 2023.
Astronomy. “The 10 Greatest JWST Discoveries So Far.” Astronomy.com, 7 December 2022. https://www.astronomy.com/science/the-10-greatest-jwst-discoveries-so-far. Accessed 25 December 2023.
NASA. “A Look Through Time with NASA’s Lead Photographer for the James Webb Space Telescope.” Science Mission Directorate, 23 December 2023. https://science.nasa.gov/missions/webb/a-look-through-time-with-nasas-lead-photographer-for-the-james-webb-space-telescope. Accessed 25 December 2023.
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