The Sun’s powerful plasma bursts, known as coronal mass ejections (CMEs), may have been essential to the rise of life on Earth, according to new research by Japanese scientists.
CMEs and solar flares erupt from our Sun to drive space weather, which can have significant effects on Earth’s magnetosphere, including auroras, geomagnetic storms, and disruptions to our electrical and communications infrastructure.
But it wasn’t only our modern technological society that has been shaped by these phenomena. Earlier research on young stars similar to our early Sun revealed that such stars produce far more powerful flares than those observed today, although these studies did not specifically address CMEs.
Solar System-Wide Impact
Earth was not alone. The power of a younger, more active Sun would have similarly influenced the early environments of Earth, Mars, and Venus. While researchers agree that solar flares played a major role in this planetary transformation, the effects of CMEs remain less understood.
Although modern instruments have observed relatively cool CME plasma, the speeds and frequency of strong CMEs in the distant past are still uncertain.
“What inspired us most was the long-standing mystery of how the young Sun’s violent activity influenced the nascent Earth,” said lead author Kosuke Namekata of Kyoto University. “By combining space- and ground-based facilities across Japan, Korea, and the United States, we were able to reconstruct what may have happened billions of years ago in our own solar system.”
Investigating Coronal Mass Ejections
To explore this question, the team studied EK Draconis, a young solar analogue, combining optical data from ground-based telescopes in Japan and Korea with ultraviolet observations from NASA’s Hubble Space Telescope.
Each data stream revealed a different part of the star’s activity: ground-based observations traced cooler hydrogen gas through the Hα line, while Hubble tracked hotter plasma in the far-ultraviolet spectrum. Together, these datasets were used in multi-wavelength spectroscopic analyses that allowed researchers to observe the dynamics of an ejection’s hot and cool components in real time.
The analysis uncovered the first evidence of EK Draconis producing a multi-temperature coronal mass ejection. According to the team, the CME occurred in two stages: an initial phase that ejected plasma at about 100,000 K and speeds between 300 and 550 kilometers per second, followed by a cooler second phase at 10,000 K moving more slowly at roughly 70 kilometers per second.
The initial, hotter stage carried far greater energy, suggesting that frequent CMEs from the young Sun could have generated powerful shocks and energetic particles capable of eroding or chemically altering early planetary atmospheres.
Exploring the Emergence of Life
Previous theoretical and experimental studies have shown that energetic particles and CMEs can significantly affect both greenhouse gases and the formation of complex biomolecules—key ingredients for life. These findings have important implications for understanding how life arose on Earth and potentially elsewhere in the universe.
Given the scope of such research, the team emphasized the importance of continued international collaboration at a time when science funding faces uncertainty. Instruments across several countries were essential to their discovery.
“We were happy to see that, although our countries differ, we share the same goal of seeking truth through science,” Namekata said.
The paper, “Discovery of Multi-temperature Coronal Mass Ejection Signatures from a Young Solar Analogue,” appeared in Nature Astronomy on October 27, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.