Scientists are rethinking the possibility of life on tidally locked exoplanets, like LHS 3844b, which perpetually show one face to their star, creating extreme temperature divides. Despite searing heat on one side and absolute zero on the other, new research suggests these alien worlds could actually be more habitable than previously thought.
LHS 3844b, a planet slightly bigger than Earth located 48.5 light-years away, orbits a red dwarf star. Its tidally locked nature means one hemisphere is stuck in permanent daylight, while the other is plunged into eternal, frigid darkness. Initially, this seems like a recipe for un-livable conditions, with daytime temperatures soaring to 1,000-2,000 Kelvin and the night side reaching near absolute zero.
However, a study published in Nature Communications proposes that this extreme environment might not be a deal-breaker for life. Researchers found that tidal locking itself could help distribute heat, creating more moderate thermal zones. "Life might find a way," commented Daisuke Noto, a researcher involved in the study, highlighting that the planet's constant orientation might actually aid in sustaining life by managing heat flux.
The study also points out that tidally locked planets are far more common than planets like Earth with regular day-night cycles. Many celestial bodies close to their stars end up tidally locked, always presenting the same side, much like our moon does to Earth. The research team built a physical lab model, using glycerol and thermochromic liquid crystals in a tank, to simulate the interior of these planets and understand how heat moves within their rocky mantles.
Their experiments revealed a surprisingly stable pattern of heat distribution. Hot material consistently rose from beneath the day side, flowed to the cooler night side, and then sank, creating a continuous circulation loop. This steady, predictable internal "heartbeat" could potentially maintain localized geothermal environments, especially in the mid-latitudes, making some tidally locked exoplanets surprisingly hospitable.
Beyond surface temperatures, this internal circulation could even influence a planet's liquid core, potentially generating magnetic fields. While this aspect couldn't be tested in the current experiment, it opens exciting avenues for future research into the diverse conditions that could support life beyond our solar system.
