The first period-41 oscillator in Conway's Game of Life was just found by Nico Brown: https://conwaylife.com/forums/viewtopic.php?p=163972#p163972
With that, oscillators of every period are known: Conway's Game of Life is omniperiodic! This has been one of the major open problems in the study of Conway's Game of Life even since its invention over fifty years ago.
This comes just 7 days after the second-to-last period, period 19, was discovered.
@isaacg this sounds really cool but what is the context to this? Like why is it exciting to know that this automaton can do oscillations of any period? Is there a generalization argument available here?