Free Astronomy Magazine July-August 2024

7 JULY-AUGUST 2024 ASTRO PUBLISHING reaches the Earth for the fastest flows. The only certainty we have is that geomagnetic storms increase with solar activity and characterize all solar cycles. A study published at the beginning of 2020 in Geophysi- cal Research Letters reports that in the last 150 years there have been 42 “severe” category geomagnetic storms (like the one in 2022) and six “super” category geomagnetic storms (like that of last May and those of 2003 and 1989, which pro- duced heavy blackouts). If these categories were the only possible ones, we would have noth- ing to worry about beyond tempo- rary inconveniences that are easy to resolve. Unfortunately, this is not the case. A well-documented histor- ical episode reminds us that much S pectacular effects of last May’s geomagnetic storm, imaged by Evan Boyce on the coast of Northern Ireland. [Evan Boyce] more dramatic geomagnetic storms can occur. This episode is known as the “Carrington Event.” Richard Christopher Carrington was a 19 th century English amateur as- tronomer, particularly dedicated to the observation of sunspots. In the late morning of September 1 st , 1859, from his observatory in Redhill, just south of London, he was drawing a large group of sunspots when two small, extremely bright, bean- shaped areas appeared within that photospheric structure. Within five minutes, those very bright spots faded and disappeared, after appar- T his destructive reentry of an ESA cargo ship into the Earth’s atmosphere effectively illustrates what could happen to numerous low-orbit satel- lites if a Carrington-type or even more violent event were to occur today. [ESA/NASA]