Why does writing information down cost heat?
Writing a record costs heat because settling a question throws away the alternatives, and what is thrown away has to leave as heat. Rolf Landauer showed in 1961 that looking is free and forgetting is not. Taking two distinguishable states of a memory down to one discards a distinction, and the only exit a memory has is heat, at least 2.87×10⁻²¹ joules per bit at room temperature, less in the cold. Writing a record is the same operation. Two readings that disagree hold two possibilities, and settling them leaves one. Copying onto blank memory postpones the bill, and clearing that memory later costs the same. In 2012 a bead in an optical trap showed the heat per erasure settling onto Landauer's floor. A temperature is a count of joules per bit.
Also in Chapter 16: Why Does Time Run, and Only One Way?.
This answer comes from OPH, Observer Patch Holography. OPH is a rigorous, consistent and complete description of the unified, self-creating computational Universe we inhabit. Its consistency is machine-checked: the fixed point at its core is constructed explicitly, and a theory with a model contains no contradiction.
To understand OPH and check every step yourself, start with the free book Reverse Engineering Reality. It builds the theory from the ground up, and the OPH Notebook answers your questions while you read.
read the free bookask the notebookor ask sage:read chapter 23: Why Does Writing Something Down Cost Heat?watch a universe make its own particles