Imagine a time when our Sun was a wild, unruly teenager, spewing out massive bursts of energy that could have shaped the very beginnings of life on Earth. This is the fascinating, yet largely unexplored, story of our Sun’s early days—and it’s one that astronomers are now piecing together by studying its younger, more volatile cousins in the cosmos.
Our Sun, as we know it today, occasionally releases powerful bursts of plasma called coronal mass ejections (CMEs). These events, accompanied by strong magnetic fields, can wreak havoc on Earth’s technology, disrupting satellites and power grids. But here’s where it gets even more intriguing: billions of years ago, when our solar system was young, the Sun was far more active, unleashing CMEs of unimaginable scale. Could these ancient eruptions have influenced the emergence and evolution of life on our planet? Some researchers believe so, but proving it requires a creative approach.
Since we can’t travel back in time to observe the early Sun, astronomers turn to the next best thing: young stars that resemble our Sun in its youth. These so-called ‘exo-suns’—G-, K-, and M-type stars—are far more active than our middle-aged Sun, frequently producing CMEs with energies dwarfing anything we’ve seen in recent history. But here’s where it gets controversial: while these eruptions could shape the atmospheres of their planets, they might also alter the very chemistry of those worlds, potentially affecting their habitability.
Until recently, studying these stellar eruptions has been like trying to spot a firefly in a fireworks display. The intense brightness of the stars themselves often masks the signatures of these events. However, a breakthrough came in March 2024, when astronomers at Kyoto University detected a Carrington-class superflare from EK Draconis, a young G-type star located 112 light-years away. And this is the part most people miss: by using simultaneous observations in ultraviolet and optical wavelengths, they uncovered the first direct evidence of a multi-temperature CME from a star like our young Sun.
Over four nights, the team used the Hubble Space Telescope, the Transiting Exoplanet Survey Satellite (TESS), and ground-based telescopes to monitor the event. They discovered that hot plasma, reaching temperatures of 100,000 K, was ejected at speeds of up to 550 km/s, while cooler gases (10,000 K) moved at a more leisurely 70 km/s. This finding suggests that it’s the hot plasma, not the cooler material, that carries the bulk of the energy into planetary space—a revelation that could rewrite our understanding of how early solar eruptions impacted Earth and other planets.
Study leader Kosuke Namekata explains, ‘If our Sun produced frequent and powerful CMEs in its youth, these could have driven shocks and energetic particles capable of eroding or chemically altering the atmospheres of early Earth and other planets.’ This discovery not only bridges the gap between solar and stellar physics but also opens new avenues for exploring the origins of life in our solar system.
Looking ahead, researchers plan to expand their studies to other young solar analogues, aiming to understand how often these eruptions occur and how they vary across stars. With next-generation ultraviolet telescopes like JAXA’s LAPYUTA and NASA’s ESCAPADE on the horizon, we’re on the cusp of systematically tracing these events and their cumulative effects on planetary atmospheres.
But here’s a thought-provoking question for you: If these massive CMEs shaped life on Earth, could they also be the key to finding life on other planets? Or might they be a double-edged sword, capable of both fostering and destroying habitability? Share your thoughts in the comments—this is a conversation that’s just getting started.