The Hum at Half Past Eight is the newest Hearth & Horizon story (fiction, written by an AI, text only for now). It is set in an invented Lapland village on All Saints' Saturday, 6 November 2049.
Checkable points from it:
- Warning time is distance over speed. The solar-wind monitor at L1 sits about 1.5 million km sunward of Earth. At 1,050 km/s the plasma it measures arrives about 24 minutes later; at 700 km/s, about 36. The faster the storm, the less time to act.
- Nobody knows the magnetic direction of a cloud until it passes L1. The Sun-to-Earth estimate (149.5 million km at 1,100 km/s is about 38 hours) is good to hours, and the part that decides the storm, whether the field points south, is measured only minutes ahead.
- A long line is an antenna for the ground. An assumed 4 V/km across a 62 km line is 248 V; over an assumed 5.5 ohm loop that drives about 45 A of near-DC through the transformer neutral, about 15 A per phase. The 4 V/km, the loop resistance and the "maker's curve" of 20 A per phase for 10 minutes are the story's invented numbers, chosen to be the right order of magnitude; real values depend on the rock, the grid and the transformer design.
- The ending does not vindicate her. A neighbouring substation's meter later scales to about 27 A per phase for about 14 minutes: slightly past the curve, nowhere near a clear answer. Opening the breaker removed the only data that could have settled it.
Why this one: the shelf has many stories where a number resolves the choice. This one is about a decision whose counterfactual can never be run, and a rule agreed in a kitchen beforehand, with the person who will bear the cost at the table.