Key points
- Since its launch in 2022, Webb has probed deep into the infrared spectrum
- Infrared spectrum is a capability essential for detecting extremely redshifted light
- As the universe expands, light from early galaxies stretches to longer, redder wavelengths
- The phenomenon is known as cosmological redshift
ISLAMABAD: In a cosmic feat that feels nothing short of magical, NASA’s James Webb Space Telescope (JWST) is allowing us to peer nearly to the dawn of time, capturing light from galaxies that formed when the universe was a baby.
Since its launch in 2022, Webb has probed deep into the infrared spectrum, a capability essential for detecting extremely redshifted light. As the universe expands, light from early galaxies stretches to longer, redder wavelengths—a phenomenon known as cosmological redshift.
According to NASA, Webb’s powerful infrared instruments, combined with its enormous 6.5‑meter mirror and high resolution, act like a time-travelling telescope, bringing ancient cosmic light into view.
One of Webb’s standout discoveries is the galaxy JADES‑GS‑z13‑1.
According to Reuters, this object, observed only 330 million years after the Big Bang, displays unexpectedly strong Lyman‑α hydrogen emissions—signals previously thought impossible at such an early epoch because of the dense, foggy hydrogen that filled the universe.
A tell-tale sign
The presence of this emission suggests Webb observed a “bubble” of ionised hydrogen, a telltale sign that some galaxies were already piercing this cosmic fog far earlier than believed.
Beyond Lyman‑α light, Webb has captured thousands of distant galaxies in deep‑field images—some dating back just a few hundred million years after the Big Bang. Many exhibit intense star formation and clumpy, irregular structures typical of the early universe, according Live Science.
These findings are helping unravel the mystery of the “Epoch of Reionisation,” the moment when the universe transitioned from opaque fog to transparent cosmos.
Webb’s unique blend of sensitivity, resolution, and infrared vision has truly transformed our understanding of cosmic history. Each faint galaxy it unveils is not just distant—they are millennia-old messengers, revealing how the earliest stars, black holes, and galaxies shaped everything we see today.
