A recent study suggests that violent supernova explosions could be linked to two of Earth’s most significant unexplained mass extinctions. The research indicates that such stellar events may have influenced Earth’s environment during the past billion years, particularly impacting life on the planet.
Supernovae occur during the dying phases of massive stars, resulting in a catastrophic explosion that obliterates the star and releases vast amounts of material and radiation into space. A research team has examined the frequency of supernovae near our solar system, specifically targeting stars within a 65-light-year radius. They estimate that approximately 2.5 supernovae could have had an impact on Earth over the last billion years, which translates to one or two incidents during the past 500 million years of evolutionary history.
This investigation forms part of a broader analysis of rare, short-lived O- and B-type stars in the Milky Way, utilising data from the European Space Agency’s Gaia space telescope. The findings prompted the researchers, led by physicist Wright, to propose connections between these cosmic phenomena and mass extinction events, suggesting that supernovae may have played a role in the Late Devonian extinction around 372 million years ago and the end of the Late Ordovician extinction 445 million years ago.
The hypothesis revolves around the idea that supernovae can strip the Earth’s ozone layer, which protects against harmful radiation, potentially triggering a series of catastrophic events leading to extinctions. Past geological records reveal that during the Devonian period, the emergence of early land plants and animals was significantly disrupted, while the Ordovician extinction eliminated about 85% of marine species at that time.
Experts in the field express caution about these findings, acknowledging the need for tangible evidence that aligns the timing of supernovae with known extinction events. Previous planetary extinction events, such as the one that eradicated the dinosaurs, have been linked to asteroid impacts, showcasing the necessity for a similar conclusive “smoking gun” for the supernova theory, potentially in the form of rare elements like iron-60 found in ancient sediments.
This study highlights the duality of massive stars as both creators and destroyers of life. While the notion remains speculative, researchers aim to encourage further investigation into the potential impacts of cosmic events on Earth’s ecological history, underscoring the significance of supernovae in the lifecycle of our planet. While they hope to substantiate their claims with additional research, any definitive connections between supernovae and mass extinctions remain to be uncovered.