Researchers from Keele University have identified evidence linking two significant mass extinction events—the Ordovician (~445 million years ago) and the late Devonian (~372 million years ago)—to nearby supernova explosions. These cosmic events likely caused ozone layer depletion, acid rain, and increased UV radiation, resulting in substantial loss of marine life.

The study, published in the Monthly Notices of the Royal Astronomical Society, involved a census of massive OB stars within approximately 3,260 light-years from Earth to determine the supernova rate near our planet. This calculated rate aligned with the timing of the extinction events, reinforcing the theory that supernovae were responsible. Currently, only two nearby stars, Antares and Betelgeuse, could potentially go supernova in the next million years; however, their distance exceeds 500 light-years, posing no immediate threat to Earth.

Supernovae and Earth’s Past Extinctions: Understanding Cosmic Threats

Supernovae, the explosive deaths of massive stars, have left an indelible mark on Earth’s history. These cosmic events, capable of releasing gamma rays and high-energy particles, have been implicated in past mass extinctions, such as the Ordovician-Silurian and Late Devonian events. By stripping away portions of Earth’s atmosphere and inducing climate changes, supernovae have reshaped the planet’s biodiversity, leaving ecosystems scarred by their violent impacts.

Recent research by Alexis Quintana and Nicholas Wright has focused on OB stars within 1 kiloparsec of the Sun—massive, short-lived stars that are progenitors of core-collapse supernovae. Their study provides critical insights into nearby supernova events’ frequency and potential impact. Currently, prominent candidates like Antares and Betelgeuse are located over 500 light-years away, well beyond the threshold for significant impact on Earth, which is estimated to be around 100-200 light-years.

While immediate threats from nearby supernovae appear minimal, understanding their role in past extinctions is vital for developing strategies to mitigate future risks. By studying these cosmic phenomena, scientists can better predict and prepare for events that could threaten Earth’s biodiversity. This knowledge informs the development of early warning systems and enhances our ability to protect ecosystems from astronomical hazards.

Quintana and Wright’s study involved a comprehensive census of OB stars within 1 kiloparsec, offering insights into historical supernova rates in the Milky Way. Their findings suggest that while current threats are low, ongoing surveillance of these stars is essential for proactive preparation. Despite the minimal risks nearby supernovae pose today, their short lifespans mean they could pose future dangers, underscoring the importance of continued monitoring.

Violent supernovae were responsible for at least two mass extinction events on Earth: the Ordovician-Silurian extinction around 450 million years ago and the Late Devonian extinction approximately 370 million years ago. Both events caused substantial losses of marine species, reshaping the planet’s biodiversity. By understanding these past impacts, scientists can better prepare for future cosmic events that could threaten life on Earth.

While immediate threats from nearby supernovae are low, this research highlights the importance of understanding cosmic phenomena to safeguard Earth’s ecosystems. By staying vigilant and leveraging scientific insights, humanity can enhance its ability to protect the planet from potential astronomical hazards, ensuring a safer future for Earth’s biodiversity.