Has the Earth been exposed to numerous supernovae within the last 300 kyr?

Firestone (2014) asserted evidence for numerous (23) nearby (d<300 pc) supernovae within the Middle and Late Pleistocene. If true, this would have strong implications for the irradiation of the Earth; at this rate, mass extinction level events due to supernovae would be more frequent than 100 Myr. However, there are numerous errors in the application of past research. The paper overestimates likely nitrate and 14C production from moderately nearby supernovae by about four orders of magnitude. Moreover, the results are based on wrongly selected (obsolete) nitrate and 14C datasets. The use of correct and up-to-date datasets does not confirm the claimed results. The claims in the paper are invalidated.

💡 Research Summary

The paper challenges the claims made by Firestone in 2014 that numerous supernovae (around 23) have occurred within a close proximity (d<300 pc) to Earth over the last 300,000 years. If true, this would imply significant irradiation of Earth and suggest mass extinction-level events due to supernovae could occur more frequently than once every 100 million years. However, the current analysis identifies several critical issues with Firestone’s methodology. The paper overestimates the production of nitrates and carbon-14 from moderately nearby supernovae by about four orders of magnitude. Moreover, the results are based on outdated datasets that were incorrectly selected for this purpose. When using correct and up-to-date datasets, the findings do not support Firestone’s claims. Consequently, the paper concludes that the assertions made in Firestone (2014) are invalid due to these methodological errors and misinterpretations of data.