The James Webb Space Telescope's ability to observe distant celestial bodies is attributed to its powerful infrared capabilities and precision-tuned optics.
NASA's James Webb Space Telescope Reveals the Universe's Oldest Galaxies
The James Webb Space Telescope (JWST), launched in December 2021, is revolutionising our understanding of the cosmos by capturing breathtaking images of distant galaxies, primarily using infrared light.
Infrared Detection and Analysis
Unlike traditional cameras, JWST uses highly sensitive instruments such as NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) to detect infrared light emitted by distant celestial objects. Infrared light has longer wavelengths than visible light, enabling the telescope to see through dust clouds and detect cooler, more distant objects.
NIRCam captures near-infrared light and splits it into different wavelengths, helping scientists not only see the shapes of galaxies and stars but also understand their chemical composition by analysing the unique infrared "fingerprints" of materials. MIRI detects longer mid-infrared wavelengths, ideal for spotting dusty or cooler objects like stars forming inside gas clouds.
Data Conversion and Transmission
When infrared light reaches JWST, it strikes detectors that do not capture traditional images. Instead, these detectors convert the infrared light into digital data, which is sent back to Earth. Scientists then process this data to create detailed, full-color images that reveal faint structures and the chemical makeup of extremely distant galaxies.
Extreme Sensitivity
JWST’s instruments are far more sensitive than standard Earth-based cameras – capable of detecting minuscule heat signals from billions of light-years away. For example, NIRCam's sensitivity is likened to being able to see the heat from a bumblebee on the Moon.
Gravitational Lensing
JWST also takes advantage of natural "magnification" by galaxy clusters acting as gravitational lenses, which amplify the light from even more distant galaxies behind them, enabling imaging of galaxies that formed when the universe was less than a billion years old.
An Unprecedented Look at the Universe
In summary, JWST captures images of distant galaxies by detecting and analysing their infrared light using ultra-sensitive cameras and spectrographs. This technique allows it to see through cosmic dust and observe galaxies from the early universe in unprecedented detail, producing valuable data for scientists to create images and understand galactic formation and composition.
The Largest Space Telescope Mirror Ever Launched
The JWST's mirror is the largest ever launched into space, with a diameter of over 21 feet and made of 18 smaller mirror pieces. The mirror is coated in a thin layer of real gold for efficient infrared light reflection. To block heat from the Sun, Earth, and Moon, JWST carries a giant sun shield about the size of a tennis court.
Orbiting a Million Miles from Earth
The James Webb Space Telescope is orbiting more than a million miles from Earth, with a design that allows it to see light from galaxies that formed more than 13 billion years ago. The telescope's cold operating temperature, maintained by a special refrigerator called a cryocooler for MIRI, is crucial for its sensitivity and ability to detect faint objects.
The colours in Webb's pictures aren't what the camera "sees" directly. Scientists assign colours to different wavelengths to help us understand what's in the image. The images produced by the James Webb Space Telescope are revealing new insights about the universe's past and paving the way for future discoveries.
- Science and technology combined in the James Webb Space Telescope (JWST) to capture breath-taking images of the universe's oldest galaxies, primarily using infrared light.
- NIRCam and MIRI, sensitive instruments on JWST, enable the detection of infrared light emitted by distant celestial objects, helping scientists understand their chemical composition and chemical makeup.
- Ancient galaxies, even those formed before the universe was a billion years old, can be viewed with an unprecedented level of detail thanks to JWST's ability to utilize the natural "magnification" provided by galaxy clusters acting as gravitational lenses.
- The latest discoveries in the field of space-and-astronomy are being fueled by a combination of advanced technology, history-making instruments like the JWST, and a commitment to exploring and understanding the universe's mysteries.
