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New Stellar Census Links Supernovae with Two Ancient Extinction Events
A groundbreaking new census of massive stars in our part of the Milky Way Galaxy has uncovered a shocking link between core collapse supernovae and two ancient mass extinction events on Earth. The research, published in Monthly Notices of the Royal Astronomical Society, challenges previous estimates and suggests that nearby supernova explosions could have triggered devastating extinctions.
Using data from the European Space Agency’s Gaia satellite, a team led by Keele University in the U.K. mapped and characterized 24,706 O- and B-spectral type stars out to distances of some 3200 light years. These stars are responsible for the catastrophic core collapse supernovae that can strip earthlike planets of their atmospheric ozone, create acid rain, and leave surfaces exposed to harmful ultraviolet radiation.
The research reveals a striking correlation between the rate of nearby supernovae and two mass extinction events: the late Devonian and late Ordovician extinctions. These catastrophes wiped out 70% and 60% of all Earth species, respectively. The authors propose that dramatic reductions in atmospheric ozone levels could have been driven by intense glaciation periods triggered by core collapse supernovae.
Previous studies had estimated a higher rate of nearby supernovae, but the new census has significantly reduced this estimate to approximately 2.5 supernovae over a billion-year period. This revised rate aligns with the timescale of recorded mass extinction events on Earth.
To reach their conclusions, the researchers calculated the supernova rate within 65 light years of our sun, comparing it with the approximate rate of mass extinction events that have been attributed to nearby supernovae in the past. The study’s lead author notes that this new estimate brings the numbers into better agreement, making a link between supernovae and extinctions more plausible.
The research has far-reaching implications for our understanding of the history of life on Earth. By extending the census beyond its current limitations, the team aims to further refine their findings and potentially uncover additional connections between astronomical events and mass extinction events.
