A collaborative effort between scientists at MIT, the University of Birmingham, and other institutions introduces a pioneering approach to identify potential extraterrestrial life and liquid water on distant planets. Instead of searching for specific chemical features in planetary atmospheres, researchers advocate examining the absence of certain chemicals as a key indicator.
The researchers propose that a terrestrial planet with significantly lower levels of carbon dioxide in its atmosphere, compared to other planets in the same system, could signal the presence of liquid water and potentially support life on its surface. This innovative signature, which suggests habitability, is notably detectable with NASA’s James Webb Space Telescope (JWST), setting it apart from other proposed signs of habitability that are challenging to measure with existing technologies.
Julien de Wit, an assistant professor of planetary sciences at MIT, emphasizes the significance of this new approach, stating that it provides a feasible way to determine if liquid water exists on other planets—a crucial step toward identifying habitable worlds. The researchers express confidence in the detectability of this carbon dioxide signature in the near future, presenting an exciting prospect for advancing our understanding of potential habitable environments beyond our solar system.
The study, co-led by de Wit and Amaury Triaud of the University of Birmingham, brings together a multidisciplinary team of scientists from various institutions, including MIT researchers like Benjamin Rackham, Prajwal Niraula, Ana Glidden Oliver Jagoutz, Matej Peč, Janusz Petkowski, and Sara Seager. The collaborative effort aims to provide a practical and accessible method for exploring the habitability of exoplanets in the coming years.
More than a fleeting glimpse
The quest for habitable exoplanets, where liquid water might exist, faces a significant breakthrough as scientists from MIT and the University of Birmingham explore a unique approach. While current telescopes can measure a planet’s orbital details and infer its potential habitability, directly confirming the presence of liquid water has remained elusive.
Drawing inspiration from our solar system, where liquid oceans are discernible through glints or flashes of sunlight reflecting off their surfaces, the researchers sought a similar observable trait in distant planets. Recognizing that Earth, among rocky planets like Venus and Mars, distinctly features lower levels of carbon dioxide in its atmosphere, the team identified this as a potential habitability indicator. The logic follows that a substantial reduction in atmospheric carbon dioxide suggests the removal of this gas through a robust water cycle, involving oceans of liquid water.
Amaury Triaud, co-lead of the study, notes that understanding the atmospheric composition of exoplanets, particularly their carbon dioxide levels, offers valuable insights into the potential existence of liquid water. While direct detection of glints remains technologically challenging, this novel approach opens a promising avenue for studying habitability in distant worlds. The researchers’ focus on deciphering the atmospheric signatures of exoplanets could pave the way for more detailed investigations, bringing scientists closer to identifying habitable environments beyond our solar system.
The Earth’s oceans have played a crucial role in regulating the planet’s atmosphere by absorbing substantial amounts of carbon dioxide over geological timescales. This process has left Earth’s atmosphere significantly less enriched with carbon dioxide compared to neighboring planets like Venus. Frieder Klein, a co-author of the study, emphasizes how the sequestration of atmospheric carbon dioxide in Earth’s oceans and solid rock has been instrumental in maintaining the planet’s climate and habitability for billions of years.
Building on this understanding, the research team posits that the detection of a similar depletion of carbon dioxide in the atmosphere of a distant planet, relative to its celestial neighbors, could serve as a reliable indicator of liquid oceans and potentially, life on its surface. The team’s reasoning draws from a comprehensive review of literature across various scientific disciplines, including biology, chemistry, and climate change studies, reinforcing their confidence that carbon depletion could be a robust signal of the presence of liquid water and, perhaps, life on distant exoplanets.
A journey through existence
The research team introduces a novel strategy for identifying habitable planets by focusing on a signature of depleted carbon dioxide, particularly applicable to systems with multiple terrestrial planets resembling our solar system. This approach, tailored for “peas-in-a-pod” planetary systems, involves the initial step of confirming the presence of atmospheres on these planets by detecting carbon dioxide, a prominent component in most planetary atmospheres.
Julien de Wit highlights the effectiveness of carbon dioxide detection, emphasizing its strong infrared absorption properties, making it easily discernible in exoplanet atmospheres. Once astronomers ascertain atmospheric presence on multiple planets within a system, the team proposes a detailed examination of their carbon dioxide content. Significantly lower carbon dioxide levels in one planet compared to others would indicate potential habitability, suggesting the presence of substantial liquid water on its surface.
While habitable conditions are a promising indicator, the team acknowledges that this alone does not confirm the existence of life. To explore the possibility of life, astronomers are advised to look for another key feature in a planet’s atmosphere: ozone. On Earth, the researchers note that plant life and certain microbes contribute to carbon dioxide reduction, emitting oxygen in the process. This oxygen interacts with solar photons to produce ozone—a molecule that is more easily detectable than oxygen itself. This two-step approach, involving carbon dioxide analysis and ozone detection, offers a comprehensive strategy for identifying potentially habitable and, intriguingly, inhabited planets beyond our solar system.
The researchers propose a conclusive method for identifying habitable and potentially inhabited planets by examining their atmospheres for the presence of both ozone and depleted carbon dioxide. If a planet displays these dual characteristics, it signals a high likelihood of being habitable and hosting life.
Amaury Triaud emphasizes that the detection of ozone is a crucial indicator, as it suggests a connection to carbon dioxide consumption by living organisms. This points not just to the existence of minimal bacterial life but to the potential presence of a planetary-scale biomass capable of processing substantial amounts of carbon. The prospect of identifying such significant and interacting life forms beyond Earth adds an extra layer of excitement to the search for habitable exoplanets.
The researchers identify NASA’s James Webb Space Telescope (JWST) as a powerful tool capable of measuring carbon dioxide and potentially ozone in nearby multi-planet systems like TRAPPIST-1. This seven-planet system, orbiting a star just 40 light years away, offers a promising opportunity for terrestrial atmospheric studies using the JWST. Julien de Wit envisions collaborative efforts leading to paradigm-shifting discoveries in the coming years, especially with a focused approach on systems like TRAPPIST-1, providing a roadmap for the exploration of habitable planets in our cosmic neighborhood.
Resources
- ONLINE NEWS Chu, J. & Massachusetts Institute of Technology. (2023, December 29). A carbon-lite atmosphere could be a sign of water and life on other terrestrial planets, study finds. Phys.org. [Phys.org]
- JOURNAL Triaud, A. H. M. J., de Wit, J., Klein, F., et al. (2023). Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets. Nature Astronomy. [Nature Astronomy]
Cite this page:
APA 7: TWs Editor. (2023, December 29). How a Carbon-Lite Atmosphere Can Hint at the Presence of Water and Life on Other Terrestrial Planets, According to a Study? PerEXP Teamworks. [News Link]
