[phoe-krk]

A telescope looking through a proper window at nighttime could be enough. Some LEDs are powerful enough to illuminate a large chunk of an otherwise dark room.

[jaywalk]

The point is that the air-gapped system would have to be compromised first.

[0xCMP]

And not in a windowless room already.

How many air gapped systems are running next to a Window?

Although I guess you can use this as evidence: if it needs to be air-gapped it also needs to be in a windowless room or some kind of sealed container.

[bentcorner]

How long before we have people shooting cosmic rays at air-gapped systems in windowless rooms and measuring bit flips?

[rgj]

Most of the time the system is compromised before being in an air gapped setup, for instance in the supply chain.