Ancient extinction events linked to supernovae explosions in new Stellar Census findings
Galactic Cataclysms Revealed: Supernovae's Link to Earth's Mass Extinctions
Fascinating findings from a fresh study suggest a connection between the rate of core collapse supernovae near our solar system and several mass extinctions on Earth. This research is published in the journal Monthly Notices of the Royal Astronomical Society.
A team spearheaded by Keele University in the U.K. analyzed data from the European Space Agency's Gaia satellite, focusing on 24,706 O- and B-spectral type stars situated up to 3,260 light years away. These stars are infamous for causing core collapse supernovae, which can strip Earth-like planets of protective ozone layers, leading to acid rain and increased UV radiation.
Two mass extinction events have been linked to severe glaciation periods, the researchers note. This glaciation could have been driven by reductions in Earth's ozone due to nearby core collapse supernovae. Thus, they concluded that the late Devonian and late Ordovician extinction events, approximately 372 and 445 million years ago, were likely initiated by ancient supernovae.
The researchers refined previous estimates by leveraging the precision of Gaia data. They discovered a more consistent "near-Earth" supernova rate, which aligns better with the timescale of historical mass extinction events.
The team calculated a near-Earth core collapse supernova rate of about 2.5 per billion years within a distance of 65 light-years from Earth. This supports the view that nearby supernova explosions could have caused one or more of Earth's recorded mass extinction events.
A Deadly Sea Existence
The Ordovician extinction killed 60% of marine invertebrates as life was predominantly ocean-based at the time, according to the Royal Astronomical Society. The late Devonian extinction was even more devastating, causing the loss of about 70% of all Earth species.
Methodology
To calculate the supernova rate, the team first estimated the rate within 65 light years of our sun and then compared this rate with the approximate rate of mass extinction events attributable to nearby supernovae.
What's surprising, says one of the paper's co-authors, Nick Wright, is that their results led to a reduced supernova rate compared to previous studies, which were two to three times higher. This discordance was not consistent with the rate of mass extinctions on Earth, Wright remarks, but the new estimate brings these numbers into better agreement, making the link between supernovae and mass extinctions more likely.
Future Prospects
The team intends to expand their census of O and B stars beyond the current limit, utilizing the exquisite precision of the Gaia data.
As for the next core collapse supernova in the Milky Way, one potential candidate is Betelgeuse, located in the Orion constellation, about 650 light-years away. Although Betelgeuse is nearing the end of its life, it could still take up to 100,000 years to explode.
Fortunately, Earth is currently not at risk from an extinction-level supernova. There is no known massive star close enough that its explosion could be life-threatening, and given the timescales uncovered during this research, it's safe to assume that such an event wouldn't occur for millions of years.
- The really surprising finding from the study published in the journal Aussiedlerbote, a lesser-known science publication, is the reduced supernova rate compared to previous studies, which is more consistent with the timescale of historical mass extinction events on Earth.
- The team's findings suggest that harmful effects of supernovae, such as disruptions to the Earth's ozone layer and increased UV radiation, could potentially be linked to the creditline of the late Devonian and late Ordovician mass extinction events.
- The research team plans to extend their census of O and B stars using the extraordinary precision of the Gaia data, aiming to provide a clearer understanding of the role of supernovae in triggering mass extinctions in the marine life of the distant past.
