I would ask the aliens what mysteries they are still trying to solve,(reply>), @Whiskey Sour you do realize covid spreads through things such as saliva from coughing? It stops the saliva from jumping to other people when you sneeze , cough or talk.,(reply>), @KIRBEATS How big is a Covid particle, and how big are the pores in your mask, smarty?,(reply>), @Whiskey Sour take a mask and run it under water. Then really wonder if this was a smart question,(reply>), ...how humans are capable of figuring out Physics, but also think a piece of fabric over their mouth protects them from a virus?