Every time a mind uses or forgets information, real energy moves. The piece follows that force from your own hand to the edge of the universe.
The title comes from Leo Szilard’s 1929 paper, “On the decrease of entropy in a thermodynamic system by the intervention of intelligent beings.” Physics already has a slot for minds. The piece follows it.
The equation
ΔS ≥ 0 is the second law: disorder always wins. As the piece goes on, it is rewritten to include information, I. Knowing lets you do work. Forgetting costs heat. At the end it becomes a ceiling.
The sound
Hiss is disorder. Tone is order. A click is always exactly one erased bit.
What happens
The box and the door
You play Maxwell’s demon (1867). You hold a door so only fast molecules pass, and one side heats while the other cools: order from knowledge alone. Your choices fill a 64-bit memory. To keep going, it has to be erased, and that is where the first clicks come from.
The bench
In 2012, a lab in Lyon measured the heat of erasing one bit, held as a glass bead in a two-well laser trap: about 3×10−21 joules, as Landauer predicted in 1961. Moving your hand changes how fast you erase, and fast erasures cost more. A 2010 Tokyo experiment made a particle climb stairs powered only by observation. Then there is your brain: 20 watts, acting at roughly 10 bits a second.
The planet
Humanity runs on about 19 terawatts. That is inside the error bar of the heat from Earth’s own radioactivity (20 ± 9 TW). Under cities the ground vibrates on a seven-day week. In 2022, a spacecraft shortened an asteroid’s orbit by 33 minutes. Your 20 watts of thought leave Earth as infrared light near 11 microns.
Early
If small red stars can host life, the likeliest time for it is ten trillion years from now. The clock you see is your own local time.
The cold side
Forgetting is cheaper in the cold, so you lower the temperature toward the 2.7 K sky. A mature civilization would wrap its stars and glow only in infrared, and the galaxy dims. Near a fast-spinning black hole, even the cold sky becomes the hot side. A real search of 100,000 galaxies found none turning more than 85% of its starlight into waste heat.
The horizon
Expanding civilizations can be modelled as bubbles in a cosmic phase transition. Here they turn the web of galaxies into designed order. A perfectly efficient signal looks exactly like heat, so that order fades into a uniform glow. The last equation is the ceiling, 1070 joules: the energy inside the cosmic horizon. Then you are asked to forget one bit, the smallest possible act of the same force.
Your click and a rearranged universe are the same physics at different sizes. You are the first version of it.
What you can do
hold to open the door (space bar works too)
move left and right at the bench to set how fast you erase
hold or drag to lower the temperature
press once at the end to forget one bit
The corner log is an instrument. It notices when you are still, when you look away, and what time it is where you are.
Sources
L. Szilard, Z. Physik 53, 840 (1929)
J. C. Maxwell, letter to P. G. Tait (1867)
R. Landauer, IBM J. Res. Dev. 5, 183 (1961)
A. Bérut et al., Nature 483, 187 (2012), Lyon
S. Toyabe et al., Nature Physics 6, 988 (2010), Tokyo