NASA’s new telescope is worth every penny
Despite its $10 billion cost, the Webb will revolutionize cosmic understanding
I’ve been eagerly looking forward to the first images from the James Webb Space Telescope for more than a quarter century now. It was in 1996, when I was working on a book on the search for life in the universe, that I first heard about this extraordinary new observatory from John Mather, the NASA scientist in charge of the project. Back then it was known, more generically, as the Next Generation Space Telescope, planned as the bigger, more powerful successor to the Hubble Space Telescope. It would cost a half-billion dollars, Mather predicted. It would launch into space in 2005. And it would help astronomers answer such fundamental questions as how and when the first stars burst into light after the Big Bang; whether planets that circle distant stars have life-friendly atmospheres; and what kinds of objects orbit at the frigid edge of our own solar system, out beyond Pluto.
At the time, the price tag and launch date seemed overly optimistic (in the end, the telescope wouldn’t launch until 2021, with a price tag of more than $10 billion). But I didn’t doubt his promise of great discoveries, since I’d seen the same sort of thing happen since I first became entranced with the cosmos back in the 1950s. My father was a physics professor at Princeton University — an accomplished scientist, but more importantly for a small child, a great storyteller.
Some of my earliest memories were of him taking me outside at night, pointing to the moon, the planets, the stars, and telling me stories of ancient philosophers trying to understand what they were. He told me of how people like Isaac Newton, Johannes Kepler, Nicolaus Copernicus and Galileo Galilei had begun to appreciate the true nature of these mysterious objects, and how telescopes had let their successors build on this understanding — and were continuing to do so.
I was utterly hooked — not just by the grandeur of the cosmos my father revealed to me, but also by the fact that there was no shortage of mysteries still to understand. When he started telling me these stories, scientists had
still never laid eyes on the far side of the moon. Their sharpest images of the planets, photographed through Earth’s blurring, shimmering atmosphere, were too fuzzy to make out any details. By the early 1960s, astronomers had discovered bizarre objects they called quasars — to all appearances, just ordinary stars, but so far away that they had to be as luminous as entire galaxies to be seen from Earth. They knew the universe was expanding, but didn’t have any definitive evidence that it began with a Big Bang. They didn’t know whether planets orbited any stars beyond the sun. They thought Pluto marked the outer edge of our solar system.
One by one, however, those mysteries were solved. A Soviet probe photographed the far side of the moon, followed by other probes, followed by Apollo astronauts who photographed it in great detail ( it looks very different from the side we see). Robotic orbiters began imaging Mars at high resolution, while rovers wheeled across its surface; we discovered that Mars had oceans of water in the distant past, and maybe even hosted life. The Voyager and Pioneer spacecraft took closeups of the outer planets on flybys, and the Galileo and Cassini went into orbit around Jupiter and Saturn, respectively. Now we know that some of the moons of these giant worlds hide gigantic oceans beneath their frozen surfaces. We learned that quasars are actually powered by giant black holes at the cores of distant galaxies, whose irresistible gravity sucks in surrounding matter and heats it to extraordinary temperatures. We learned that Pluto is merely the brightest member of a gigantic swarm of icy objects, known as the Kuiper Belt; essentially construction debris left over from the building of the solar system more than 4 billion years ago. And we learned that planets orbit most of the tens of billions of stars in the Milky Way.
All of this and more came as astronomers imagined and built more and more powerful telescopes, not just capable of seeing visible light but also its close cousins: radio waves, microwaves, infrared and ultraviolet light, X-rays and gamma rays, all of them otherwise invisible to the human eye. They also built instruments that can detect neutrinos — subatomic particles so elusive that they can pass right through the Earth without slowing down — and gravitational waves, which are ripples in the fabric of spacetime predicted by Einstein but only confirmed in 2015.
These advancements all led to major discoveries about the universe we live in. And with a track record like that, I had no doubt that the new telescope John Mather was telling me about would make extraordinary discoveries as well. Some would help answer the questions we already have about planets, stars and the nature of the early universe. But perhaps even more exciting, he said, the new telescope would inevitably raise unexpected questions about the cosmos that we currently don’t even know enough to ask.
When my father first started telling me stories about the universe, he didn’t mention dark matter, which outweighs the familiar stars and galaxies by a factor of six or so. He didn’t mention dark energy, which is making the universe expand faster and faster all the time. Both were fringe ideas at the time that few took seriously. Same for the Big Bang — less fringe, but far from being widely accepted. Now, thanks to new instruments that allow us to see the cosmos more clearly than anything available in the 1950s, we know they’re almost certainly real, and astrophysicists are actively struggling to understand them more deeply.
That’s why, despite the fact that the Webb telescope cost so much more and took so much longer than Mather imagined (and that its mirror is smaller and less powerful than he hoped it would be), I haven’t the slightest doubt that it will live up to its most important promise: that it will revolutionize our understanding of the cosmos, in ways we can’t yet predict.
The extraordinary new images released by NASA a few days ago demonstrate how much more powerful the Webb is than the Hubble. One shows a field of galaxies in glittering focus, including some of the faintest, and thus most distant, ever seen. Another peers into a nearby planetary nebula, a huge blob of glowing gas thrown off by a dying star, to uncover a second star that hadn’t been seen before. Yet another looks at the other end of stellar life cycles, unveiling the secrets of a cloud of gas and dust where new stars are even now being born.
But perhaps most significantly, one image isn’t a photograph of an object: it’s a graph that shows the presence of water in the atmosphere of a distant planet known as WASP-96 b. This sort of thing is why the James Webb Space Telescope will inevitably revolutionize astronomy. Spectacular images inspire awe and wonder, but it’s when the Webb probes deeper that it will tell scientists what’s actually going on in those young galaxies, shimmering clouds and faraway planets.
Is all of this really important? Is it worth the $10 billion? Obviously not in the sense that it will immediately save lives or help fight climate change or make the economy stronger or make our smartphones smarter.
When people raise such questions — and they do — I’m reminded of what the physicist Robert Wilson said during a 1969 Senate hearing on whether the government should fund a multimillion-dollar accelerator outside of Chicago to study the nature of subatomic particles. One senator asked, naively, if it would contribute in any way to the national defense.
Wilson’s answer: No.
“It has only to do with the respect with which we regard one another,” he said, “the dignity of man, our love of culture. It has to do with: Are we good painters, good sculptors, great poets? I mean all the things we really venerate in our country and are patriotic about. It has nothing to do directly with defending our country except to make it worth defending.”