New theory says supernovae caused extinction events on Earth

According to a new study published this week by researchers at the University of Illinois, a nearby star’s supernova may’ve caused one of out planets mass extinctions millions of years ago. The event studied here took place in the Late Devonian, “culminating in extinction events near the Devonian-Carboniferous boundary.” Evidence shown in the study published this week suggests that asteroids weren’t the only thing that killed massive amounts of life on Earth in the distant past.

Per the research, the final extinction event of the Devonian period, ending around 358.9 Mya, seemed to have coincided with a dramatic drop in stratospheric ozone, “possibly due to a global temperature rise.” The suggestion in this research is that a nearby supernova explosion caused the whole catastrophic series of events that ended gigantic masses of life on Earth.

A supernova explosion “could inflict damage by accelerating cosmic rays that can deliver ionizing radiation for up to (approximately) 100 ky.” Researchers proposed the possibility that a supernova taking place at approximately 20 pc, beyond the initial “kill distance” of a supernova, could still have “precipitated a full mass extinction” on our planet.

This research suggested that a near-earth core collapse supernovae (SSNe) of a star could have occurred in the Devonian period, and that more than one SSNe could have occurred, causing multiple stages of extinction in the period, including the Kellswasser (extinction pulse event), and the Hangenberg event. Evidence shown in the research shows associations with ozone depletion.

Previous sources had pointed to the possibility that ozone depletion was caused by volcanic eruption and a large igneous province (LIP), but no known work had explored astrophysical sources of ionizing radiation for this period.

For more information on this research, see the paper “Supernova triggers for end-Devonian extinctions” with code DOI:10.1073/pnas.2013774117. This research was authored by Brian D. Fields et. al and published by PNAS on August 18, 2020.

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