I was  playing as normal, then i heard a weird buzzing or slight rumbling sound, tried to pause to see if it was the game, it didn't let me. Then i looked outside, and a semi-bright light, sorta like the grays UFO, but white, appeared, moved closer to my radio tower (like 500+ feet far from it, from my guess) Then it just.. Popped out of existence with a sorta loud pop/woosh sound. No, it wasn't the "Sky Is Falling!" Event, already had that happen. Sadly no screenshot.. But i'm on around day 78 of playing. It let me pause as SOON as it was gone.