https://phys.org/news/2026-01-complex-life-planets-orbiting-galaxy.html Phys.org Topics * Week's top * Latest news * Unread news * Subscribe [ ] Science X Account [ ] [ ] Sign In Sign in with Forget Password? Not a member? Sign up Learn more * Medical Xpress Medicine * Tech Xplore Technology * * share this! * 20 * Tweet * Share * Email 1. Home 2. Astronomy & Space 3. Astrobiology 1. Home 2. Astronomy & Space 3. Planetary Sciences * * * --------------------------------------------------------------------- January 12, 2026 report Complex life on planets orbiting the galaxy's most common stars may be unlikely by Paul Arnold, Phys.org [paul] Paul Arnold contributing writer Meet our staff & contributors Learn about our editorial standards edited by Gaby Clark, reviewed by Robert Egan [Gaby] Gaby Clark scientific editor Meet our editorial team Behind our editorial process [Robert] Robert Egan associate editor Meet our editorial team Behind our editorial process Editors' notes This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: fact-checked preprint trusted source proofread The GIST Add as preferred source --------------------------------------------------------------------- M dwarf star Artist's impression of a M dwarf star surrounded by planets. Credit: NASA/JPL-Caltech/MSSS In a blow to anyone dreaming that complex life may exist elsewhere in the universe, a new study suggests we're unlikely to find it around many of the most common stars in the galaxy. Earth-like planets orbiting small, red stars known as M-dwarfs are often considered the right size and at the right distance from their sun to harbor life. However, according to researchers from San Diego State University, these worlds may not have the right kind of light to support multicellular organisms. Photosynthesis is key Here on Earth, plants and bacteria turn sunlight into energy through photosynthesis, releasing oxygen as a byproduct. During the Great Oxidation Event around 2.3 billion years ago, significant quantities of oxygen began to accumulate in our atmosphere, eventually reaching levels capable of supporting multicellular life. According to our understanding, a similar process would have to occur on other planets for complex life to start evolving. Photosynthesis requires a specific kind of light known as Photosynthetically Active Radiation (PAR). This is the specific range of sunlight (400 to 700 nanometers) that plants, algae and cyanobacteria need to thrive. Although it was known that light from M-dwarf stars like TRAPPIST-1 is mostly infrared, which falls outside this range, what was unknown was how this would slow down the evolutionary clock. Complex life on planets orbiting the galaxy's most common stars may be unlikely, according to new research The incident photon flux density for the modern-day Earth (black), Archean Earth at 2.65 Ga (blue), and TRAPPIST-1e (red). The spectral resolution has been reduced for clarity. The shaded regions represent three relevant bandpasses for photosynthesis: standard PAR (0.40-0.70 m), extended PAR (0.40-0.75 m), and anoxic PAR (0.40-1.1 m). Credit: arXiv (2026). DOI: 10.48550/arxiv.2601.02548 By comparing light from these red stars to our own sun and modeling the oxygen production of various bacteria, the team calculated that because these stars produce so little usable energy, the accumulation of oxygen would be far too slow. Potentially, on a planet like TRAPPIST-1e, it would take 63 billion years in a worst-case scenario to reach the oxygen levels seen on Earth through photosynthesis. Even when they ran more optimistic calculations that assumed alien bacteria could adapt to the light conditions or thrive in the dark, the timeline for a Cambrian Explosion (an evolutionary event marked by the appearance of a variety of complex animals) would still exceed ten billion years. "We conclude that on such a hypothetical planet [a theoretical Earth-sized world orbiting an M-dwarf star used for the study's calculations], oxygen would never reach significant levels in the atmosphere, let alone a Cambrian Explosion," commented the researchers in their paper published on the arXiv preprint server. "Thus complex animal life on such planets is very unlikely." There could still be something out there Because most of the stars in our galaxy are M-dwarfs, this study suggests that the conditions required for complex biology may be rarer than previously thought. But of course, the dream of finding life elsewhere is not over. While the math suggests these red dwarf systems may be limited to simple microbial life, complex organisms could still exist on other types of worlds. This research could help scientists focus their search on systems around the suns that produce high-energy light needed to spark an evolutionary explosion. Written for you by our author Paul Arnold, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan--this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you. More information: Joseph J. Soliz et al, Dearth of Photosynthetically Active Radiation Suggests No Complex Life on Late M-Star Exoplanets, arXiv (2026). DOI: 10.48550/arxiv.2601.02548 Journal information: arXiv (c) 2026 Science X Network Citation: Complex life on planets orbiting the galaxy's most common stars may be unlikely (2026, January 12) retrieved 12 January 2026 from https://phys.org/news/ 2026-01-complex-life-planets-orbiting-galaxy.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. --------------------------------------------------------------------- Explore further Life can thrive around even the smallest stars, study claims --------------------------------------------------------------------- 20 shares * Facebook * Twitter * Email Feedback to editors * Featured * Last Comments * Popular Complex life on planets orbiting the galaxy's most common stars may be unlikely 3 hours ago 1 Aerosol pollution found to thicken fog over Northern India--especially at night 5 hours ago 0 Asteroseismology study probes properties of newly discovered pulsating white dwarf 6 hours ago 0 Sinking boreal trees in the deep Arctic Ocean could remove billions of tons of carbon each year 7 hours ago 3 Atom-thin, content-addressable memory enables edge AI applications 8 hours ago 0 --------------------------------------------------------------------- [gif] El Nino and La Nina synchronize global droughts and floods, study finds 51 minutes ago [gif] What most corporate carbon reports get wrong, and how to fix them 55 minutes ago [gif] Atmospheric physicists find error in widely cited Arctic snow cover observations 1 hour ago [gif] Fruit flies' embryonic stage reveals that climate adaptation begins early 1 hour ago [gif] Robotic nanoprobe enables precise extraction of a single mitochondrion from a living cell 1 hour ago [gif] Designer enzyme enables yeast to produce custom fatty acids, reducing need for palm oil 1 hour ago [gif] Fungal mechanism reveals how powdery mildew overcomes wheat immune defenses 1 hour ago [gif] How E. coli exploit fluid flow and channel shape to swim upstream and cause infections 1 hour ago [gif] Open-source model more accurately measures greenhouse gas emissions from natural gas 1 hour ago [gif] An AI-driven strategy to accelerate microbial gene function discovery 2 hours ago --------------------------------------------------------------------- Relevant PhysicsForums posts Unexpected findings in need of an explanation (retrograde motion of Mars) 1 hour ago How can a multiple conjunction occur during a retrograde motion? 7 hours ago What keeps dark matter in galactic halos? 23 hours ago Rotation curve in spiral galaxy velocity and uniform velocity dispersion Jan 11, 2026 Our Beautiful Universe - Photos and Videos Jan 9, 2026 Contradictions in the Distribution of Gamma-Ray Bursts Jan 7, 2026 More from Astronomy and Astrophysics --------------------------------------------------------------------- * Related Stories [gif] Life can thrive around even the smallest stars, study claims Sep 26, 2022 [gif] Earth-like biospheres on other planets may be rare Jun 23, 2021 [gif] Atmospheres in the TRAPPIST-1 system should be long gone Feb 5, 2024 [gif] Could life at TRAPPIST-1 survive the star's superflares? Oct 28, 2024 [gif] Habitable planets around red dwarf stars might not get enough photons to support plant life Jan 15, 2019 [gif] The discovery of a new Earth-like planet could shed further light on what makes a planet habitable Jul 30, 2024 * Recommended for you [gif] Tiny Mars's big impact on Earth's climate: How the red planet's pull shapes ice ages 2 hours ago [gif] Mars was once a 'blue planet': Ancient river deltas point to vast ocean 5 hours ago [gif] Scientists find more active black holes in dwarf and Milky Way-sized galaxies by cutting through glare of star formation Jan 9, 2026 [gif] Study offers possible solution to a gravitational wave mystery Jan 8, 2026 [gif] Simultaneous packing structures in superionic water may explain ice giant magnetic fields Jan 8, 2026 [gif] The electrifying science behind Martian dust Jan 8, 2026 Load comments (1) Get Instant Summarized Text (Gist) Planets orbiting M-dwarf stars likely receive insufficient photosynthetically active radiation (PAR) to support the oxygen accumulation necessary for complex life. Modeling indicates that oxygenation on such worlds would take tens of billions of years, making the emergence of multicellular organisms improbable. Complex life is thus more likely around stars emitting higher-energy light. This summary was automatically generated using LLM. Full disclaimer Let us know if there is a problem with our content Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form. For general feedback, use the public comments section below (please adhere to guidelines). Please select the most appropriate category to facilitate processing of your request [-- please select one -- ] [ ] [ ] [ ] [ ] [ ] Your message to the editors [ ] Your email (optional, only if you'd like a response) [ ] Send Feedback Thank you for taking time to provide your feedback to the editors. Your feedback is important to us. However, we do not guarantee individual replies due to the high volume of messages. E-mail the story Complex life on planets orbiting the galaxy's most common stars may be unlikely Your friend's email [ ] Your email [ ] [ ] I would like to subscribe to Science X Newsletter. Learn more Your name [ ] Note Your email address is used only to let the recipient know who sent the email. Neither your address nor the recipient's address will be used for any other purpose. The information you enter will appear in your e-mail message and is not retained by Phys.org in any form. [ ] [ ] [ ] [ ] [ ] [ ] [ ] Your message [ ] Send Newsletter sign up Get weekly and/or daily updates delivered to your inbox. You can unsubscribe at any time and we'll never share your details to third parties. [ ] Subscribe More information Privacy policy Donate and enjoy an ad-free experience We keep our content available to everyone. Consider supporting Science X's mission by getting a premium account. Remove ads Maybe later Medical Xpress Medical Xpress Medical research advances and health news Tech Xplore Tech Xplore The latest engineering, electronics and technology advances Science X Science X The most comprehensive sci-tech news coverage on the web Newsletters [ ] Subscribe Science X Daily and the Weekly Email Newsletter are free features that allow you to receive your favorite sci-tech news updates in your email inbox Follow us * * * * * * * * Top * Home * Search * Mobile version * Help * FAQ * About * Contact * Support us * Science X Account * Archive * News wire * Android app * iOS app * RSS feeds * Push notification (c) Phys.org 2003 - 2026 powered by Science X Network Privacy policy Terms of use E-mail newsletter [ ] Subscribe Follow us * * * * It appears that you are currently using Ad Blocking software. What are the consequences? x Quantcast