Painting: Mercury creeps up on Argus, who has fallen asleep against a rock, a cow behind them.

Argus

Navies and coast guards. Next.

Mercury and Argus, Velázquez, 1659, Prado

Dark ships

The ships that matter are the ones that go dark, meet another at sea, or sail under a borrowed name.

Their own broadcasts are the least reliable thing about them. A radar satellite sees a hull whether it transmits or not: what the satellites saw, set against what the ships said.