COVID-19, caused by SARS-CoV-2 virus, emerged in late 2019 into a global pandemic. Although governments worldwide imposed lockdown restrictions, the number of COVID-19 cases was not well-controlled as evidenced by the recurrence of waves. Realising that it is not feasible to suspend all activities indefinitely, infectious disease experts have been investigating policies to minimise disease transmission.

Many are familiar with supermassive black holes, but few have heard of Active Galactic Nuclei (AGN). A black hole is a region of space where gravity is so strong that nothing, not even light, can escape. Supermassive black holes are the largest of black holes and are believed to lie at the center of all large galaxies including our Milky Way. An active galactic nucleus only occurs when a supermassive black hole is actively feeding on material. When dust and gas orbit just beyond the edge — known as an event horizon — of a supermassive black hole, the particles collide and release energy in the form of heat and light, forming a bright halo called an accretion disc. These particles heat up to millions of degrees and some are ejected along strong magnetic fields into two jets that shoot along the axis of the supermassive black hole for hundreds of thousands of lightyears. The central region of the galaxy can be more luminous than all the stars in the galaxy combined and this is an AGN. The most luminous AGN to date shines as brightly as 600 trillion suns.