And older telescopes can detect only strong, simple signals of the sort emitted by small molecules like carbon monoxide and hydrogen cyanide, which have two and three atoms respectively.
A generator engine, just like any other combustion engine, emits carbon monoxide, a harmful gas that can cause a splitting headache and make you pass out.
Carbon monoxide is an invisible and odourless gas produced in all fires, it takes up the place of oxygen in the blood thereby reducing the supply of oxygen to the brain.
Unlike the gas giants of the outer solar system, Pluto has no rings, but it does have a thin atmosphere made mostly of nitrogen, with small amounts of methane and carbon monoxide.
All of those cars idling inside of the tunnel for hours produce a lot of carbon monoxide that stuck around and killed at least 176 people while they were waiting.