By Dennis Overbye, Kenneth Chang and Joshua Sokol
The universe was born in darkness 13.8 billion years ago, and even after the first stars and galaxies blazed into existence a few hundred million years later, these too stayed dark. Their brilliant light, stretched by time and the expanding cosmos, dimmed into the infrared, rendering them — and other clues to our beginnings — inaccessible to every eye and instrument.
Until now. On July 12 the James Webb Space Telescope, the most powerful space observatory yet built, offered a spectacular slideshow of our previously invisible nascent cosmos. Ancient galaxies carpeting the sky like jewels on black velvet. Fledgling stars shining out from deep within cumulus clouds of interstellar dust. Hints of water vapor in the atmosphere of a remote exoplanet.
Their sum is both a new vision of the universe and a view of the universe as it once appeared new.
“That was always out there,” said Jane Rigby, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the telescope’s operations manager. “We just had to build a telescope to go see what was there.”
The Webb telescope — NASA’s vaunted successor to the Hubble Space Telescope, 30 years and nearly $10 billion in the making — is equipped to access this realm of cosmic history, study the first stars and galaxies and look for nearer, potentially habitable worlds. It is a collaboration among NASA, the European Space Agency and the Canadian Space Agency.
“We’re looking for the first things to come out of the Big Bang,” said John Mather, senior project scientist for the telescope.
President Joe Biden offered a preview a day earlier when he introduced what NASA officials and astronomers hailed as the deepest image yet taken of the cosmos, a mark that will probably be passed before the week is done as more data spews forth from NASA’s computers.
The image, of a distant star cluster called SMACS 0723, revealed the presence of still more-distant galaxies spilled across the sky. The light from those galaxies, magnified into visibility by the gravitational field of the cluster, originated more than 13 billion years ago.
To look outward into space is to peer into the past. Light travels at a constant 186,000 miles per second, or close to 6 trillion miles per year, through the vacuum of space. To observe a star 10 light-years away is to see it as it existed 10 years ago, when the light left its surface. The farther away a star or galaxy lies, the older it is, making every telescope a kind of time machine.
Astronomers theorize that the most distant, early stars may be unlike the stars we see today. The first stars were composed of pure hydrogen and helium left over from the Big Bang, and they could grow far more massive than the sun — then collapse quickly and violently into supermassive black holes of the kind that now populate the centers of most galaxies.
The new pictures were rolled out during an hourlong ceremony at the Goddard Space Flight Center that was hosted by Michelle Thaller, the center’s assistant director for science communication, with video stops around the world. A few miles away at the Space Telescope Science Institute in Baltimore, an overflow crowd of astronomers whooped and hollered, oohed and aahed, as new images flashed on the screen — evidence that their telescope was working even better than hoped.
One infrared skyscape showed Stephan’s Quintet, five galaxies packed improbably tightly in the constellation Pegasus. Four are so closely engaged in a gravitational dance that they will eventually merge. Indeed, the image revealed a band of dust that was being heated up as two of the galaxies ripped stars from each other.
A view of the Southern Ring nebula, the remnants of an exploded star, revealed hints of complex carbon molecules known as polycyclic aromatic hydrocarbons, or PAHs, floating in its midst. Such molecules drift through space, settling in clouds that then give birth to new stars, planets, asteroids — and whatever life might subsequently sprout.
“Possibly, the formation of PAHs in these stars is a very important part of how life got started,” said Bruce Balick, an emeritus professor of astronomy at the University of Washington. “I’m gobsmacked.”
The most striking image was of the Carina nebula, a vast, swirling cloud of dust that is both a star nursery and home to some of the most luminous and explosive stars in the Milky Way. Seen in infrared, the nebula resembled a looming, eroded coastal cliff dotted with hundreds of stars that astronomers had never seen before.
“It took me a while to figure out what to call out in this image,” said Amber Straughn, deputy project scientist for the telescope, as she pointed to a craggy structure.
Straughn added that she could not help thinking about the scale of the nebula, full of stars with planets of their own.
“We humans really are connected to the universe,” she said. “We’re made out of the same stuff in this landscape.”
From astronomers and at watch parties around the world, there was uniform relief and praise.
“This event blew me away,” said Alan Dressler, an astronomer at the Carnegie Observatory who was instrumental in planning for the telescope 30 years ago. “Guess I’m not as jaded as I thought.”
He added, “The growth in our understanding of the universe will be as great as it was with the Hubble, and that is really saying something. We’re in for a great adventure.”
A ‘Feeding Frenzy’ in the Sky
The pictures and other data released Tuesday were selected by a small team of imaging experts and public outreach specialists for the images’ ability to show off the new telescope’s range and power — and to knock the public’s socks off.
These will be followed in the next six months by the results of studies in NASA’s Early Release Science Programs. Some results, including images of galaxies even more distant than the one shown by Biden on Monday, will be available later this week. On Thursday, all the data gathered during the testing of the telescope and its instruments will become available.
Now that the images are out, “there will be an astronomer feeding frenzy!” Garth Illingworth, a researcher at the University of California, Santa Cruz, and an initiator of the telescope program four decades ago, wrote in an email.
The Early Release Science Programs, intended to jump-start the Webb era, include studies of the solar system, galaxies, intergalactic space, massive black holes and the evolution of stars.
Jupiter and its myriad intriguing satellites, such as Europa, the target of an upcoming NASA mission, will be one focus. Two other studies will be devoted to exoplanets, including the Trappist-1 system, just 40 light-years away, where seven planets circle a dim red-dwarf star. Three of those planets are Earth-size rocks orbiting in the habitable zone, where water could exist on the surface.
Dreaming of the Light Unseen
Just as the Hubble Space Telescope defined astronomy for the past three decades, NASA expects Webb to define the field for a new generation of researchers who have been eagerly awaiting their own rendezvous with the cosmos.
It’s been a long time coming. What began as the Next Generation Space Telescope evolved into an infrared telescope capable of sensing the heat from the earliest stars and galaxies in the universe.
Because the cosmos is expanding, those earliest stars and galaxies are rushing away from Earth so fast that their light is shifted to longer, redder wavelengths, much as the sound from an ambulance’s siren shifts to a lower register as it speeds by. The light from the most distant and earliest galaxies and stars, once blue, is now infrared “heat” radiation, invisible to the eye. So too is the radiation from carbon, ozone and other molecules that are of keen interest to astrobiologists.
An early planning committee concluded that the telescope would need to be at least 4 meters in diameter (Hubble’s was just 2.4 meters across) and highly sensitive to infrared radiation, and it would cost $1 billion. NASA’s administrator, Dan Goldin, liked the idea but worried that a 4-meter telescope would be too small to see the first stars, so he increased the size to 8 meters.
Doubled in size, however, the telescope would no longer fit aboard any existing rocket. That meant the telescope’s mirror would have to be foldable, and it would have to unfurl itself in space. NASA eventually settled on a mirror 6.5 meters wide, with seven times the light-gathering power of Hubble’s.
Moreover, the telescope would have to be cooled to minus 380 degrees Fahrenheit to prevent the telescope’s own heat from swamping the faint emanations from distant stars. (One instrument had to be even colder, minus 447 degrees Fahrenheit, just a few degrees above absolute zero.) This was accomplished by parking the telescope permanently behind a sunshade.
But all the challenges of developing and building the instrument remained. In 1990, NASA had sent Hubble into orbit with a misshapen mirror; still stinging from that embarrassment, the agency devised a long and expensive testing program for the new telescope. The price tag rose to $8 billion, and in 2011, Congress nearly canceled the project.
“Webb became the perfect storm,” Dressler recalled. “The more expensive it got, the more critical it was that it not fail, and that made it even more expensive.”
During one early test, the sun shield was torn. “When you work with a $10 billion telescope, there are no small problems,” said Thomas Zurbuchen, NASA’s associate administrator for science missions. “It’s hard to know what’s boldface and what is not.”
Christmas for Astronomers
The Webb telescope represents the combined effort of about 20,000 engineers, astronomers, technicians and bureaucrats, according to Bill Ochs, who has been the telescope’s project manager since 2011. It is now orbiting the sun at a spot called L2, where the combined gravitational fields of the sun and Earth create a stable resting spot. Its mirror, made of 18 gold-coated beryllium hexagons, suggests a sunflower floating on the blade of a giant shovel — the sunscreen that keeps the telescope cold and pointing ever outward from our star.
All of Webb’s troubles vanished on Christmas morning, when a flawless launch from French Guiana lifted the telescope past hundreds of “single points of failure” and left it with twice as much maneuvering fuel as expected and the possibility of a 20-year career in science. The mirror also proved to be twice as good as expected at detecting the shortest wavelengths of light, increasing the telescope’s resolving power.
As the Goddard ceremony wrapped up Tuesday, Zurbuchen and Mather took the stage to congratulate and praise the team that had worked together so long and well. Mather said that he had never worried that the telescope wouldn’t succeed. “Although maybe I should have,” he added.
Zurbuchen shot back: “I get paid to worry.”