NASA’s James Webb Space Telescope is wobbly—scientists have a fix that could reveal new alien worlds

November 4, 2026

3 min read

Add Us On GoogleAdd SciAm

By modeling the James Webb Space Telescope’s tiny movements, a new technique can reveal up to 15 times fainter alien worlds

By Jacek Krywko edited by Sarah Lewin Frasier

Directly spotting a planet around another star is like trying to see the constellations at noon. Even the biggest planets can be more than 10,000 times fainter than the stars they circle, and their light gets lost in the glare. In a new Nature study, astronomers built clever software for the James Webb Space Telescope that makes this task less challenging, giving the observatory a better chance of spotting planets closer to their stars. The software has already revealed a new view of a known giant planet hidden in JWST data.

Researchers remove the majority of a star’s glare from JWST images using a mask inside the telescope called a coronagraph that blocks most of the star’s light. “It is something like an artificial eclipse,” says the study’s lead author Rodrigo Ferrer-Chavez, an astronomer at Northwestern University. A little glare still leaks through, so astronomers also image a similar “reference star” or stars and subtract the glare they measure from the new image.

But this template is a snapshot taken by the telescope at a different moment—and a telescope is never in the same state twice. Stars sit slightly off-center, temperatures shift, JWST’s 6.5-meter mirror flexes. These tiny mismatches leave smudges of starlight that can hide a faint planet in the image, meaning that the telescope’s ability to see smaller planets is limited by its overall stability.

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

Today JWST can detect worlds roughly the size of Saturn orbiting their stars farther out than Pluto orbits our sun. To directly image Earth-sized worlds, we’d need a telescope between 100 and 1,000 times more stable than JWST, which we have not yet achieved even in lab conditions, Ferrer-Chavez says.

The researchers’ new software, called Physics-Based Learning for Imaging Planets (FLIP), incorporates a detailed physical understanding of how the telescope and its mirrors work and simulates how it would take in starlight, instabilities and all. Rather than borrowing glare from other stellar measurements, FLIP simulates it based on how the light of the target star travels through this virtual telescope. After tuning their simulation to match real observations, researchers used FLIP to remove the glare and see planets smaller than the telescope’s hardware limits normally allow.

Ferrer-Chavez and his colleagues tested FLIP on JWST observations of three star systems and found the method was two to 15 times more sensitive than standard techniques. In one of those systems, the software also captured the giant planet 51 Eridani b, a world that was not previously visible at the wavelengths that JWST can detect. On top of that, the gains FLIP brings are biggest close to stars, where planets like Earth tend to orbit.

“This is a significant result,” says Dimitri Mawet, a senior research scientists at NASA’s Jet Propulsion Laboratory, who was not involved in the study. He adds that a model-based method of removing stars’ glare from telescope images has been discussed for more than a decade, but until now it could not beat methods based on physically measuring reference stars. “Ferrer-Chavez and colleagues show that it can,” Mawet says.

Ultimately, Ferrer-Chavez says, the goal of FLIP is to make it easier to build NASA’s Habitable Worlds Observatory (HWO), JWST’s successor, which is planned to launch in the 2040s. If image-processing software can better clean up stars’ glare, the hardware can be allowed to wobble a bit more. “Physics-based postprocessing like this could plausibly ease part of HWO’s stability error budget, and that alone would matter,” Mawet says, although HWO’s optics will still need to hold steady to within a trillionth of a meter to photograph Earth-like planets that are some 10 billion times fainter than their stars.

As Ferrer-Chavez puts it, “If our approach works, building this new observatory may be really hard but not really, really, really hard.”

Subscribe to Support Independent Journalism

Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.

When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.

Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber