Free Astronomy Magazine March-April 2026

MARCH-APRIL 2026 T his graphic illustrates the pronounced narrow peak of the spectra that caught researchers’ attention in a small sample of galaxies, represented here by the galaxy CEERS 4233-42232. It is the combination of a narrower-than-expected spectra, along with a tiny, point-like appearance, that makes these galaxies stand out. Typically, distant point-like light sources are quasars, but quasar spectra have a much broader shape. [NASA, ESA, CSA, Joseph Olmsted (STScI)] the universe’s age of 13.8 billion years). Spectral data gives astrono- mers more information than they can get from an image alone, and for these nine sources it doesn’t fit existing definitions. They are too far away to be stars in our own galaxy, and too faint to be quasars, which are so brilliant that they outshine their host galaxies. Though the spectra resemble the less distant “green pea” galaxies discovered in 2009, the galaxies in this sample are much more compact. “Like spectra, the detailed genetic code of a platy- pus provides additional information that shows just how unusual the an- imal is, sharing genetic features with birds, reptiles, and mammals,” said Yan. “Together, Webb’s imag- ing and spectra are telling us that these galaxies have an unexpected combination of features.” Yan ex- plained that for typical quasars, the peaks in their characteristic spectral emission lines look like hills, with a broad base, indicating the high ve- locity of gas swirling around their supermassive black hole. Instead, the peaks for the “platypus popula- tion” are narrow and sharp, indicat- ing slower gas movement. While there are narrow-line galaxies that host active supermassive black holes, they do not have the point- like feature of the sample Yan’s team has identified. Has Yan’s team discovered a missing link in the cos- mos? Once the team determined that the objects didn’t fit the defini- tion of a quasar, graduate student researcher Bangzheng Sun analyzed the data to see if there were signa- tures of star-forming galaxies. “From the low-resolution spectra we have, we can’t rule out the pos- sibility that these nine objects are star-forming galaxies. That data fits,” said Sun. “The strange thing in that case is that the galaxies are so tiny and compact, even though Webb has the resolving power to show us a lot of detail at this dis- tance.” One proposal the team sug- gests is that Webb, as promised, is revealing earlier stages of galaxy formation and evolution than we have ever been able to see before. It is generally accepted across the astronomy community that large, massive galaxies like our own Milky Way grew by many smaller galaxies merging together. But, Yan asks, what comes before small galaxies? “I think this new research is present- ing us with the question, how does the process of galaxy formation first begin? Can such small, building- block galaxies be formed in a quiet way, before chaotic mergers begin, as their point-like appearance sug- gests?” Yan said. To begin answer- ing that question, as well as to determine more about the nature of their odd platypuses, the team says they need a much larger sample than nine to analyze, and with higher-resolution spectra. “We cast a wide net, and we found a few examples of something in- credible. These nine objects weren’t the focus; they were just in the back- ground of broad Webb surveys,” said Yan. “Now it’s time to think about the implications of that, and how we can use Webb’s capabilities to learn more.” !