There are a handful of unscientific experiments circulating around, like this Mythbusters one: https://www.youtube.com/watch?v=0f4sUNWkq60 https://www.youtube.c

There are a handful of unscientific experiments circulating around, like this Mythbusters one: https://www.youtube.com/watch?v=0f4sUNWkq60 https://www.youtube.com/watch?v=0f4sUNWkq60 . Tl;dr: 6 feet is optimistic. But, compared to 2 feet it's probably worlds better. It's a numbers game.