As an astronomer with the Space Telescope Science Institute at Johns Hopkins University, Christine Chen spends her days poring through research proposals from the world’s astronomers and astrophysicists—all eager for time on NASA’s new James Webb Space Telescope (JWST), considered the most powerful technology of its kind in history. Launched on December 25, the $10 billion telescope, now hurtling through space to a destination one million miles away, promises to answer questions about the origins of our universe.
What most excites you about the telescope?
JWST will probe farther back in time than any other instrument to see the first stars and galaxies that formed after the Big Bang. The universe is expanding, and these distant galaxies are flying away from us at tremendous speeds. With the telescope’s use of infrared wave lengths, we can peer into these galaxies at the edge of time and advance our understanding of galaxy evolution—and how the universe evolved from those first galaxies 100 million years after the Big Bang to the galaxies we see today.
We’ll also learn a tremendous amount about exoplanets, or planets outside our solar system that orbit a star, and the composition of their atmospheres. This field has grown immensely since astronomers discovered the first exoplanet in the mid-1990s. Since then, we’ve discovered more than 4,000, which has led to exponential growth in our understanding of planets. With JWST, that growth will continue to expand our knowledge, likely in a mindboggling way.
For example, we might learn what happens, say, on an extremely hot planet with a temperature of 1,700 kelvin, or 2,600.33 degrees Fahrenheit, versus planets with temperatures more like Earth, at 300 kelvin, or 80.33 degrees Fahrenheit. At 1,700 kelvin, silicates condense to make up the mineral olivine and gemstone peridot—deposits that cause the green sand beaches of Hawaii. So, we can imagine that there might be green clouds of peridot on these planets or something totally unlike what we see on Earth.
The international astronomy community awaited the launch of JWST for a long time. Tell us about the wait—and how it feels to have the telescope off the ground.
When I joined the mission in 2008, JWST was scheduled to launch in 2014 but ran into a whole series of setbacks. One challenge involved the telescope’s enormous sun shield. Made of five thin layers, each the size of a tennis court, the sun shield launched in a folded position and needed to unfurl in space, with hundreds of motors and actuators syncing to make it happen. When they tested it on the ground, the sun shield tore, and they had to patch it. This, in itself, caused a number of delays. On December 31, 2021, the sun shield deployed successfully in space. Now that we’re a few months in, we’re past the big milestones involving scary engineering. We can breathe a huge sigh of relief—and just get excited about the work of tens of thousands of people’s efforts coming to fruition.
With scientists worldwide clamoring to use the telescope for research purposes, how do you decide who uses JWST?
JWST is an “open skies telescope,” which means anybody can submit a proposal to use it, and data collected will be shared with the world as soon as possible so everyone can analyze and learn from it. But the telescope is in high demand, and time is limited. We use a double-blind peer-review process to remove bias from our proposal selection. This means we don’t know the scientist or institution submitting the proposal—a process that, we hope, will enable younger people and smaller institutions, not just the big R1 research institutions, to be more successful proposers. Another goal is to lower the success rate disparity between men and women.
How does it feel for you personally to be at the center of such a bold endeavor?
It’s tremendously exciting to work with the forward-thinking optimism that comes with everyone daydreaming about how our findings will revolutionize our understanding of the universe. It’s easy to get lost as a scientist, with your head down in analysis. But this reminds us that science is a human endeavor that pushes the frontier of knowledge.
We have to ask: do you expect to find life?
I think we’ll take a step in that direction, but I worry about people setting their expectations that we will definitively find life. It’s safe to say we’re looking for what we know are astrobiological-relevant molecules [which signal life] in these planets, but planets in their unique atmospheres are complex systems, and interpreting what we find will be complicated. Take, for example, when they searched for life in our own solar system and sent the Viking landers to Mars in the 1970s. They discovered that the chemistry of the planet was totally different, so the experiment they designed to work on Earth didn’t work on Mars. The challenge will be getting past ourselves and our limited experience with only one way of life. The universe has so many unimagined possibilities.
When can the public expect to see the first images?
Six months after the launch, at the end of June, NASA will share what they call “early release observations” to give everyone a flavor of the kinds of images and information JWST can generate. We can expect to see some gorgeous, newsworthy pictures at that time, while getting a sense of what’s to come.