NASA’s James Webb Space Telescope (JWST) has discovered some strange cosmic objects, puzzling astronomers around the world. These odd sightings have features of both stars and galaxies, which has led researchers to affectionately call them “platypuses,” after the animal known for its mix of traits. These findings could offer insights into how galaxies formed billions of years ago during the universe’s early days.
Initially, the new objects appeared as tiny points of light in the JWST’s data. However, when scientists took a closer look, they noticed more galaxy-like characteristics. “If you examine each feature alone, it’s just a jumble,” explained Haojing Yan, an astronomer at the University of Missouri. “Combining those features makes it even stranger.” This discovery sparked curiosity about what else might be hiding in the cosmos.
Soon after JWST launched in 2021, it began uncovering unusual objects of unknown origins. Inspired by these finds, Yan and two students started searching through data to spot more of these peculiar items. They sifted through around 2,000 sources and identified nine that stood out. While typically, compact objects are thought to be point sources (usually stars), these had larger and more diffuse characteristics, leading to their classification as “point-like.”
When Yan and his team analyzed the light emitted from these objects, they expected broad emission lines typical of stars. Instead, they found narrow lines that suggested ongoing star formation, a characteristic often seen in galaxies. Intrigued, the researchers turned their attention to quasars—powerful objects at the centers of galaxies that emit bright light due to supermassive black holes. Yet, even though the newfound objects resembled quasars, they were dimmer and had narrower spectral signatures than known quasars. “Our objects are not quasars,” Yan clarified.
This raises the question: what exactly are these mysterious objects? One possibility is that they may belong to a new category of active galactic nuclei known as narrow-line AGNs. Yet, even these typically appear as point sources. Yan suggested they could indeed be a brand-new class, as existing narrow-line AGNs don’t fit this new profile.
Another theory posits that these could be young star-forming galaxies. Such galaxies are known for their rapid star creation and produce narrow emission lines, similar to how platypuses possess unique features. Bangzheng Sun, also from the University of Missouri, discussed this theory at a recent news conference, noting that if these objects are indeed star-forming galaxies, they wouldn’t be more than 200 million years old. They’re still in their formative stages.
However, the slightly larger size of these galaxies is unusual. “They must be creating stars from the inside out,” Sun observed, which presents a process not typically seen. Yan noted that while most star-forming activity tends to be violent and chaotic, “our objects suggest that this star formation could happen more peacefully, keeping their compact appearance intact.” This contrasts with conventional understanding of galactic formation.
The discovery of these nine objects raises more questions than answers, but it’s clear they are exceptional. Researchers are eager to study more of these peculiar objects in future JWST observations. Yan summarized perfectly, “These nine objects are special. They are our platypuses.” As we continue to explore the universe, more surprises may be waiting, enriching our understanding of cosmic evolution and the mysteries of the universe.
