Are These 'Little Red Dots' The Universe's First Stars And Not Galaxies?
JWST spotted over 300 mysterious red dots from the early universe. Though once thought to be galaxies, scientists now believe they may be massive stars, not galaxies
The James Webb Space Telescope (JWST) has realised humanity's ambition of observing the early universe. It recently transmitted images from when the universe was merely 600 million years old. However, these images revealed something puzzling: hundreds of small red spheres, now referred to as Little Red Dots (LRDs).
JWST identified over 300 of these red dots. Despite being faint and extremely distant, they appear unusually bright, suggesting a very high mass. Initially, scientists believed these were early galaxies, but new research proposes a surprising alternative: they may actually be supermassive stars (SMS), not galaxies.
A recent study by Devesh Nandal of the University of Virginia and Abraham Loeb of Harvard suggests these mysterious LRDs could be Population III supermassive stars; stars that formed in the very early universe. These stars contained no metals and could have masses up to 1 million times that of our Sun. However, they lived for only a few thousand years before exploding as supernovae.
These explosions may have contributed to the formation of the first supermassive black holes (SMBHs), which are now found at the centres of quasars and large galaxies.
The red appearance of LRDs is due to the thick clouds of gas and dust surrounding them. Initially, scientists speculated they might be active galactic nuclei (AGN), with black holes at their centres. However, key differences such as the absence of X-ray emissions, a flat infrared spectrum, and minimal light variation challenged that theory, prompting researchers to consider alternative explanations.
What Did the Research Find?
Nandal and Loeb created a model of a metal-free supermassive star with a mass of one million Suns. They found that its light spectrum and brightness closely matched those of the LRDs observed by JWST.
Most importantly, the model showed a strong Hβ emission line and Balmer absorption lines, features typically created when gas expands on the surface of a supermassive star. This strongly supports the theory that LRDs are not galaxies but giant stars.
Could This Solve a Cosmic Mystery?
If proven true, this theory could help solve a long-standing puzzle: how did SMBHs form so soon after the Big Bang? According to current models, they should have taken billions of years to develop. However, the presence of quasars and SMBHs just a few hundred million years after the Big Bang contradicts this.
The theory of short-lived, massive stars collapsing into black holes provides a much simpler explanation. The researchers adhered to the principle of Occam's Razor, the idea that the simplest explanation is often the most likely. While the AGN theory requires multiple complex assumptions, the SMS model explains all the observed features straightforwardly.
Nevertheless, scientists emphasise that this is still a developing theory. Further telescopic observations and improved modelling will be necessary to confirm whether these Little Red Dots are indeed ancient supermassive stars. Despite the limitations of current technology, JWST has opened a new window into the universe's earliest moments – and potentially, into one of its greatest mysteries.
First Published:
Disclaimer: Comments reflect users' views, not News18's. Please keep discussions respectful and constructive. Abusive, defamatory, or illegal comments will be removed. News18 may disable any comment at its discretion. By posting, you agree to our Terms of Use and Privacy Policy.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
NDTV
4 hours ago
- NDTV
Is There Life Present On K2-18b Exoplanet? New Observations Provide Insights
A team of scientists claimed in April that a planet orbiting a distant star bore a possible signature of life, but the latest observations suggest otherwise. At the University of Cambridge, Nikku Madhusudhan and his colleagues claimed in April that they found hints of the molecules dimethyl sulphide (DMS) and dimethyl disulphide (DMDS) in the atmosphere on K2-18b using the James Webb Space Telescope (JWST) data. On Earth, these sulfur-based compounds are primarily produced by marine microorganisms. Madhusudhan said those were the "first hints we are seeing of an alien world that is possibly inhabited". K2-18b is a super-Earth located 124 light-years away in the constellation Leo. It is approximately 2.6 times the diameter and 8.6 times the mass of Earth, orbiting a cool red dwarf star within the habitable zone. What did the other researchers say? Other researchers also analysed the same data using different statistical models and didn't find evidence for the presence of these molecules. Renyu Hu at the California Institute of Technology and his colleagues teamed up with Madhusudhan and his group to analyse the observations of K2-18b. "The paper does not provide conclusive evidence for the existence of this molecule in the atmosphere," Hu said as quoted by the New Scientist. The second team found no statistical evidence.. However, Madhusudhan told New Scientist that his colleagues analysed the data again, which made him "more confident" that DMS was the best explanation. James Webb's near-infrared camera was used by the second group of researchers to look at the light coming from K2-18b's star. It can reveal what molecules exist in the atmosphere after passing through the planet's atmosphere. The camera looked at a different wavelength of light compared to the mid-infrared measurements that were used for the analysis done in April. "This model dependency just speaks to the fact that it is a very weak signal, if there is any signal at all," Hu said. "I would just exercise caution". "This paper is very clear in saying that there is no evidence for dimethyl sulphide. There is no statistical evidence for any of these gases," Luis Welbanks at Arizona State University said as quoted. "We seem to be coming to the end of the debate on whether DMS is present in detectable levels in the [K2-18b] atmosphere, as the increased precision has not helped to detect it at a higher significance," Jake Taylor at the University of Oxford said, as quoted. Scientists previously proposed that K2-18b could be a "Hycean world," a planet with a hydrogen-rich atmosphere and vast ocean, making it a prime candidate for hosting life. Hu and his team found that for certain hydrogen-rich atmospheres, chemicals can produce DMS without the presence of life. "A key takeaway is that biosignatures are going to be hard, no matter what kind of planet we are talking about," Jacob Bean, an astronomer at the University of Chicago, who was not involved in the study, said as quoted by The New York Times. All researchers, however, agreed that the planet is rich in water. Strong evidence for the presence of methane and carbon dioxide was also found by Hu and his team. It implies the existence of water, Hu said. However, additional studies could provide insights into the planet's atmospheric composition, temperature profile and potential biosignatures.
India Today
13 hours ago
- India Today
Astronomers witness birth of a new solar system for the first time
In a remarkable achievement, international astronomers have, for the first time, observed the very moment planets begin to form around a distant star, offering a direct window into the earliest stages of a solar system's historic discovery, combining the power of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and the James Webb Space Telescope (JWST), represents a leap forward in our understanding of how worlds like our own come to star in question, known as HOPS-315, sits 1,300 light-years away from Earth. It is a 'proto' star, newly formed and swaddled in a dense disk of gas and dust, the very building blocks from which planets emerge. Using JWST's infrared sensitivity, researchers first identified chemical fingerprints of hot, crystalline minerals, notably silicon monoxide (SiO), beginning to solidify within this disc. Follow-up observations with ALMA pinpointed these minerals' location, revealing they were forming close to where our asteroid belt orbits in the Solar System today. These images illustrate how hot gas condenses into solid minerals around the baby star HOPS-315. (Photo: ESO) 'This is the earliest moment of planet formation ever observed outside our Solar System,' said study lead author Professor Melissa McClure of Leiden University, whose results were published today in Professor Merel van 't Hoff of Purdue University likened the findings to 'a picture of the baby Solar System,' adding that HOPS-315 closely resembles what our Sun and planets would have looked like 4.6 billion years now, astronomers have detected fully formed, massive, newborn planets or observed younger protoplanetary discs, but never witnessed the precise moment when small, rocky solids, the first 'seeds' of planets, began to condense and discovery of solidifying SiO minerals, trapped both in gas and crystal form, confirms that planetesimal formation is underway around HOPS-315.'This process has never been seen before anywhere outside our Solar System,' said co-author Professor Edwin Bergin of the University of Michigan. The location of the mineral signals, equivalent to our asteroid belt, further strengthens the connection to our own origins, echoing the materials found in ancient meteorites and asteroids that predate Elizabeth Humphreys, who wasn't involved in the study, called the findings 'a very early stage of planet formation,' and emphasised the unique synergy between JWST and ALMA in revealing such cosmic are excited that with HOPS-315, they now have an unprecedented laboratory for studying the processes that shaped not just our Solar System, but potentially countless worlds across the galaxy.- EndsTrending Reel
NDTV
a day ago
- NDTV
Exoplanet 35 Light-Years Away Offers Hope for Life Beyond Earth
A team of scientists has studied the L 98-59 planetary system and confirmed the existence of a fifth planet, named L 98-59 f, in the star's habitable zone. The zone has conditions that could allow liquid water to exist. L 98-59 is a small red dwarf located just 35 light-years from Earth. In 2019, NASA's TESS space telescope found that it hosts three small transiting exoplanets. A fourth planet was revealed through radial velocity measurements with the European Southern Observatory's ESPRESSO spectrograph. Now, the team led by the Trottier Institute for Research on Exoplanets (IREx) at the Universite de Montreal has found a fifth one in the system. "These new results paint the most complete picture we've ever had of the fascinating L 98-59 system," said Cadieux in the press release. "It's a powerful demonstration of what we can achieve by combining data from space telescopes and high-precision instruments on Earth, and it gives us key targets for future atmospheric studies with the James Webb Space Telescope [JWST]." The exoplanet has a minimum mass 2.8 times that of Earth and has been categorised as a super-Earth. L 98-59 f follows an almost perfectly circular orbit around its star, receiving roughly the same amount of stellar energy as Earth. Its location in the habitable zone suggests that liquid water could exist on its surface under suitable atmospheric conditions, making it a potential candidate to support life. If L 98-59 f has an atmosphere, telescopes like the James Webb Space Telescope (JWST) may be able to detect water vapour, carbon dioxide or even biosignatures. Cadieux said that the discovery highlights the "diversity of exoplanetary systems" and also "strengthens the case for studying potentially habitable worlds around low-mass stars". "With its diversity of rocky worlds and range of planetary compositions, L 98-59 offers a unique laboratory to address some of the field's most pressing questions: What are super-Earths and sub-Neptunes made of? Do planets form differently around small stars? Can rocky planets around red dwarfs retain atmospheres over time?" René Doyon, co-author of the study, who is a professor at UdeM and the Director of IREx, said. The findings are reported in research that will appear in The Astronomical Journal titled "Detailed Architecture of the L 98-59 System and Confirmation of a Fifth Planet in the Habitable Zone."
