Benedictine Astronomer Explains Significance of New Space Telescope Images

Thursday, July 14, 2022

Dr. Christopher Shingledecker, assistant professor of Physics and Astronomy at Benedictine College, has been working with land-based telescopes for several years and is scheduled to be among the first scientists to do research using NASA’s new James Webb Space Telescope (JWST). He has taken the time to explain the significance of the first images to be transmitted from that telescope.

“The five spectacular images that have just been released are, in a sense, proof that each instrument is functioning as intended,” said Shingledecker. “But even more than providing a technical check, they tell a story about the universe and reveal new, never-before-seen details that promise many more to come.”

He explained that the first image released by the JWST team is of the galaxy cluster SMACS 0723. It is what astronomers call a “deep field” image, looking very carefully at a very small patch of the sky. In that seemingly empty speck of blackness, JWST, like the Hubble Space Telescope (HST) before it, revealed a myriad of galaxies, each of which contains billions of stars and planets.

“If you look carefully, you’ll notice that some of the galaxies seem stretched into thin arcs of light,” said Shingledecker. “This is because the massive gravity of the galaxy cluster is strong enough to bend space and by extension, the light from far distant galaxies behind the cluster that may have formed a mere billion years after the big bang.”

He said the cameras used to record this image, NIRcam and MIRI, look at colors that humans can’t see, so astronomers have assigned colors invisible in the infrared spectrum with colors from the visible light spectrum: light from stars is given as blue , space dust in these galaxies in shown as red, and yellow/green shows the kinds of carbon-bearing molecules that are ubiquitous in space, but which have only recently begun to be specifically identified by Shingledecker and his research collaborators.

Figure 1: SMACS 0723 (Credits: NASA, ESA, CSA, and STScI)


Shingledecker said the next image in the group is of a smaller cluster of galaxies, known as Stephan’s Quintet, or Hickson Compact Group 92 (HCG 92). This galaxy cluster, which you may recognize from the opening scenes of It’s a Wonderful Life, shows an important finding in 20th century astronomy, namely, that galaxies like our Milky Way tend to form in groups that interact with each other. These galaxies dance around each other over cosmic aeons, sometimes even colliding and merging. If one of the galaxies harbors a supermassive black hole, as does the Milky Way and the topmost galaxy in the image here, NGC 7319, it can rip away material from its neighbors.

Figure 2: Stephan's Quintet  (Credits: NASA, ESA, CSA, and STScI)


Moving from clusters of galaxies to our own Milky Way, Shingledecker said the next image shows a “stellar nursery” in the Carina Nebula. Using the MIRI instrument, JWST has already revealed previously invisible regions where stars and planets are forming in embryos of galactic dust and gas. Light from the fully developed stars at the top of the image is in the process of carving the dramatic peaks of gas and dust shown in red where their younger stellar siblings are developing, the tallest of which is roughly 7 light years tall. “Of all five of the spectacular images from JWST, this is my favorite, not only because of its ethereal beauty, but also because it depicts the kinds of interstellar regions that are the focus of my own research,” Shingledecker said. “As a molecular astrophysicist, I try to better understand what such nebulae are made of, and what role things like the intense starlight of neighboring stars, or the invisible but ubiquitous cosmic radiation play in that process.”

Figure 3: The Carina Nebula (Credits: NASA, ESA, CSA, and STSCI)


Shingledecker said astronomers have recently realized that, as most stars develop in their embryonic cocoons of gas and dust, planets are forming alongside them.

“When you look up at the night sky, you can imagine most of the twinkling stars you see as having their own solar systems of so-called exoplanets,” he said.

Astronomers have only recently been able to detect these worlds outside our solar system, but already we know of around 5,000. Learning much about these exoplanets is challenging, but one especially difficult problem has been identifying what their atmospheres are like. Using HST, scientists have seen a few tantalizing hints that reveal a few fascinating details, but with JWST, they hope to begin learning much more. Astronomers use spectral fingerprints like the one shown in the next image to identify which molecules are in the atmosphere of exoplanets, and already the spectrum taken by the JWST represents the most detailed information to date on this topic. It shows the “fingerprints” of water molecules in the atmosphere of an exoplanet known as WASP 96b, a mere 1,150 light-years away. Though WASP 96b, like Earth, has water in its atmosphere, it is far from habitable. Nevertheless, this technique of looking at the spectra of exoplanet atmospheres is a very useful one and could even be used to detect alien life on a distant world.

Figure 4: Atmospheric spectrum of WASP 96b (CREDITS: NASA, ESA, CSA, AND STSCI)


“Moving to the last image, we see one of the final stages of a star’s life. As a star begins to use up its internal fuel supply, it begins puffing out three-dimensional smoke rings that form what astronomers call planetary nebulae – which, despite the name, are much, much smaller than the Carina Nebula in the previous image,” said Shingledecker.

This image is of a star about 2,000 light-years from Earth called NGC 3132, but more commonly referred to as the Southern Ring Nebula because it is visible from Earth’s Southern hemisphere. One of the most remarkable new discoveries of the JWST team, using the MIRI instrument, has been the halo of newly created stardust around the dying star, shown in the right-hand image. This stardust, as it flies away from its stellar forge, will eventually become incorporated into the surrounding interstellar medium, like the dust of the Carina Nebula, and will eventually go on to form other stars in a cosmic chemistry cycle.

Figure 5: The Southern Ring Nebula (CREDITS: NASA, ESA, CSA, AND STSCI)


“These images are remarkable, in part, because they give us a previously impossible glimpse of the infrared universe, a glimpse that has even now already expanded our knowledge of the cosmos,” said Shingledecker. “They are also a testament to the decades of hard work by scientists and engineers around the world. Just as the images from the Hubble Space Telescope fired the imaginations of millions and defined how we thought of the night sky, so too, I think, will those from the JWST. Using it, we have already seen the gravitationally stretched arcs of some of the most ancient galaxies but have also peered into the stellar nurseries of our own Milky Way where stars are currently in the process of forming.”

Founded in 1858, Benedictine College is a Catholic, Benedictine, residential, liberal arts college located on the bluffs above the Missouri River in Atchison, Kansas. The school is proud to have been named one of America’s Best Colleges by U.S. News & World Report, the best private college in Kansas by The Wall Street Journal, and one of the top Catholic colleges in the nation by First Things magazine and the Newman Guide. It prides itself on outstanding academics, extraordinary faith life, strong athletic programs, and an exceptional sense of community and belonging. It has a mission to educate men and women within a community of faith and scholarship.

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