On August 1, 1983, the Earth experienced a significant disturbance in its atmosphere due to a gamma ray burst (GRB) believed to have originated from the explosion of a nearby massive star. This event had a noticeable effect on low-frequency radio waves traveling around the planet by disturbing the lower ionosphere, a partially ionized region of the atmosphere.
In the past 40 years, astronomers have observed more than one GRB per day, yet none seemed to have a noticeable impact on the atmosphere until a bright GRB on October 9, 2022, was associated with a disturbance in the uppermost ionosphere. This finding was presented in a study published in Nature Communications by lead author Mirko Piersanti, a space weather scientist at the University of L’Aquila and the Italian National Institute of Astrophysics.
According to Piersanti, the detection of such an impact poses a threshold problem, as only very powerful GRBs can ionize enough of the low-density upper atmosphere for long enough to be noticeable. This presents a challenge in distinguishing cosmic gamma rays from other phenomena affecting the region.
In addition to its significance in astrophysics, understanding the impact of GRBs holds potential human stakes, particularly in relation to the increasing amount of infrastructure and economy in space. This includes the potential risk to satellites, electrical power grids, and global systems due to disturbances caused by solar events and cosmic phenomena like GRBs.
The study also revealed that the ionosphere is a key component in this issue and that understanding the effects of cosmic events on the ionosphere is essential. However, data collection and measurements from the ionosphere pose a challenge, given the difficulty of obtaining global, 24-hour views.
With only two GRBs as reference points, scientists are calling for wider collaborations between various research fields to further understand the impact of cosmic events on the ionosphere. The ultimate goal is to enhance our ability to detect and predict such effects in the future.
In summary, the study sheds light on the impact of powerful cosmic events on the Earth’s atmosphere and the importance of further research to understand and potentially mitigate any related risks to our infrastructure and technology.