We only know about when humans mastered fire or started using metal. But we know the exact date when the first powered flight took place. What are some really early “first ____” we know the date of for sure?
We only know about when humans mastered fire or started using metal. But we know the exact date when the first powered flight took place. What are some really early “first ____” we know the date of for sure?
I kind of wonder if time might be infinite in both directions, just because having a definitive beginning or end would seem to violate the conservation of matter and energy.