Since its launch, arguably the roughest luck the James Webb Space Telescope has had is hitting a micrometeoroid the size of a grain of sand. But, of the three hundred and forty-four details that were once listed as things that could go wrong and destroy the whole mission, none has happened. On July 12th, the first five scientific images taken by the telescope were released to the public. The level of detail has far surpassed expectations. These images carry news about the early universe, the birth and death of stars, the collision of galaxies, and the atmospheres of exoplanets. (Exoplanets are ones not in our solar system.) And they’re very, very pretty. The smudgy-pastel feel that previous telescopes delivered is not present. The sharpness and clarity might make you think of Vermeer—what is being painted is light.
“I am beyond cloud nine,” the astrophysicist Marcia Rieke told me. Rieke has served as the chief scientist for one of the telescope’s main instruments, the NIRCam; her husband, George Rieke, has been the chief U.S. scientist for another instrument, the MIRI. Marcia’s team looks at some of the shortest wavelengths that the telescope can perceive, while George’s team looks at some of the longest. There was always a possibility that the highly complex J.W.S.T. would disappoint, or fail altogether. “Now I feel like the young people who worked on this project—they have a bright future in astronomy,” Marcia said.
Marcia Rieke had an opportunity to see the first images a few days before they were released, because she was asked to make a short presentation to help interpret them. The first one, called a deep-field image, is of a patch of sky that, from Earth, is about the equivalent of what would be occluded by a grain of sand—or a micrometeoroid—held out at arm’s length. The Hubble telescope, which focussed on a similar patch of sky for two weeks, revealed thousands more galaxies than expected. The new image, which took less than a day to make, shows immensely more detail—and more galaxies. “No matter where we’ve pointed J.W.S.T., even in the images taken during commissioning that would last a few tens of seconds, we kept getting these galaxies that we weren’t even looking for in the background,” Rieke said. She said that the team started to term these incidental galaxies “photobombers.”
Rieke was surprised by how moved she was by the beauty of the pictures. “I knew computationally that the diffraction was limited to a micron, that the full width at half maximum was whatever—I knew we’d have pretty pictures,” she said. “I didn’t expect them to be so absolutely stunning. You know, if you start out in life as a ground-based astronomer . . . this is not the level of detail you’re used to being able to see.”
After her surprise subsided, she began to look at the galaxies that appeared the reddest. Their light had been travelling the longest—sometimes for more than thirteen billion years. This means that they are being seen as they were not too long after the Big Bang. They hold information about how the earliest galaxies were formed, and of what elements they consisted. “Now that we have the image, we go through the process of measuring, quantitatively, how bright every spot is with every filter that you measured with,” she said. “Then you can get an instant estimate of how far away that galaxy is.”
A list of the most interesting or unusual galaxies was put together. “And what is interesting depends on who you are,” she said. “Maybe you’re interested in the most distant galaxy. Or the one that shows a black hole.” Then another J.W.S.T. instrument, NIRSpec, can give data that open up other lines of inquiries: How many heavy elements or metals are there in that galaxy? Or is the galaxy so young that those heavy elements haven’t had time to form? In September, a longer exposure of a deep field that is represented in a famous Hubble image will be taken—ten times longer—which will bring news of even earlier, and therefore fainter, light. This light will be coming from even closer to the earliest moments of our universe—“when the first little aggregates of stars have come together,” Marcia said.
Each of the five images had its own “Easter eggs,” as one of the astronomers who presented the images live on a NASA stream put it. One, of a dying star sending out waves of energy, revealed a second star nearby, which the dying star was orbiting. Little rays of dying starlight were escaping from the clouds of dust, just as sun rays might pierce through clouds. In the image of the exoplanet WASP-96b, water vapor was seen. In the image of the Carina Nebula—a birthplace of stars—a dark billow in the cloud of dust and ionized gas presented a mystery.
Rieke feels that these images are the beginning of getting to pay back to the public the money—some ten billion dollars—that was spent on the J.W.S.T. “For pragmatists, one might think, O.K., Webb can study exoplanets in great detail,” she said. “We can, for example, look for evidence of climate change on an exoplanet and study that, since we don’t have other examples in our solar system where we can look at the effects of carbon dioxide and other gases.” But Rieke is clearly more persuaded by other kinds of gains. “People need hope and challenges. And people need the spice of discovery.” She said that, for scientists, these images bring a sense of scale. “What does it mean to know our place in the universe? You can say, ‘Who cares?’ But, if we really want to understand the universe, we need to know at least how it works.”
Some people might find the level of detail in the images less like a Vermeer and more like a Hieronymus Bosch—everywhere you zoom in, you get an image that is frightening, alien, or sublime. There’s something vertiginous and confusing about taking one’s life seriously, until a new sense of scale alters that perspective. I spoke with Rieke while travelling with my daughter, who made an observation about our hotel room that I found relevant to, well, cosmic beauty. “You know what I like about small hotel rooms?” she asked. I didn’t know. “There’s less there to be scared of in the dark.” Of course, such experiences of scale can be comforting at other ages, too.
I asked Rieke about an idea related to what’s called the Drake equation. How likely is it that there are other civilizations out there, and how many might there be? Some have used the equation to say that it’s almost certain that there are stories a long time ago and in galaxies far, far away. Others have solved the equation to say, basically, no. Rieke said, “I feel pretty confident that Webb will at some point identify an exoplanet in the habitable zone. A place that’s nice and comfy, with an atmosphere whose composition is like Earth’s.” But, she said, even with input from biologists and chemists, there’s “still a lot of controversy over what might be evidence for the suggestions of life.” ♦