In: Physics
Computer systems use electronic circuits which exist in only one of two states the binary number system is a method of representing numbers that counts by using combinations of only two numerals: zero (0) and one (1). The computer's only recognises two states, on or off. Binary simplifies information processing. Because there must always be at least two symbols for a processing system to be able to distinguish significance or purpose, binary is the smallest numbering system that can be used.
We only use binary because we currently do not have the technology to create "switches" that can reliably hold more than two possible states. (Quantum computers aren't exactly on sale at the moment.) The binary system was chosen only because it is quite easy to distinguish the presence of an electric current from an absense of electric current, especially when working with trillions of such connections. And using any other number base in this system ridiculous, because the system would need to constantly convert between them. That's all there is to it.