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On a cloudy winter’s day, in the Amazon jungle, a shuttle blasted off into space — and changed our view of the universe forever.
About a month later, it reached its orbiting parking place in space, a gravitationally-stable Lagrange point 930,000 miles (1.5 million kilometers) away, in perfect equilibrium between Earth and the sun’s gravity. The telescope would beam back its first, spectacular pictures in July 2022. And the firehose of data it has sent back since has transformed our understanding of the cosmos.
JWST has been so pivotal in part because it can peer back to the “cosmic dawn,” a period a few hundred million years after the Big Bang, when the first stars were winking on.
“The James Webb Space Telescope has proven itself capable of seeing 98% of the way back to the Big Bang,” Peter Jakobsen, an affiliate professor of astrophysics at the University of Copenhagen in Denmark, previously told Live Science in an email.
Yet Webb, which was first conceived at Lockheed Martin in the late 1990s, almost didn’t launch at all. The now-iconic, $10 billion project was catastrophically over budget, plagued by years’ worth of delays and snarled by “stupid mistakes.”
That was in part because, when it launched, it was by far the most complex telescope ever built.
It took more than 20,000 engineers and hundreds of scientists to design, build and launch the eye in the sky. That 21.3 feet (6.5 meter) mirror had to be folded into a honeycomb shape to be lofted on a rocket, then unfolded once in space. Yet despite being foldable, it also had to be so smooth that if it were as big as a continent, “it would feature no hill or valley greater than ankle height,” according to Quanta Magazine.
To see the earliest epochs of cosmic history, Webb needed infrared vision. That’s because ancient light has been stretched, or red-shifted, into infrared wavelengths as it travels across space-time. On Earth, humans and every other living thing give off heat in the form of infrared radiation, and that would drown out the faint infrared signals from the most distant, ancient starlight. So JWST needed to be lofted into the cold dark of outer space to use its infrared instruments.
Once JWST started imaging the cosmos, it promptly began breaking our existing models of the universe. It rapidly confirmed the Hubble tension — the discrepancy between the universe’s expansion rates depending on where and what astronomers measure. It has found hints of potentially life-sustaining atmospheres shrouding distant exoplanets. And it has spotted shockingly bright galaxies and seemingly “impossible” black holes at the dawn of time. All these clues are pointing to new understandings of the universe.
Some of the questions JWST is raising, such as whether other planets harbor life, it will probably not be able to answer in its planned 10-year lifespan. But future telescopes — such as the currently operational Vera C. Rubin Observatory, meant to create a real-time “movie of the universe”; the recently completed Nancy Grace Roman Telescope, set to launch in 2027 and resolve questions about dark matter and energy; the Extremely Large Telescope, set to turn on in 2029; or the recently announced Habitable Worlds Observatory, which may come online in the 2030s — could start to answer the questions that Webb is raising.
