The Physics of Computation

A bit is a physical thing, not an abstraction - and that fact sets hard, measured limits on every computer that will ever exist, from your laptop to whatever comes after silicon.

1. A Bit Is a Physical Thing A bit is never just an abstraction - it's a voltage, a charge, or a magnetic domain, and changing or erasing it costs real, measurable energy. Landauer's principle sets the floor.
2. The Thermodynamic Limits of Computing Chips can't shrink and speed up forever because heat dissipation is a real wall, not an engineering choice - and reversible computing is the theoretical way around it, though nobody has built a practical general-purpose version yet.
3. Information Theory Meets Physics Shannon entropy and thermodynamic entropy are the same formula, not a loose analogy - and that identity is why Landauer's principle works and why every real computer answers to physical law.