James Webb Space Telescope

Peering into the Universe’s Depths

Article by Rumeshika Kanagaraj, 2nd Year Undergraduate


The James Webb Space Telescope stands as the beacon of humanity’s relentless quest to unravel the mysteries of the cosmos. Positioned as the successor to the venerable Hubble Telescope, it represents a leap forward in our ability to observe and understand the universe. Its name pays homage to James E. Webb, a pivotal figure in NASA’s history, underscoring its significance in pushing the boundaries of our knowledge. Collaboratively crafted by National Aeronautics Space Administration (NASA), the European Space Agency (ESA), and the Canadian Space Agency (CSA), the telescope underwent meticulous preparation over several years. Its development journey, marked by persistent challenges and triumphs, culminated in its successful launch.

The mission’s duration spans an ambitious timeline, with an expected operational lifespan extending over a decade. Despite encountering setbacks during its development, the telescope’s resilience shone through, ultimately ensuring its success upon launch. Since its deployment, the James Webb Space Telescope now orbits at a near the sun-earth L2 Lagrange point million kilometers beyond the earth’s atmosphere, free from the distortions that hinder ground-based observations. Equipped with advanced infrared capabilities, it delves into the universe’s depths, peering through cosmic dust clouds and unveiling celestial phenomena invisible to optical telescopes.

The Webb observatory has four main elements the telescope, the instrument module, the sunshield and the spacecraft bus. The James Webb Space Telescope boasts a primary mirror comprised of 18 hexagonal segments, totaling a diameter of 6.5 meters. This intricate mirror system gathers light, crucial for its sensitivity and resolution. Alongside the primary mirror, secondary, tertiary, and fine-steering mirrors play pivotal roles in directing light towards the telescope’s instruments. The secondary mirror, uniquely convex, guides light towards the tertiary mirror, the central fixed element of the system. Together, they ensure precise light alignment for optimal observation.

Shielded by a tennis court-sized sunshield, consisting of five layers of reflective membranes, the telescope remains cool in space. This is vital as Webb operates in the infrared spectrum, detecting wavelengths beyond human vision. Infrared sensitivity requires low temperatures to prevent internal heat interference with faint astronomical signals. The combination of these intricate mirror assemblies and the advanced sunshield empowers Webb to achieve unparalleled infrared vision. This capability positions it as NASA’s most sophisticated space observatory, poised to unveil the universe’s hidden secrets with unprecedented clarity and depth.

The main purpose of the James Webb Space Telescope is to unravel the universe’s mysteries, from probing the atmospheres of distant exoplanets to studying the formation of galaxies billions of light-years away. Its first images captivated the world, offering unprecedented glimpses into the cosmos’s beauty and complexity.

When the telescope released its inaugural images, it marked a watershed moment in astronomical history. Each snapshot, accompanied by awe-inspiring titles, unveiled celestial wonders previously unseen by human eyes, igniting imaginations and inspiring future generations of astronomers.


Figure 1: The image depicts JWST’s 18 mirrors fully coated in gold. A microscopically thin layer of gold enhances the mirrors’ reflectivity to infrared light.

The Webb Space Telescope was launched on December 25, 2021, aboard an Ariane 5 rocket from the spaceport in Kourou, French Guiana. In January 2022, it reached its position in space, and on July 11, 2022, the first image was released by USA President Joe Biden, known as Webb’s first deep field, featuring the galaxy cluster SMACS 0723. Subsequently, on December 12, 2022, NASA released other colorful observations from Webb, including images of Stephan’s Quintet, the Carina Nebula, the detailed atmospheric composition spectrum of the hot gas giant exoplanet WASP-96 b, and the southern ring nebula.

SMACS 0723 unveils a galaxy cluster brimming with thousands of galaxies, including some of the faintest objects ever detected in the infrared spectrum. Acting as a gravitational lens, the cluster magnifies distant galaxies behind it, offering a detailed glimpse into the early universe, showcasing galaxies as they appeared 4.6 billion years ago. Stephan’s Quintet 3, a compact galaxy group, was captured in a vast mosaic by JWST, revealing fresh insights into the interactions among its galaxies. The image showcases young stars, starburst regions, and sweeping tails of gas, dust, and stars resulting from gravitational interactions. Notably, NGC 7318B, one of the galaxies, generates massive shock waves as it plows through the cluster.

JWST’s imaging of the “Cosmic Cliffs” of the Carina Nebula in striking detail exposes previously obscured regions of star formation, highlighting the edge of a massive, gaseous cavity within NGC 3324. The image vividly captures the dynamic processes shaping the nebula, including the influence of intense ultraviolet radiation from young stars. Additionally, JWST provided a detailed atmospheric composition spectrum of the hot gas giant exoplanet WASP-96 b. The transmission spectrum indicates the presence of water vapor and suggests the existence of clouds that suppress water vapor features. The spectrum also hints at possible haze in the planet’s atmosphere. Furthermore, JWST’s imaging of the southern ring nebula, also known as NGC 3132, reveals intricate structures molded by two central stars. The image displays the nebula’s complex rings and “spokes” of gas and dust, offering insights into the late stages of stellar evolution.


Figure 2: image of galaxy cluster 0723 compared with Webb’s near infrared and visible light. Left side image represent visible light and right-side image represent infrared light.

These images from JWST not only provide a glimpse into the distant cosmos but also significantly contribute to our understanding of the universe’s structure and evolution. They showcase the telescope’s remarkable ability to capture the universe in unprecedented detail, enabling astronomers to study these objects with newfound depth and clarity.

Amazing observation of James Webb Space Telescope by over a year

Star born in pillar of creation

JWST’s superiority in observing the Pillars of Creation lies in its advanced capabilities, particularly in the infrared spectrum. Unlike Hubble, which primarily operates in the visible and ultraviolet wavelengths, JWST’s infrared sensitivity allows it to penetrate the thick dust clouds surrounding the pillars, revealing hidden details and processes crucial to star formation. Moreover, JWST’s high-resolution imaging capabilities would enable astronomers to study the dynamics of the pillars in greater detail, such as the effects of stellar winds and radiation from nearby massive stars on their morphology and evolution. Overall, JWST’s observations of the Pillars of Creation would contribute significantly to our understanding of star formation processes and the lifecycle of interstellar clouds in the Eagle Nebula.

Exo planet HIP 65426 b

In September 2022, JWST captured its first direct image of an exoplanet, HIP 65426 b, which was discovered in 2017. Scientists utilized two of Webb’s cameras, multiple filters, and coronagraphs to block out the central star’s light for observation. The planet’s unique characteristics, including its position at a distance 100 times farther from its host star than Earth is from the sun and its colossal size (roughly 12 times larger than Jupiter), make it particularly conducive to observation.


Figure 3: The James Webb Space Telescope’s image of NGC 628, also known as the “Phantom Galaxy,” reveals luminous dust in this citizen science depiction.

Although the Phantom Galaxy may be challenging to locate in the night sky, its brilliance becomes unmistakable when viewed through Webb’s infrared lens. While Hubble’s telescope previously captured an image of this galaxy, showcasing its pristine spiral structure and the arrangement of its stars with arms extending outward from a luminous core, a new image from Webb unveils intricate fiber-like structures composed of heat-emitting dust and gas. These structures emanate from a bright center, depicted in vivid electric blue. This new image promises to illuminate star-forming regions scattered throughout the galaxy’s spiral arms, providing valuable insights into its dynamic processes.

Titan’s Clouds

Titan, Saturn’s moon, presents a fascinating and unusual landscape. It features “rocks” composed of water ice and boasts rivers, lakes, and seas filled with liquid methane and ethane. also, Titan stands out as the sole moon in our solar system to possess a thick, hazy atmosphere adorned with methane clouds. In November, Webb provided scientists with a glimpse of these clouds, capturing atmospheric data from this intriguing celestial body. Surprisingly, the telescope detected not just one, but two clouds, including one situated above Titan’s largest sea, Kraken Mare. This discovery prompted the team to collaborate with the Keck Observatory in Hawaii, which conducted observations of Titan just two days later. The Keck observations revealed a cloud above Kraken Mare in a similar location, albeit with a different shape, suggesting either a change in the cloud’s formation or the σarrival of a new cloud in the same area. The team anticipates that insights from data like this will aid in mapping Titan’s haze and uncovering new gases within its atmosphere.


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