Meet the NASA scientist opening up exoplanet research

In the movie Star Wars, Luke Skywalker leaves his dreary life on the planet Tatooine and embarks on a journey across the galaxy. We watch as he goes from planet to planet, exploring desert worlds, mountain worlds, and tundra worlds.

These richly depicted worlds instantly became a part of the cultural imagination. Indeed, it’s hard to remember then that when the first Star Wars film came to theaters in 1977, the only known planets in the universe were the nine orbiting our own Sun. And yet, Star Wars and other science fiction films of the time reveal how the idea of planets outside of our own solar system – called exoplanets — captivated both scientists and the general public even then. 

Though the existence of exoplanets had not yet been confirmed, astronomers speculated that there were planets orbiting other stars. In 1984, an observatory in Chile captured an image of a disk of dust orbiting a star more than 60 light years from the Sun. This disk, called a “protoplanetary disk”, is made  of cosmic material which will continue to accumulate over time and eventually form a planet.

Exoplanet research started out as an obscure niche of astronomy in the early 1990s after a pair of astronomers confirmed the existence of planets outside our solar system. Just a handful of researchers pored over data on these few known worlds outside our own solar system. Since then, the field rapidly expanded as astronomers uncovered the existence of thousands of exoplanets. 

Now, scientists are preparing to expand our knowledge of exoplanets even further by launching the largest and most powerful telescope ever sent to space — the James Webb Space Telescope. The instrument, scheduled to launch in December 2021, is more sensitive than previous observatories, so it will allow researchers to take in more information about exoplanets. The telescope will be able to detect cosmic objects at infrared frequencies. It will detect cosmic happenings which only emit infrared wavelengths, such as early galaxy formation. This longer wavelength coverage will let researchers observe previously discovered exoplanets in greater detail and prepare the field for a new era of exoplanet understanding.

“The whole point of science is to be collaborative and to share your work with people.”

While the number of young researchers making their way into exoplanet science is on the rise, one researcher is making a name for herself in part by working to keep the field accessible to all. NASA Ames Research Center scientist Natasha Batalha is using coding to pioneer the future of exoplanet science.

Batalha has created software that enables researchers to use Webb data to study which exoplanets might harbor life. And, in a radical move, Batalha is sharing her software freely rather than limiting its access. Past scientists who’ve created software have circulated it within an exclusive inner cohort. This restricted the discoveries to an elite club and slowed down the growth in the field of astronomy. Her software will break down a barrier that has prevented progress in astronomy in the past and help scientists study the atmospheres of exoplanets, looking for clues to where life might exist outside our solar system.   

Other astronomers see Batalha as a member of the new guard of scientists impassioned to bring equity to the field. 

“At the end of the day, people will look back and see how much of the Webb science she has enabled,” says Mark Marley, a scientist at NASA Ames Research Center who has worked with Batalha on exoplanet research.

Origins of an Exoplanet Scientist

Batalha became interested in space at a young age. As a child, she watched her mother, astrophysicist Natalie Batalha, lead NASA’s Kepler mission, which sent a telescope to search for planets beyond our own solar system. The younger Batalha remembers being with her mom and other scientists at Cape Canaveral in Florida on March 9, 2009, the Kepler telescope launched, beginning its more than 9 year mission. Ultimately, the Kepler mission would discover over two thousand planets and make the mesmerizing realization that our galaxy contains more planets than stars. 

As she waited for Kepler to launch, Batalha says, there was a palpable nervous tension among the scientists which gave way to “pure ecstasy, pure joy” as the rocket successfully took off.

“It’s hard to imagine someone being in the room like that and not being just absolutely drawn to pursue a similar career,” says Batalha.

As an undergraduate student at Cornell, Batalha’s interest in the worlds beyond our own developed into a tangible launching point for her career. During her senior year at Cornell, astronomer Jonathan Lunine told Batalha that NASA was planning to launch the James Webb Space Telescope. Batalha immediately saw the potential for a long-term career goal. Feeling motivated, she told Lunine she was ready to take on more work.

Lunine himself was eager to understand the Webb telescope’s instrument capability. He gave Batalha simulations of transiting planets to look at and challenged her to use the simulations to determine how the Webb telescope would read out transiting planet data. 

At the end of her time working with Lunine, Batalha published a paper with the Space Telescope Science Institute. The astronomical organization leads the science and mission operations for the James Webb Space Telescope. Her paper assessed the potential for the Webb telescope to characterize a type of exoplanet called super-Earths. 

Illustration: Jordan Newman

According to Batalha’s paper, previous space telescopes didn’t have the power or resolution to observe super-Earth atmospheres. Using a simulator of the Webb telescope, she determined that Webb would be able to detect water and methane in the atmospheres of super-Earths. In short, the James Webb Space Telescope would be powerful enough to expand the abilities of exoplanet research — and it could detect tantalizing signatures for life. 

Lunine says when he initially gave her the simulations, he wasn’t sure that the work Batalha did would really turn into anything significant.

“It ended up not only producing a lot, but this became Natasha’s whole career,” he says.

Democratizing astronomy

After college, Batalha moved on to graduate studies in astrophysics and astrobiology at Pennsylvania State University. There, she studied the atmospheres of other worlds, looking for planets that might be “habitable” — that is, able to support life. Batalha had to rely on software called “legacy codes,” which had been written in the 1970s and 1980s. Ever since the codes had been written they had only been shared with an exclusive inner cohort, passed down from scientist to scientist. Not only were the codes outdated and hard to access, they were also difficult to use.

Without these codes, often written in outdated software languages, other scientists couldn’t run their own computations with exoplanet data. That is, unless they knew how to program and write code themselves. 

Batalha’s experience with outmoded and exclusive codes motivated her to think about how she could change the way the field worked. 

“I just see that as so backwards,” says Batalha. “The whole point of science is to be collaborative and to share your work with people.”

Exoplanets and Webb

Only a decade or so after the difficult codes Batalha encountered as a graduate student were written, scientists began hatching plans that would dramatically change the field of astrobiology. On October 6, 1995, Swiss astronomers Didier Queloz and Michel Mayor announced the discovery of 51 Pegasi B, a small grey planet 50 light years away from Earth. It was the first exoplanet discovered orbiting a sun-like star, proving that there were planetary systems out there similar to our own. 

At the time though, astronomers couldn’t study Pegasi B and other exoplanets very closely. The Hubble space telescope, launched in 1990,  has provided incredible images of galaxies. But the telescope can only “see” objects that emit visible light. This means that Hubble is blind to other forms of energy emitted by exoplanets.

Astronomers were hungry for a new, more powerful telescope that could make more detailed observations. They wanted the telescope to be able to observe infrared waves, which penetrate through gas and dust. Such an infrared telescope would allow them to examine exoplanets more closely. With Hubble, for instance, scientists can observe basic characteristics of exoplanets. These basic characteristics include descriptions such as what they are made of and how fast they travel through space. An infrared telescope would allow them to observe other details about exoplanets, such as their temperature and the composition of their atmospheres. 

Illustration: Jordan Newman

In 1996, astronomers proposed that NASA build this new, more powerful instrument, which would become the James Webb Space Telescope. The mission, approved that year, is now poised to revolutionize our understanding of exoplanets, says Tom Greene, a NASA astrophysicist and director of the Ames Center for Exoplanet Studies. 

“It takes sometimes a fundamental new capability to make a big leap in science,” he says. “And that is what we have in James Webb for exoplanets.”

Webb has already become a cultural phenomenon. The official telescope website boasts a gallery of public artwork dedicated to Webb’s sunshield — a gossamer structure of golden hexagons.

“That surprised me, how much this has resonated with people. It’s a beautiful machine,” says Eric Smith, the Program Scientist for the James Webb Telescope. “It looks like a spaceship of the future.”

Coding the Future

Meanwhile, Batalha had earned her PhD and taken a job as a research scientist at NASA Ames Research Center. Ames had played a pivotal role in building James Webb, including designing key instruments for the telescope.

Batalha’s office at Ames is decorated by a frosted whiteboard marked up with equations and  several plants — one of which used to reside in Natalie Batalha’s office in the years when she led the Kepler mission at Ames. 

When she arrived at Ames, the younger Batalha knew she had a chance to rectify the inequity she had observed during graduate school, where she realized that only a small coterie of researchers could access critical software for analyzing exoplanets. The barrier to access primarily affects minorities and women in a field where they’re already underrepresented. 

“It’s no secret that our field is predominantly white and predominantly male,” says Batalha. “And especially being neither of those things, it’s intimidating being in a field where your success rides on having access to these tools.” 

Batalha decided to write new software to enable researchers to interpret the data returned by the James Webb Space Telescope. While other researchers advised her to limit access to her software, she ultimately decided to make it open access. Any other researcher to use the software programs that she has created: PandExo, VIRGA, and PICASO.

“At the end of the day, people will look back and see how much of the Webb science she has enabled.”

Batalha’s software programs will act as Rosetta Stones, translating James Webb’s observations into useful information for other researchers. PICASO will transform raw Webb data into readouts of exoplanetary temperatures, while VIRGA will model what the clouds surrounding exoplanets look like. 

PandExo is the most community-based of Batalha’s tools, because it was created specifically for other researchers to use. It’s been essential to researchers who are vying for observation time. The software allows users to input test data of the spectrums of planetary atmospheres and see how the Webb telescope will interpret it. Researchers around the world have used it to predict what kind of information Webb will provide, so that they can plan to make the best use of their observation time with the telescope.

Observation time on the James Webb Space telescope is limited. Parceling out time to individual researchers is akin to an economics problem, with researchers needing to figure out exactly how much time they need to get the data they want from the telescope observations.

“When you’re planning your time, you have to be really savvy,” says Batalha. “All of this time is really competitive.” She says every second needs to be accounted for. 

PandExo tells users the precision of data they will get from a given amount of time observing with the James Webb Space Telescope. With PandExo telling a researcher how much time they need to complete their observation, they can then advocate for an amount of observing time in their proposals.

Once an astronomer is able to clinch time with Webb, there’s a multitude of mysteries to explore. For one, researchers hope Webb will shed light on planet types that don’t appear in our own solar systems — planets which blur the line between gas giant and terrestrial body. 

Upcoming observations of the TRAPPIST-1 system are also hotly anticipated both within the exoplanet community and by the public. The planetary system came into prominence in 2017 when it was announced three of the rocky, Earth-like planets orbit within the system’s “habitable zone.”

Batalha plans to use her own observing time to collect data on three exoplanets, including one found in the TRAPPIST-1 System, about 40 light years from Earth. In 2017, scientists announced that three exoplanets in the TRAPPIST system might have atmospheres that could support life. Batalha plans to use data taken by the Webb telescope to look for atmospheric signatures of molecules such as water, oxygen, carbon dioxide and methane in the TRAPPIST system and elsewhere. 

“After that, we get to compare planets,” says Batalha, her tone giving away her preemptive thrill for what she might find. 

“The really interesting work will happen there,” Batalha says. 

Beyond Discovery

“When Kepler launched, we knew there were exoplanets but we didn’t know how common they were,” says Jessie Dotson, who was the Deputy Science Office Director for Kepler and is currently the project scientist for K2. 

“Now we think there’s as many planets as stars in the sky.” 

Illustration: Jordan Newman

Dotson can remember a time after Kepler’s operation began when every planet seemed precious. The first couple years they would announce just a few planet discoveries to the public. Suddenly, she says, one year they were releasing hundreds of planet discoveries.

“I remember being like, ‘whoa, that’s different,’” she says, laughing.

While the previous missions discovered the planets, they couldn’t collect much data on them. With the wavelength ranges before, an astronomer might compare it to looking at the planets through a strawhole — they could tell that they’re there, but they can’t say much about them in detail. NIRCam and the other Webb telescope instruments will allow for a wider picture.

The molecules which scientists are interested in finding in exoplanet atmospheres — such as water, oxygen, carbon dioxide, and methane — have the strongest signatures in infrared. The Webb telescope instruments will be observing the exoplanets from the longer wavelengths necessary for the detailed atmospheric characterizations which will push the field forward into new discoveries.

With the spectroscopy data provided by Webb’s instruments, scientists will essentially have the chance to peer into clouds swirling above the worlds orbiting outside our planetary system. From there, what they’ll find will begin to unravel the essential mysteries of the universe. 

After The Launch

Batalha hopes that her observations could help guide future planned missions that will look more closely for extraterrestrial life. Webb promises to be just the start of the chase to understand exoplanets. 

The James Webb Space Telescope is expected to operate for ten years. Researchers are already beginning to imagine what the 2030s and even the 2040s could hold for exoplanet research.

NASA is considering another flagship mission dedicated entirely to finding Earth-like planets which could possibly be hospitable to life. In 2019, NASA announced the establishment of its Center for Life Detection Studies.  

Jonathan Fortney, the director of the Other Worlds Laboratory at the University of California, Santa Cruz, says that a mission to find other Earth-like planets around far away stars has already garnered a lot of interest among scientists and captured the public imagination.

“Even if it ends up being extremely expensive, to me, it has almost the same allure as going to the moon,” Fortney says, his voice rising with excitement.

If twentieth century astronomy represented a chase to understand galaxies, Smith likes to think exoplanets will be the centerpiece of twenty-first century astronomy. 

“Exoplanets are going to be that piece of astronomy that drives the technology,” he says. To him, Webb is just a fulcrum — finishing one cosmic chase and paving the way for the start of another.

Thinking of December’s launch inspires nostalgia for Smith, who has worked on the telescope since it was just the initial sketches on a whiteboard. “It’ll be like when I sent my kids off to college.”

“It has been the project of a lifetime.”

If Smith sees the culmination of his career in the James Webb Space Telescope launch, for Batalha it’s just the beginning. 

“Even starting from our own solar system, there’s so many questions that we want answered,” she says.

A big motivation for exoplanet research is to understand the origins of life, specifically if life can exist on other planets. 

However, “You have to understand the full picture before you go at that one question,” Batalha says of the greater existential question of life on other planets. “You have to understand the broader context of how planets form, how they evolve.” 

Even after the James Webb Telescope launch, Batalha and the other rising exoplanet scientists will have decades of work ahead of them unraveling the minutiae of planet characteristics. There’s so much more to discover and the Webb telescope will place a firm foot forward for astronomers everywhere.

“We’re gaining huge ground in understanding our place.”

© 2021 Allison Gasparini / UC Santa Cruz Science Communication Program