The Bit

Mission 0: The Information Problem. Part of the Quantum Courier Service, a free course from the Oxford University Quantum Information Society.

A bit is the universe’s simplest switch. It has no personality, no shades of gray, and zero capacity for compromise. It is a digital binary.

• ON or OFF
• 1 or 0
• Heads or Tails
• High Voltage or Low Voltage

A single bit is practically useless; it can only tell you if it’s raining or not (which, in Oxford, is usually a safe guess anyway). But when you start chaining these switches together, magic happens. When you send a high-resolution photo across the internet, you aren't actually sending an image. You are throwing a massive, synchronized parade of billions of microscopic electrical switches down a wire. The receiving computer just watches these switches flip and reconstructs the picture.