Last September, JWST took this image of a protostellar jet at the outskirts of the Milky Way. From tip to tip, the jet spans about double the distance from the Sun to its closest neighbouring star system, α Centauri.Credit: NASA, ESA, CSA, STScI, Yu Cheng (NAOJ); Image Processing: Joseph DePasquale (STScI)
From black holes in the early Universe1 to atmospheres cloaking distant planets2, the James Webb Space Telescope (JWST) studies cosmic phenomena that no other observatory has been able to probe. The most powerful infrared telescope ever built, it released its first images four years ago this week.
‘It’s a dream’: JWST spies more black holes than astronomers predicted
Its success is a tribute to the talent and hard work of its scientists and engineers. Conceived in 1989, it is also testament to persistence, often against the odds — more than once, the telescope faced cancellation as its costs ballooned, eventually reaching US$10 billion for construction and the first five years of operation.
With four years under its belt, JWST has just one more year of prime-mission operations before NASA must approve an extension. The agency is also considering whether and how to end another flagship observatory: the Hubble Space Telescope. Hubble observes mostly in optical and ultraviolet wavelengths and has reshaped astronomers’ understanding of how stars and galaxies are born, evolve and die.
There is much science still to do with both telescopes, and both must be renewed. Hubble costs around $98 million to operate each year, and JWST around $200 million. These are small numbers given the immense scientific return. The telescopes complement one another beautifully: to not renew them would be like building a transformative AI technology and then disconnecting it from the Internet so it couldn’t be used.
A 50-year-old full-scale mock-up of the Hubble Space Telescope went on display last month at the Smithsonian National Air and Space Museum in Washington DC.Credit: Shannon Finney/Getty
As an infrared telescope, JWST observes wavelengths at the redder end of the electromagnetic spectrum. Because the expansion of the Universe shifts light toward the red, JWST has an unprecedented view of the most distant realms of the cosmos, where objects appear as they did not long after the Universe was born in the Big Bang, 13.8 billion years ago. This view is thanks in no small part to a large number of features constructed through engineering and technological firsts, from the 6.5-metre-wide, foldable primary mirror to a tennis-court-sized sunshield.
Among its discoveries, JWST has spotted small, distant black holes, the existence of which challenges ideas about how black holes form. It has found some of the farthest galaxies observed, including star systems that are bigger and brighter than astronomers would have expected in the early Universe. Closer to home, JWST discovered a lava world with an improbably wet atmosphere; peered through dusty disks at planets being born; and measured the chemical composition of an interstellar visitor, the comet 3I/ATLAS, which swooped past the Sun late last year3.
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The success of both telescopes is evidence of international and multidisciplinary research collaboration writ large. Hubble is a collaboration between NASA and the European Space Agency (ESA). Similarly, NASA led JWST, with ESA contributing a key instrument and the launch vehicle, among other things. The Canadian Space Agency built another crucial instrument plus sensors that keep the telescope accurately pointed in space.
The collaborations are not only pioneering excellence in engineering and science, but also attempting to do so with a strong ethical compass. Alongside NASA, leaders at the Space Telescope Science Institute in Baltimore, Maryland, which operates both Hubble and JWST, are working to counteract the biases that can skew access to large scientific facilities.
In 2018, the committees that allocate time to use the Hubble switched to a dual-anonymous review process, in which neither the applicant nor the reviewer knows who the other is. This change led to a substantial increase in proposals from female principal investigators being accepted4, and the same system is now used for JWST.
These six distant galaxies captured by JWST are wowing astronomers
As it looks to the future, JWST will need to become part of a new ecosystem of sky-surveying telescopes. Notably, the US National Science Foundation and Department of Energy’s Vera C. Rubin Observatory began its ten-year survey from Chile last month, and NASA aims to launch the Nancy Grace Roman Space Telescope next month. Both of these telescopes will scan big areas of the cosmos and identify oddities that JWST will then be able to pinpoint. The European Space Agency’s Euclid mission, launched in 2023, is deep into exploring similar questions. China plans to launch an approximately Hubble-sized telescope for its own survey of the skies next year.
How to remain relevant as the research landscape changes is a familiar challenge to any manager of a major science project. Here, JWST holds lessons. It’s important to build something distinctive and powerful enough to truly open a discovery space. Having a big facility is good; having a transformational one is much better. Since its conception, JWST has showed its strength as new astronomical fields, such as exoplanet science, came into being — and its instruments were powerful enough, and its scientists quick-thinking enough, to adapt. Many criticized the immense ambition of JWST, which contributed to the technological problems that plagued its development. But that scientific vision is now paying off in spades.
In an era of global cutbacks and threats to basic science, both Hubble and JWST radiate achievement. That can be an example to any scientific leader, in any discipline, who wants to get a highly ambitious project off the ground. The message of both is to dream big — and then deliver.
