The James Webb Space Telescope (JWST) stands as a marvel in the exploration of the cosmos, capturing the universe with a level of precision and sensitivity that is unparalleled. Its images, ranging from the stunning blues and golds of the Southern Ring Nebula to the captivating pinks, oranges, and purples of Cassiopeia A, not only serve scientific purposes but also dazzle the eye with their beauty.
These breathtaking images might lead one to wonder: do these celestial bodies truly exhibit such vibrant colors? How would they appear to the naked eye, unaided by the technology of a telescope?
Alyssa Pagan, a science visuals developer at the Space Telescope Science Institute (STScI) and a key player in bringing color to JWST’s images, admits that the true appearance of these cosmic wonders remains a mystery. However, one thing is certain: our unaided eyes would not perceive the universe in the same way.
The JWST operates primarily in the infrared spectrum, detecting wavelengths of light longer than those visible to the human eye. If we were to observe these celestial objects directly, our experience might more closely resemble that of viewing them through telescopes designed for visible light, such as the Hubble Space Telescope. However, this comparison has its limitations, given Hubble’s superior size and sensitivity, as well as the different aspects of an object that visual-light and infrared telescopes can reveal.
The process of selecting colors for these magnificent images involves viewing JWST’s targets through various filters, each attuned to specific wavelengths of infrared light. The telescope’s main camera, the Near Infrared Camera, utilizes six filters to capture slightly different images. By combining these images, Pagan and Joe DePasquale, another science visual developer at STScI for JWST, craft the full-color images we marvel at.
Initially, the images arrive in black and white. The vibrant colors are added later, translating the data from the filters into the spectrum of visible light. This translation assigns red to the longest wavelengths and blue or purple to the shorter ones, applying our understanding of light’s color spectrum to the infrared data.
Before finalization, the images may undergo further adjustments to enhance clarity or emphasize specific features. Pagan and DePasquale also collaborate with researchers to ensure the images’ scientific accuracy, especially when accompanying specific findings. While the colors in JWST’s images might not reflect what we would see with our own eyes, they are not intended to deceive. Instead, they aim to clearly communicate what the JWST perceives in the universe, beyond the limits of human vision.
“We’re just trying to enhance things to make it more scientifically digestible and also engaging,” Pagan explains.
By comparing images of the iconic Pillars of Creation taken by JWST and Hubble, one can appreciate the differences between visual-light and infrared observations. The JWST image reveals the formation in golden and orange tones, highlighting areas of star formation obscured in the Hubble image by thick clouds of gas and dust.
In essence, while the colors in JWST’s images may not be “real” in the traditional sense, they play a crucial role in conveying the unseen beauty and complexity of the universe, bridging the gap between scientific discovery and public fascination.