#AstroClimate

[lifesciencesmagazine]

Galactic Journey May Have Shaped Earth’s Climate Millions of Years Ago

Source: scienceblog.com

A Cosmic Encounter with the Radcliffe Wave

Scientists suggest that Earth’s climate may have been influenced by an interstellar event that occurred 14 million years ago. As the solar system orbits the center of the Milky Way, it moves through various cosmic regions, one of which might have played a role in Earth’s climatic shift. According to a recent study, our solar system passed through a dense, star-forming area near the Orion constellation, a region structured into what astronomers call the Radcliffe Wave. This wave is a massive network of star clusters spanning nearly 9,000 light-years and was identified in 2020 through data from the European Space Agency’s Gaia telescope.

During this passage, scientists believe the Earth may have been exposed to a higher concentration of interstellar dust. This aligns with a significant climatic transformation on Earth—the expansion of the Antarctic Ice Sheet, marking a shift from a warmer climate to a cooler one. Researchers theorize that the influx of cosmic dust could have contributed to this transition alongside other natural factors. If verified, this discovery could provide a new perspective on how extraterrestrial influences have shaped Earth’s geological and climatic history.

Investigating the Evidence of Extraterrestrial Dust

To validate this hypothesis, scientists are searching for geological evidence of a cosmic dust influx from 14 million years ago. A key indicator would be elevated levels of certain radioactive elements, particularly iron-60, a rare isotope primarily associated with supernovae. If researchers can identify an ancient spike of iron-60 in Earth’s sediment layers, it would strengthen the case for interstellar dust influencing Earth’s climate. However, detecting this element is challenging, as the isotope has a half-life of just 2.6 million years, making traces difficult to locate after such a long period.

Lead researcher Efrem Maconi and his team published their findings in Astronomy & Astrophysics, where they outlined the cosmic journey of the solar system and its proximity to dust-rich star clusters NGC 1980 and NGC 1981. Their simulations suggest that the solar system remained in this dense region for roughly one million years. During this time, increased interstellar dust could have partially blocked sunlight, potentially contributing to the planet’s cooling phase. While scientists acknowledge that other climatic forces were also at play, the correlation in timing presents an intriguing case for further study.

Unraveling the Past and Looking to the Future

Despite the difficulty in tracing ancient cosmic dust on Earth, researchers believe that other celestial bodies might hold more stable records. The Moon, for instance, lacks geological recycling processes like those on Earth, making it a potential site for preserving interstellar dust deposits. Craters near the lunar poles, which remain cold and undisturbed, could contain crucial evidence that scientists are eager to explore.

While the study presents a compelling scenario, experts caution that extraordinary claims require extraordinary evidence. Determining whether interstellar dust significantly impacted Earth’s climate will require advancements in both geological analysis and astronomical observations. Nevertheless, this research offers a new perspective on the deep connections between cosmic events and planetary evolution. As technology improves, future studies may uncover more definitive proof of how our galactic environment has shaped Earth’s past and continues to influence its future.

[spacetimewithstuartgary]

Sun’s fury may change the weather on distant worlds — and maybe even ours

A new study led by scientists from the Hebrew University of Jerusalem, NASA, the Florida Institute of Technology, the Barcelona Supercomputing Center, and the University of Oxford 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 study 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.

“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.

IMAGE: Temporal medians of "extreme," "moderate," and "quiescent" simulations for Temperature (T in K). Credit: The Astronomical Journal (2025). DOI: 10.3847/1538-3881/add33e