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Solar flares may change the weather on distant worlds—and maybe even ours

A new study has uncovered a connection between solar flares—sudden outbursts of radiation from stars—and short-term weather patterns on distant Earth-like planets.

Published in The Astronomical Journal, the offers the clearest evidence yet that space weather—particularly flares from a planet's host star—can cause measurable changes in a planet's climate within just days of an event. These findings provide important clues about the habitability of exoplanets and may even help refine how we understand short-term atmospheric shifts on Earth.

The research team was led by scientists from the Hebrew University of Jerusalem, NASA, the Florida Institute of Technology, the Barcelona Supercomputing Center, and the University of Oxford.

"This study highlights an underexplored but important solar-climate link," said Dr. Assaf Hochman, from the Institute of Earth Sciences at Hebrew University. "While anthropogenic greenhouse gases primarily drive long-term climate change, we now see that short-term solar variability can also play a role in modulating regional climate behavior."

The international team—including Dr. Assaf Hochman, Dr. Howard Chen, Dr. Paolo De Luca, and Dr. Thaddeus D. Komacek—used advanced 3D General Circulation Models to simulate how sudden flares from host stars affect the climate on tidally locked exo-Earths such as TRAPPIST-1e, a planet that always shows the same face to its sun.

Their results reveal a chain reaction:

• Upper atmospheric cooling occurs quickly after a flare, driven by radiative emissions from molecules like NO and CO₂.
• Simultaneously, lower atmospheric warming happens due to increases in greenhouse-like gases such as H₂O and N₂O.
• Wind speeds in the middle atmosphere can intensify dramatically—surging to over 140 km/h on the dark, night side of the planet.

What it means for Earth—and beyond

While the main focus was on distant worlds, the study opens up provocative possibilities for Earth's climate systems too.

The patterns observed suggest that solar activity may temporarily alter a planet's general atmospheric circulation. This isn't about long-term climate shifts, but rather short-lived regional anomalies—the kind that could be especially noticeable in already volatile weather zones.

The research emphasizes that while solar flares aren't a major driver of Earth's long-term climate compared to human activity, their effects are real, detectable, and worth factoring into future atmospheric models. This is particularly true when considering regions sensitive to abrupt changes in temperature and wind.

The study also underscores that stars don't just warm their planets—they can stir up the weather too. Understanding these interactions is crucial to assessing which exoplanets might truly be capable of supporting life.

This interdisciplinary effort brought together experts in astroclimate modeling, atmospheric chemistry, and planetary science, with support from institutions across four countries and multiple NASA research centers. Their findings not only enhance our understanding of distant exoplanets but could also help us refine how we predict and prepare for solar influences here on Earth.