Could alien life thrive without a circadian rhythm? Insights from Earth’s hidden organisms.

  • Many potentially habitable planets lack a day-night cycle, affecting the evolution of life.
  • M-dwarf stars, which are cooler and smaller, host a significant number of planets in their habitable zones.
  • Tidally locked planets, like M-Earths, have one side always facing their star, leading to unique environmental conditions.
  • Life on Earth, such as cave-dwellers and deep-sea organisms, shows that biorhythms can exist without light.
  • Research suggests that M-Earths may have cycles that replace traditional days and seasons, influencing potential life forms.

Research indicates that many planets capable of supporting life may not experience a traditional day and night cycle, which could significantly influence the evolution of any potential life forms. On Earth, organisms that thrive in lightless environments, such as those found deep underground or at the ocean’s depths, provide clues about what life might look like on these alien worlds. The Milky Way is home to billions of potentially habitable planets, particularly around M-dwarf stars, which are cooler and smaller than our sun. A 2013 survey estimated that about 41% of these stars have planets in their ‘Goldilocks’ zone, where conditions might allow for liquid water. This translates to approximately 28.7 billion planets that could potentially support life. However, these M-Earths differ fundamentally from our own planet. Due to their proximity to their stars, they are likely tidally locked, meaning one side always faces the star while the other remains in perpetual darkness. This results in a unique environment where traditional concepts of day, night, and seasons do not apply. On Earth, life has evolved with circadian rhythms that are closely tied to the day-night cycle, affecting everything from sleep patterns to immune responses. Yet, organisms like naked mole rats and deep-sea creatures demonstrate that life can adapt to environments devoid of light, often synchronizing their biological rhythms to other stimuli such as temperature changes or tidal movements. Recent studies suggest that M-Earths could have their own cycles, driven by atmospheric conditions rather than rotation. These cycles might influence the evolution of life forms, potentially leading to species that migrate between the planet’s sunlit and dark sides. The possibility of life on these planets challenges our assumptions about biology and evolution, suggesting that if life exists elsewhere, it may be vastly different from what we know.·

Factuality Level: 8
Factuality Justification: The article presents a well-researched exploration of the potential for life on tidally locked planets, supported by scientific studies and examples from Earth. It avoids sensationalism and provides a balanced view of the topic. However, some speculative elements about alien life and biorhythms could be seen as less factual, which slightly lowers the rating.·
Noise Level: 8
Noise Justification: The article provides a thoughtful analysis of the potential for life on tidally locked planets, supported by scientific data and examples from Earth’s organisms. It explores the implications of these findings on our understanding of life and biorhythms, while remaining focused on the topic without irrelevant information. However, it could benefit from more actionable insights or solutions.·
Key People: Maureen Cohen (Postdoctoral Research Associate in Venus Global Climate Modelling at The Open University)

Financial Relevance: No
Financial Markets Impacted: No
Financial Rating Justification: The article discusses the possibility of life on tidally locked planets and their potential biorhythms, which does not have a direct impact on financial markets or companies.
Presence Of Extreme Event: No
Nature Of Extreme Event: No
Impact Rating Of The Extreme Event: No
Extreme Rating Justification: The article discusses theoretical concepts regarding alien life and planetary conditions but does not mention any extreme events that occurred in the last 48 hours.·
Move Size: No market move size mentioned.
Sector: All
Direction: Neutral
Magnitude: Small
Affected Instruments: No

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