Kicking off a new era for astronomy, the new views of stars, galaxies, and nebulae push human understanding deeper into the universe.
JULY 12, 2022
GREENBELT, MARYLANDThe first full-color images from NASA’s sharpest eye in the sky, the flagship James Webb Space Telescope, were unveiled to the world today from the space agency’s Goddard Space Flight Center in Maryland. A packed auditorium greeted each image as it was unveiled with cheers, oohs, and ahs.
The telescope’s first image was revealed Monday evening at the White House by U.S. President Joe Biden. It depicts a pocket of space populated by ancient galaxies, representing the deepest-ever view of the cosmos.
“It’s really gorgeous, and it’s teeming with galaxies. That’s something that has been true for every image we’ve gotten with Webb. We can’t take blank sky—everywhere we look there’s galaxies everywhere,” says NASA’s Jane Rigby. “There’s a sharpness and a clarity we’ve never had.”
The others, unveiled July 12 at Goddard, capture snapshots of curvy, colliding galaxies; the diaphanous ring blown by a dying star; the atmospheric spectrum of a hot, Jupiter-like exoplanet; and the radiant, chaotic clouds engulfing a stellar nursery.
“I am so thrilled and so relieved, this was so hard,” says NASA’s John Mather, JWST’s senior project scientist. “It’s just impossible to convey how hard it really was. We risked so much to say we’re going to go do this, and it’s so near impossible.”
These first full-color images showcase JWST’s capabilities and span the breadth of science instruments aboard the observatory. Their release also marks the beginning of official science observations, which in the telescope’s first year will focus on ancient galaxies, faraway alien worlds, the life cycle of stars, newborn planets, and celestial bodies in our own solar system.
For the team behind the pictures, pulling back the universe’s curtain and drinking in the new cosmic light was a moment of profound significance. These first images are fresh views of the cosmos through an entirely new set of eyes—images that, in addition to being beautiful, symbolize JWST’s power to revolutionize our understanding of the universe and our place within its boundless cosmic sea.
“You feel like the sky is opening up, and you’re in a moment of time and space that you’ll forever remember because you saw the universe as nobody has seen it yet,” Thomas Zurbuchen, NASA’s associate administrator for the science mission directorate, told reporters on June 29, before the images were released.
“It’s really hard to look at the universe in a new light and not have a moment that is deeply personal in a way that, frankly, surprised me.”
Capturing the cosmos
The first science images from JWST mark the end of a six-and-a-half month deployment routine. After launching in December 2021, the telescope flew to its destination a million miles from Earth, unfolded in space, and powered up its instruments. Perched in its final orbit, JWST can now do what it was built for: search the universe, both in space and in time, for things never seen before.
The deep-field image, which reveals a seemingly bottomless pit of galaxies, is the deepest image yet of the cosmos. Some of those galaxies, whose light is warped and stretched by the immense gravity of a cluster of galaxies in the foreground, are seen as they existed more than 13 billion years ago.
“You just know it’s ancient, ancient light. It’s been traveling across the universe for billions of years and just so happened to bounce off of Webb’s mirror and make its way to Earth, and now it’s on my desktop," says the Space Telescope Science Institute’s (STScI) Joe DePasquale, who processed these initial images.
Scientists have also been able to discern the chemical elements comprising at least one of those galaxies. “This is how the oxygen in our bodies was made—in stars, in galaxies, and we’re seeing that process get started,” Rigby said at the release event.
In another image, a riotous stellar nursery about 7,600 light-years away blazes in the southern sky. Called the Carina Nebula, it shrouds a region of intense star formation that is also home to the massive, perplexing stellar object Eta Carinae—a beast so immense that some astronomers say it’s pushing the limits of what it means to be a star. “There’s so much going on here, it’s just beautiful,” says NASA astrophysicist Amber Straughn, pointing to bubbles, cavities, and jets within the nebula, newborn stars that have never been seen before, and galaxies lurking in the background.
Representing the opposite end of the stellar life cycle is the Southern Ring Nebula. About 2,000 light-years away and spanning half a light-year, the nebula is a poignant, tenuous mark of stellar mortality: the puff of gas and dust exhaled by a dying star.
JWST also captured Stephan’s Quintet, five galaxies about 290 million light-years away, four of which are locked in a swirling, cosmic dance. Two of those galaxies are merging, heating heaps of gas and dust and fueling new starbirth.
And completing the first image release is a spectrum of the exoplanet WASP-96b, a giant world about 1,150 light-years away that orbits its star every 3.4 days. In that spectrum are signs of the planet’s atmospheric composition, as well as information about clouds and hazes.
“What you can see here is a telltale signature, the chemical fingerprint of water vapor in the atmosphere of this specific exoplanet, “ says NASA astrophysicist Knicole Colón. “There’s a lot more to come.”
Assembling the cast
Until a few days before their release, JWST’s first full-color targets were a closely guarded secret—a mystery that ignited anticipation and fueled betting pools among astronomers. Then on July 8 the space agency published the target list—all of them, somewhat coincidentally, are in Earth’s southern skies.
“We will of course look at the northern sky too,” Zurbuchen told National Geographic.
The process of selecting the targets took years, says STScI’s Klaus Pontoppidan. A small committee initially came up with more than 70 potential targets, chosen for their aesthetic and scientific value, and for their suitability to be highlighted by JWST’s science instruments. Later, the team removed objects that overlapped with projects slated for JWST’s first year of science operations. Then it was a question of serendipity—seeing which targets were visible after the telescope completed half a year of preparations to begin observations.
“It’s been a long process,” says Pontoppidan, who led the image production team. “But also, just knowing you’re seeing something for the first time—there are very few people in the world who can see something for the first time. We feel so privileged.”
After the telescope beamed the images to Earth, STScI’s DePasquale and Alyssa Pagan got to work processing them: calibrating the information from different instruments, considering how to frame the objects, and applying color. JWST sees the universe in infrared wavelengths, which are longer than human eyes can perceive, so DePasquale and Pagan applied a palette that corresponds to the colors we do see: Longer wavelengths are red, green is intermediate, and shorter wavelengths are blue.
As impressive as this first handful of images is, Pontoppidan and DePasquale promise that more will be released soon. DePasquale says his favorite among JWST’s early targets has yet to be revealed—an object that captivated him while he processed and colored it.
“It was so impressive,” he says. “Every once in a while, I would take a deep breath, sit back, bring my head out of the pixels for a minute, look at the whole image. And I just felt this overwhelming sense of awe and wonder, and I felt extremely fortunate to be here, at this moment in time.”
Reveling in insignificance
Seeing these new views of the universe in all its magnificence, depth, and grandeur can be an almost transcendent experience, says Stanford University’s Elizabeth Kessler, who studies the aesthetics of astronomical imagery.
“There’s a long, well established tradition of thinking about looking up at the stars and the ways that encourages us, as humans, to reflect on our place in the cosmos, our relative insignificance, its vast size, how much there is to know,” she says. “All of that might make us feel very tiny, but it also reminds us: Wow, we actually can gain some level of insight, some level of knowledge.”
Kessler likens it to the body of artwork depicting awe-inspiring landscapes of the American West—places like the Grand Canyon, Yellowstone, and Yosemite that are now national parks. DePasquale is also reminded of those 19th-century landscapes, particularly when he looks at the image of the Carina Nebula. “It’s so vibrant, and the colors pop so much.”
Seeing the universe in a new light while reveling in discovery and appreciating the immensity of the unknown is almost exactly what German philosopher Immanuel Kant described in the mid-1700s as the experience of the sublime: an encounter, often with something in nature, that one can understand rationally but cannot fully imagine, leading to a simultaneous sense of frustration and appreciation for the magnitude of the phenomenon.
What sets the sublime apart from merely being awestruck, Kessler says, is contained in the roots of the word itself—a term borrowed from chemistry. “It’s a movement from one state to another,” she says. “And that connects to the very ways in which something like JWST is showing us what’s beyond our vision.”
When taking in the beauty of the Southern Ring Nebula, or the eye-popping number of galaxies in the deep-field image, or the chaos of cosmic collisions in Stephan’s Quintet, one confronts a new understanding of the immensity of reality.
“This is really our story up there,“ Zurbuchen says. “There is no way of explaining and understanding our life—who we are today, how we’re built, without looking at the stars. Because that’s where our story is, a story that started at the beginning of the universe.”
(Sources: National Geographic)
Đăng nhận xét