The James Webb Space Telescope was designed to tunnel deeper into space and farther back in time than any previous observatory, with the audacious goal of seeing the very first galaxies that lit up the young universe. Creating pretty pictures was always a pleasant but ancillary feature of having this amazing new piece of hardware out in space.
Today, 365 days after NASA unveiled the mission’s first batch of data and images, it’s clear that the JWST can produce the hard science and the beauty shots with equal aplomb. NASA is marking the first anniversary of the JWST’s scientific debut with the release of a new image, demonstrating the telescope’s ability to re-envision the universe. The dramatic, somewhat hallucinatory image captures the dynamism of the Rho Ophiuchi cloud complex, the closest star-forming region to Earth, where planetary systems like our own could be in the initial stages of forming.
“The telescope is working better than we could have possibly hoped for,” said NASA astrophysicist Jane Rigby, who earlier this month became the senior project scientist for the JWST.
The scientific community was a little conservative in planning their agenda for the first year of observations, but this next year of science will take full advantage of what the telescope can do, Rigby said. “We’re getting bolder in year two.”
The JWST’s journey around the sun has not been without speed bumps. The first year of scientific operations included a brief pause in data collection for safety reasons and a heart-stopping collision with space dust that forced project managers to fly the observatory more or less backward from now on.
But the scientists working with the telescope’s downloaded data are thrilled by its performance as it peers into the infrared portion of the spectrum, gathering light that can’t be collected by its predecessor, the Hubble Space Telescope.
The big headline so far is that the JWST has seen lots of surprisingly bright galaxies in the early universe. This proved to be a bit befuddling.
No, the JWST did not disprove the big bang theory. Cosmology has not gone the way of phrenology. But the observations of so much light coming from the early period of galaxy formation led to a lot of head-scratching. Observation and theory have not been perfectly aligned.
“I think there is a tension,” said physicist Massimo Stiavelli, the JWST mission head at the Space Telescope Science Institute in Baltimore. “This is undeniable, because things are different from what we thought they would be.”
Major discoveries from the JWST
The JWST was conceived in the late 1980s as the successor to the yet-to-launch Hubble, but suffered many years of delays and near-death encounters with budget-minded lawmakers. It’s a $10 billion investment. It is not designed with the kind of modular features that would enable replacement parts if something went screwy.
Also it’s way out in deep space, in a gravitationally stable orbit around the sun called L2 that keeps it roughly a million miles from Earth. NASA doesn’t currently have spaceships to carry astronauts to L2 and back.
All this reinforces the joy among scientists that the telescope works as planned.
For a telescope of this design, a year is a big deal. The telescope’s mirrors have to remain extremely cold and can’t be pointed anywhere near the sun, so don’t expect to see any pretty JWST images of Venus. But a full orbit gives the telescope a chance to cover most of the universe.
JWST, which launched on Christmas morning 2021, has actually made 1½ orbits, but the first six months were devoted to deploying its huge array of gold-coated hexagonal mirrors and a sprawling sun shade to keep them cool, as well as fine-tuning its instruments.
The light gathered by those mirrors carries information about multiple layers of the universe, from the farthest, dimmest, barely perceptible galaxies to more flamboyant galaxies in the foreground and star-forming clouds of dust and gas within our own Milky Way. And it’s looked at our immediate neighborhood, the solar system, returning poster-worthy pictures of Jupiter and Saturn that are jammed with scientific data.
The early universe is where the JWST has done its most interesting and, at times, puzzling investigations. The goal is to understand how the early universe evolved, how galaxies formed and how we got to where we are — on a planet orbiting a star on one of the spiral arms of a large galaxy.
“Our home is the Milky Way,” said Brant Robertson, a theoretical astrophysicist at the University of California at Santa Cruz. “That is a galaxy. It’s a beautiful galaxy. We can take pictures from the inside. But it begs the question: How did it get here? How did it form?”
This cosmic archaeology is why the JWST was built in the first place. One strange feature of the universe is that light is eternal. It gets fainter but it’s still there, including the most ancient light, heavily shifted into the infrared portion of the spectrum by the expansion of space that’s been happening since the big bang. Astrophysicists can use the JWST to scan for extremely high-redshift galaxies, digging ever deeper into the past.
Robertson co-wrote one of two recent papers that describe the most distant galaxy yet detected and confirmed by the JWST, named JADES-GS-Z13-0. It was found at redshift 13.2, which corresponds to about 320 million years after the big bang. There are claims of possible galaxies at higher redshifts, but they await confirmation, he said.
Asked what the galaxy looks like, he said: “It’s a smudge.”
But what if you could somehow get in a spacecraft and transport yourself through various wormholes into the distant past and hover right next to that galaxy. Then what would it look like?
“If you could be right up next to it, the galaxy itself would be very blue to your eyes, because it’s forming stars,” Robertson said. “It would be a very blue sparkler in the early universe.”
A puzzle about early galaxies
Right away, astronomers looking at the JWST data on the early universe spotted something that defied expectations: a lot of oddly bright galaxies.
Brightness is an approximation for mass. Very bright galaxies, therefore, would normally be assumed to be very massive. But galaxies need time to grow. The theorists had previously worked out a general timeline for the evolution of early galaxies, and the ones detected by the JWST look at first glance remarkably mature for their age.
The JWST may be telling scientists that galaxy formation in the early universe was somehow more efficient than previously known.
“There’s some tweaking we need to do in our theories for how those very early galaxies formed and grew their stars,” said Jeyhan Kartaltepe, an astrophysicist at the Rochester Institute of Technology.
“Nothing we’ve seen makes me think we’ve broken cosmology,” Rigby said. “What it is telling us is that galaxies got their act together earlier than we gave them credit for.”
Counterintuitively for those of us who are not astrophysicists, black holes could be another factor in the luminosity of those early galaxies. Although by definition a black hole is a structure with such an intense gravity field that even light cannot escape, the region around a black hole can glow as gas and dust become superheated falling toward the event horizon.
Last year Rebecca Larson, at that time still a doctoral candidate at the University of Texas at Austin, saw something peculiar as she scrutinized data from an extremely distant galaxy named CEERS 1019. It emitted that light more than 13 billion years ago — back when the universe was just getting rolling, and galaxies were small, ill-formed gaggles of hot, young, bright-blue stars.
Larson was puzzled by the unusually bright light coming from the core of CEERS 1019. “What the heck is this?” she thought.
What she guessed it to be — correctly — is a supermassive black hole. The galaxy, though young, had already managed to grow a black hole that scientists estimate to have a mass equal to 10 million suns. A report from Larson and her colleagues describe this as the earliest active supermassive black hole ever detected.
Excitement over exoplanets
What the past year has also started to show is that the JWST is, in the words of astrophysicist Garth Illingworth, a “spectroscopic powerhouse.” It has proved to be spectacular at picking through the spectra of the light it gathers, which carries information about the object being observed.
That ability yielded one of the telescope’s first major discoveries: carbon dioxide in the atmosphere of a giant planet, WASP 39b, orbiting a distant star. The planet itself isn’t visible with current technology. But as it passes in front of, or behind, its parent star, the changes in starlight encode information about the atmosphere of the planet.
Until the JWST, no one had made a definitive detection of carbon dioxide in an exoplanet’s atmosphere, said Knicole Colon, a NASA astrophysicist.
“The first time we saw the spectral signature of that feature, it was just beautiful,” she said. “It hit us in the face. Here’s this whopping signal, which was fantastic.”
To be clear, scientists looking at spectra are looking at graphical presentations of data, not actual images. Larson, who found the supermassive black hole, was so transfixed by the spectral signature of a central bright region in that galaxy that, as she put it, “I never thought to go look at the actual images from JWST.”
That’s when Kartaltepe showed her the image of the galaxy obtained by the telescope. Strikingly, the galaxy had three bright spots, with a particularly bright spot right in the middle. That was Larson’s supermassive black hole.
“I just started crying,” she said.