Analog signals can only be “perfectly” reproduced up to a specific target frequency. Given the actual signal is composed of infinite frequencies, you needs twice infinite sampling frequency to completely reproduce it.
“The mean free path in air is 68nm, and the mean inter-atomic spacing is some tens of nms about 30, while the speed of sound in air is 300 m/s, so that the absolute maximum frequency is about 5 Ghz.”
Analog signals can only be “perfectly” reproduced up to a specific target frequency. Given the actual signal is composed of infinite frequencies, you needs twice infinite sampling frequency to completely reproduce it.
There aren’t infinite frequencies.
“The mean free path in air is 68nm, and the mean inter-atomic spacing is some tens of nms about 30, while the speed of sound in air is 300 m/s, so that the absolute maximum frequency is about 5 Ghz.”
The term “mean free path” sounds a lot like an average to me, implying an distribution which extends beyond that number.