Unlocking the Invisible Universe: How William Herschel’s Innovations Transformed Our View of Space | Aeon Essays

The human eye is fascinating but limited. We see only a tiny slice of the electromagnetic spectrum, like hearing just a fraction of sound. Most radiation around us is invisible to us. We’re tuned into the colors of sunlight, but that’s it. From the violet to the red, we catch just one octave out of many.

Yet, our minds can grasp so much more. Technology helps us peer into the invisible. Innovations like the James Webb Space Telescope (JWST) allow us to experience the infrared spectrum, revealing a hidden universe. JWST observes light wavelengths that are 40 times longer than what our eyes can detect. Its stunning images—from colliding galaxies to newly forming stars—represent a scientific breakthrough, transforming data into visuals we can understand.

This telescope, a marvel of modern engineering, stands as proof of two centuries of progress. It’s the largest and most complex observatory launched into space, constructed from a 1988 vision by the US National Research Council that called for a space telescope to enhance our understanding of the universe. With a budget of $10 billion, JWST’s 6.5-meter mirror gathers a million times more light than our eyes can see. Behind its sunshade, it operates at an incredibly low temperature, ensuring clarity in its observations.

The roots of this technology trace back to William Herschel, an 18th-century astronomer. Herschel was known for discovering Uranus and advancing the art of telescope making. But one of his greatest contributions was discovering infrared light. Frustrated that he could only observe celestial bodies at night, he experimented with light using simple instruments and discovered that some rays were invisible to the eye but carried heat. He called this phenomenon “radiant heat,” revealing a part of reality that remained unseen.

Herschel’s work led to fundamental insights. He hypothesized that our vision only allows us to see what we need for survival. This understanding opened doors to further explorations of light—beginning a long journey of technological advances.

Following Herschel’s discoveries, significant progress occurred, albeit slowly. In 1856, Charles Piazzi Smyth confirmed infrared rays from the Moon. Over the years, other pioneers like Samuel Pierpont Langley and Robert Williams Wood advanced our understanding of infrared light. They created new instruments, allowing us to observe the previously hidden realms, but it wasn’t until the 1980s that a true infrared space telescope, IRAS, was launched. IRAS uncovered countless celestial objects, signaling a new era in astronomy.

Now, JWST takes us even further, viewing the early universe with its ability to capture the infrared light stretched by cosmic expansion. It has identified a galaxy named JADES-GS-z14-0, the most distant known object, allowing us to look back 13.4 billion years into the past when the universe was just beginning.

The excitement surrounding JWST is not merely about what we see but how it expands our understanding of the cosmos. Philosopher Andy Clark described how technology extends our cognitive abilities, suggesting that tools like JWST can reshape our mental landscape. We adapt to these technological advancements, integrating new information seamlessly into our understanding of reality.

As we probe deeper into the cosmos, exploring the once-invisible, we grow and change our perceptions. JWST is more than a telescope; it’s a bridge to unfathomable realms that not only enhance our senses but also redefine how we see ourselves in the universe.



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