If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



What the first James Webb Space Telescope images could mean for chemistry

New photos demonstrate the infrared telescope’s potential for unveiling the chemical complexity of our universe

by Ariana Remmel
July 14, 2022 | A version of this story appeared in Volume 100, Issue 25


Thousands of small galaxies appear across this view. Their colors vary. Some are shades of orange, while
others are white. Most appear as fuzzy ovals, but a few have distinct spiral arms. In front of the galaxies
are several foreground stars. Most appear blue, and the bright stars have diffraction spikes, forming an
eight-pointed star shape. There are also many thin, long, orange arcs that curve around the center of
the image.
The James Webb Space Telescope's first deep field image, taken with its Near-Infrared Camera, shows distant galaxies as they appeared billions of years ago.

Astronomers have now seen just how powerful the long-awaited James Webb Space Telescope (JWST) could be for revealing the chemical complexity of our universe. NASA and its partners—the European Space Agency, the Canadian Space Agency, and the Space Telescope Science Institute—released five images on July 12 that show scenes across the universe, including the birth of stars, black holes, and tightly clustered galaxies. The data came from a suite of onboard instruments designed to capture infrared wavelengths of light from the earliest moments of the universe.

The JWST has already outperformed the expectations of its engineers by snapping an image of the whirling galaxies of the cluster SMACS 0723 as it appeared 4.6 billion years ago. The gravity and dark matter from this galaxy cluster help to magnify and distort even more ancient galaxies that formed less than a billion years after the Big Bang. “And we’re seeing the elements of oxygen and hydrogen, as well as neon,” Jane Rigby, a JWST project scientist with NASA Goddard Space Flight Center, said during a press conference at which the images were unveiled. “This is how the oxygen in our bodies was made in stars in galaxies, and we’re seeing that process get started.”

Infographic titled “Distant Galaxy in SMACS 0723, Webb Spectrum Showcases a Galaxy’s Composition;
NIRCam Imaging and NIRSpec Microshutter Array Spectroscopy.” At the top is a thin horizontal
reference image of the galaxy cluster, labeled NIRCam Imaging. A zoom-in in view of one galaxy in the
field is pulled out. The pull-out image shows a red pixelated blob. The image is labeled 13.1 billion years
to indicate the age of the light shown. Below this is a spectrum of the galaxy, labeled NIRSpec
Microshutter Array Spectroscopy. It is plotted as a line graph of brightness versus wavelength. The
overall shape of the line is flat with many prominent spike-like peaks. Ten peaks are labeled with the
element that is emitting that wavelength of light. From left to right (shorter to longer wavelength) the
peaks are: oxygen, neon, hydrogen, neon, hydrogen, hydrogen, oxygen, hydrogen, oxygen.
The Near-Infrared Spectrograph on the James Webb Space Telescope identified the chemical composition (bottom) of a galaxy that emitted light 13.1 billion years ago (top). The galaxy is among the thousands seen within the telescope's first deep field image.

Knicole Colón, a JWST exoplanet project scientist with NASA Goddard, also shared data showing the chemical fingerprint of water vapor in the atmosphere of a hot, gaseous exoplanet about half the mass of Jupiter called WASP-96 b. The data suggest that this vapor forms steamy clouds and haze, which had not been observable with the ground-based telescopes that initially identified water on this exoplanet. Though astrobiologists don’t expect WASP-96 b to host life, the techniques used to analyze its atmosphere are crucial for finding potentially habitable exoplanets with liquid water.

The analysis of WASP-96 b’s water was among the most exciting revelations for Brett McGuire, an astrochemist at the Massachusetts Institute of Technology. The telescope is “probing the chemical composition of the atmosphere of another planet in another solar system,” he said. JWST will give scientists on Earth an unprecedented view into the atmospheric chemistry of other worlds. “It’s just going to be incredible.”

McGuire is especially excited to see results from the telescope’s Mid-Infrared Instrument (MIRI) that will detect the spectroscopic signatures of atoms and molecules across large swaths of space. With this instrument, scientists performed a spectral analysis of a supermassive black hole within a group of five galaxies called Stephan’s Quintet. MIRI detected differences in the chemical composition of different regions around the black hole, showing that it is surrounded by a cloud of fine silicate that is distinct from the ionized gases flowing away from it. In the coming year, MIRI will be used to study the chemical complexity of interstellar ice clouds where many carbon-based molecules are synthesized.

On the left side are two reference images of a group of galaxies. On the right are two emission spectra:
jagged line graphs of brightness of light versus wavelength of light. The peaks on the graphs are labeled
with the names of various elements and compounds. The top graph shows the spectrum of light emitted
from the edge of the core of the galaxy, with 10 peaks labeled: iron, argon, neon, sulfur, neon, neon,
neon, sulfur, neon, and oxygen. The bottom graph shows the spectrum of light emitted from the core of
the galaxy, with 3 peaks labeled for molecular hydrogen and one broad valley labeled for silicates.
The James Webb Space Telescope's Mid-Infrared Instrument analyzed regions surrounding a supermassive black hole within a galaxy in Stephan's Quintet (left). The instrument found distinct chemical signatures for ionized gases flowing away from the black hole (top right) compared to the dust clouds immediately around it (bottom right).

This photo release marks the grand opening of JWST to science, NASA officials said. Data from these experiments will be collected in a publicly accessible archive that will spur new insights into our universe for decades to come. “The amazing thing about Webb is the speed at which we can churn out discoveries,” Rigby says. “We’re going to be doing discoveries like this every week.”


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.