We Have One Shot to See the Universe Like Never Before
Days from now, the James Webb Space Telescope will launch and unfold a whole new view of the cosmos. That is, if it actually works.
In the beginning, the universe was dark. The Big Bang had electrified the cosmos into existence, and the new landscape buzzed with particles, chaotic and hot, before cooling off into a calm expanse of hydrogen and helium. Then something began to happen in the fog. Gravity drove pockets of gas to collapse in on themselves and ignite, creating the first stars. The radiant orbs began to cluster, forming the first galaxies: messy, misshapen things, not as polished as our Milky Way today, with its elegant spirals. But the young galaxies cast their sparkle into the darkness, illuminating the universe. They must have been beautiful.
Astronomers have studied this early epoch with telescopes on the ground and in space. They have detected some ancient galaxies, capturing them as they appeared billions of years ago, when the photons peeled off the surfaces of their stars and wafted across the universe. Still, there are whole chapters missing. We don’t really know, beyond those broad outlines, how or when the very first stars and galaxies came to be. Scientists have done what they can, stretching existing telescopes to their limits and filling in the gaps with theoretical models. But they know that there’s more primordial light out there, streaked with answers to some of humanity’s most existential questions. They just need a new kind of instrument to help them look even deeper.
That instrument is almost ready. The James Webb Space Telescope is currently sitting on top of a rocket in South America, surrounded by technicians obsessively checking every bit of it. Launch for the $10 billion observatory is currently scheduled for December 24, Christmas Eve. Webb, the product of a collaboration between three space agencies, is 100 times more powerful than its predecessor, the Hubble Space Telescope. While Hubble’s “deep field,” the famous shot featuring thousands of galaxies, could fit on a standard sheet of paper, Webb’s equivalent would be so expansive, one astronomer told me, that it would need to be printed on wallpaper. This time, the shot would reveal 1 million galaxies, including some of the earliest.
Webb will look, too, at far more than just the first sparks of the universe. It’s an all-purpose telescope that can observe the planets and moons in our solar system, our asteroids and comets; inspect planets that belong to other suns and planets that don’t belong to any star at all; study tiny particles of interstellar dust and gaping, supermassive black holes and mysterious luminous objects called quasars. This is the telescope that wants to capture, well, nearly everything.
It sounds almost greedy. But it’s the good version of greedy. This new space venture doesn’t involve a nation trying to beat its rival to the moon, or space billionaires comparing their rockets (or arguing over whose internet satellites are better, or feuding over who gets to build the next lunar lander). The Webb observatory certainly has its own earthly problems, such as schedule slips, budget overruns, and a controversy over its namesake, a former NASA administrator from the Apollo era. But the project, at its core, represents some of our purest intentions in space exploration. Scientists want to understand the arc of our strange universe, how it led to a story of life on Earth, and whether that narrative has unfolded anywhere else. They want to capture the light of celestial objects and pick it apart the way raindrops bend sunlight into a rainbow, and learn what they’re made of, whether they’re something as familiar as Mars or as mysterious as a primordial star. And the pictures should be pretty great too.
Scientists have had plenty of time to dream up their plans for Webb. The observatory has been in the works for 25 years—even longer if you count the years since NASA first imagined the ambitious concept. By now, astronomers have wrung nearly every discovery they can out of their beloved Hubble, still collecting whatever the universe sends its way after more than 30 years in operation. They’re eager to see the universe with a much bigger telescope, and in a whole new light—literally. While Hubble observes the universe in mostly visible and ultraviolet light, Webb will scan in infrared light, which can pass more easily through matter. NASA likes to demonstrate the difference between visible and infrared wavelengths using images of a nebula—a formation of interstellar clouds—located several thousand light-years from Earth. In Hubble’s view, the nebula is gorgeous but hazy, most of its stars hidden behind colorful dust. In a simulated Webb view, the dust is gone, and countless stars shine like jewels.
Cosmic veils like these are draped all over the universe. Naomi Rowe-Gurney, an astronomer at NASA’s Goddard Space Flight Center, is particularly interested in what Webb can show her about two of the most overlooked planets in our solar system, Neptune and Uranus. “We really know nothing about the ice giants at all,” Rowe-Gurney told me. Existing telescopes can’t penetrate the planets’ cloud tops, but with Webb, “you’re going to be able to see through all of that haze, and be able to see what’s happening inside the atmosphere,” Rowe-Gurney said. Webb can detect the intricate chemistry, even the weather, brewing beneath the icy clouds.
And in places where we have had a clear enough view of the big picture, Webb will be able to capture new details. The mission will explore two of the most intriguing moons in the solar system, Europa and Enceladus. Europa, which belongs to Jupiter, and Enceladus, to Saturn, are both frigid worlds, frosted over with ice. But Hubble and other spacecraft have captured plumes of water vapor and organic compounds shooting from cracks in their surface, suggesting hidden oceans churning within. Astronomers love oceans; under the right conditions, and with the right molecules, they’re a lovely place for tiny organisms to emerge. They plan to use one of Webb’s sensitive instruments to analyze the composition of these plumes as they spot them. “We’re not going to detect life itself, but the idea is to look for a chemistry that’s maybe not anticipated,” Stefanie Milam, the Webb mission’s deputy project scientist for planetary science, told me. Weird chemistry signals the presence of something we don’t understand, and can keep astronomers occupied for years, trying to tease out whether that something is a plain abiotic phenomenon or a hint of a funky alien life form.
Astronomers plan to take that question beyond our solar system, directing Webb’s gaze toward exoplanets, which hadn’t been discovered yet when Hubble launched in 1990. Astronomers have discovered more than 4,800 exoplanets, but they’re only just now beginning the work of exploring their atmospheres. Webb’s instruments are capable of peering through alien air, and even checking if those atmospheres have the same molecules as our own does. Nikole Lewis, an astrophysicist at Cornell, is eager to try this out on a system of seven rocky, Earth-size worlds about 40 light-years from Earth. “Getting any information in terms of what’s in the air of these planets will help us to start to think about how those atmospheres formed—and if those atmospheres are being perturbed by life,” Lewis told me.
All the while, astronomers will be thinking deeply about those first chapters, approximately 13.8 billion years ago. The Webb telescope’s prime objective has always been to capture that first light, which has become so stretched on its journey across the expanding universe that, by the time it reaches us, it can’t be seen in visible light, only in the heat of infrared. The most distant galaxy that Hubble has detected existed 500 million years after the Big Bang. Astronomers believe that galaxy formation began earlier than that, and they think Webb can see that far back, possibly to just 100 million years after the explosive moment. And they think that it can not only see the galaxies from that time, but also discern what they’re made of, says Steve Finkelstein, an astrophysicist at the University of Texas at Austin. “We can actually make detailed measurements of how much of every chemical element is in these distant galaxies,” Finkelstein, who is leading the effort to create a Webb deep field, told me.
A hundred million years sounds unfathomably long in our own perception of time, but it is a nearly imperceptible flash on cosmic scales. The thought of reaching toward that edge made me briefly uncomfortable; it seemed to me like the Webb mission—and, by extension, humanity—was encroaching on something almost sacred, too cosmically divine for a bunch of Earthlings to witness. We can’t see all the way back to the Big Bang itself or the immediate aftermath—before those first stars blinked on, there’s really nothing to see—but Webb’s reach seemed close enough. When I told Rohan Naidu, a Ph.D. student at Harvard who will be among the first users of the Webb telescope, about this, he laughed, and then gave me a classic scientist response. For Naidu, Webb is one notch in a long tradition of expanding human knowledge, its mission not so different from that of the first explorers to traverse Antarctica. “Eventually, we made it to the moon, and then after that, we made it to the edges of the solar system. Then we peered through Hubble and found these very distant galaxies.” Now it’s Webb’s turn.
It's possible—probable even—that Webb will uncover something that no one expected, the finding that rewrites everything. The Hubble deep field? That was an enormous surprise. It came about only because the director of the institution that managed Hubble decided to use the perks of his position to point the telescope at nothing for hours, just to see what might pop up. In fact, his colleagues told him that it was a bad idea and tried to discourage him. Finkelstein, the scientist preparing to make Webb’s version of a deep field, said astronomers are ready to have their predictions warped. “We could make a guess, Okay, I think we’ll do this, I think we’ll see that—but we simply don’t know,” Finkelstein said. “We’re looking at the universe in a new way, and we don’t know what we’re going to discover.”
There is, of course, a very real, horrible chance that Webb won’t work.
The new observatory is one of the most complicated pieces of engineering in history. It makes a Mars rover look like a toy car. Every piece of Webb has been tested and retested over the years, and the NASA engineers in charge of the effort say that they feel confident about the mission, even as some last-minute troubles have come up in the final weeks before launch, at Webb’s final stop on Earth, on the coast of French Guiana. Since early November, technicians have dealt with a rogue clamp and a malfunctioning cable, adding delays to the launch schedule. “Once a spacecraft sits on top of a rocket, you want to get it off this planet as soon as possible after you do all the checks,” Thomas Zurbuchen, NASA’s associate administrator for science missions, told me last week. The statement suggests that after launch, it’s smooth sailing for Webb. But oh no. No, no, no. Launch, for this mission, is the easy part.
In the weeks after blastoff, Webb must undergo the most complicated robotic deployment in the history of space exploration. Too big to fit inside any existing rockets, Webb will leave Earth folded up and then unfurl piece by piece. The process has more than 300 elements known as “single-point failures” that, if they don’t work as intended, could jeopardize the entire mission. So much has to go right, and so little can go wrong. No one expected Hubble to launch with a defective mirror that blurred its view of space, but it did, and NASA was forced to send astronauts up there to fix it. The stakes are much higher this time. Hubble orbits 340 miles above Earth, and was designed to be visited. Webb will orbit a million miles away, well out of reach of human hands.
“It would be crushing,” Jeyhan Kartaltepe, an astrophysicist at the Rochester Institute of Technology whose team received the biggest chunk of observing time in Webb’s first year, told me. “I don’t think I can even express how crushing it would be.” When the public learned that Hubble wasn’t working, the telescope became fodder for late-night television hosts, particularly Jay Leno. If the worst happens, Webb could become a piece of junk in space, and a punch line on Earth.
If it works, Webb could someday become as well-known as Hubble, synonymous in the public imagination with dazzling pictures. NASA, which developed Webb’s special infrared camera, is being secretive about which photos from the mission will be publicly released first when the observatory finishes its lengthy deployment and begins operations next year. There will be no photos of Earth from a distance, no Sagan-esque “that’s home, that’s us” moment. The telescope’s mirrors will be perpetually oriented toward space, away from the sun, Earth, and the rest of the inner solar system. (Sorry, Venus and Mercury!) But even without looking directly at us, Webb will be reading out the story of our beginning. Some of the first stars burned out quickly, bursting in supernovas that forged heavier elements than the hydrogen and helium that permeated the early universe. These supernovas and other phenomena spun across the solar system, infusing the landscape with the cosmic fragments that eventually shaped planets and moons, shaped us. Beryllium, the light metal used to make Webb’s mirrors, forms in the interstellar medium, rather than through a supernova, but in a trippy sense, the Webb observatory is a very sophisticated collection of stardust looking back at itself. As if human beings took some of the finest elements in the universe, assembled them together, and then turned them back at the void to say, Look. Look what we made with what you gave us.
In the end, Webb—if it succeeds—could provide what I’ve come to think of as “from now on” moments. There’s a great scene in the movie Apollo 13, about a nearly disastrous mission to the moon, where the NASA astronaut Jim Lovell hosts a watch party at his home for the first moon landing, Apollo 11, in 1969. After the guests watch Neil Armstrong climb down the lunar lander and step onto the surface on a grainy black-and-white television, Lovell says, “From now on, we live in a world where man has walked on the moon.” Space exploration since has been in pursuit of more occasions like this. Landing a spacecraft on Mars, discovering the first exoplanet, seeing so many galaxies with Hubble—these were all “from now on” moments, junctures that shifted our perspective on our place in the universe. Astronomers have waited years for Webb, and they’ve set themselves up to make new discoveries, prepared to be right, or wrong, or stunned. We can try to see everything, but we can’t know exactly what we’ll find.