The James Webb Space Telescope is an incredible tool that can capture light from galaxies that formed over 13 billion years ago. Launched in December 2021, this telescope orbits more than a million miles from Earth, taking stunning images of deep space. But how does it work and how can it see so far? The secret lies in its powerful cameras that can detect infrared light, which is invisible to our eyes.
When the Webb telescope takes a picture of a distant galaxy, it is like looking back in time billions of years to see what that galaxy looked like. The light from these galaxies has traveled across space for billions of years before reaching the telescope’s mirror, allowing us to glimpse the early universe.
Unlike regular cameras, the Webb telescope is designed to capture infrared light, which is invisible to our eyes but can be detected as heat. This allows the telescope to study some of the earliest and most distant objects in space. The telescope’s giant golden mirror, coated in real gold, collects this ancient light and reflects it into its instruments.
The two main cameras on the telescope, NIRCam and MIRI, are essential for capturing images of galaxies and stars. NIRCam images near-infrared light, while MIRI detects longer infrared wavelengths. Both cameras are incredibly sensitive and can detect faint heat from billions of light-years away.
To stay cold and detect these faint signals, the Webb telescope has a giant sun shield and special refrigeration for MIRI. Once the light reaches the telescope’s cameras, it is converted into digital data and sent back to Earth to be processed into full-color images.
The colors we see in these images are assigned to different wavelengths to help us understand the composition and structure of galaxies and stars. By collecting invisible infrared light and converting it into images, the Webb telescope allows us to see galaxies that formed just after the universe began.
