Scientists at the University of L’Aquila and the Italian National Institute of Astrophysics made a groundbreaking discovery linking a powerful gamma ray burst on October 9, 2022, with a disturbance in Earth’s uppermost ionosphere. This finding is significant because for over 40 years, astronomers have observed an average of more than one gamma ray burst per day without noticing any noticeable impact on the atmosphere. The study was published in Nature Communications, and the lead author, Mirko Piersanti, described the phenomenon as a “threshold problem” where only the most powerful gamma ray bursts have the potential to ionize the low-density upper atmosphere enough to be detectable.
Aside from its implications for astrophysics, this discovery also has potential implications for human infrastructure and economy. Atmospheric scientist Aaron Breneman from NASA’s Goddard Space Flight Center stated that with an increasing amount of infrastructure and economy in space, the potential risk from cosmic events like gamma ray bursts is of global concern. In addition, there is speculation that a powerful gamma ray burst may have contributed to a mass extinction event about 450 million years ago. Therefore, understanding the magnitude of this threat and its potential impact on Earth is crucial.
Previous attempts to detect gamma ray bursts’ impact on the ionosphere have been largely unsuccessful due to the extreme distance of these events and their short duration. The photoionization rate from the gamma ray bursts needs to be at least 5 times faster than recombination for their effect to be detectable in the ionosphere. Additionally, factors such as the Sun, Earth’s own storms, and lightning can influence ionization in the upper atmosphere, making it difficult to isolate the effects of gamma ray bursts.
With only two gamma ray bursts to analyze, researchers have emphasized the need for wider collaborations among various scientific disciplines to better understand the impact of cosmic events on Earth’s atmosphere. Overall, the 2022 gamma ray burst has provided valuable data for further research, shedding light on the potential effects of these powerful cosmic phenomena on our planet.